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Patient preferences for CT colonography, conventional colonoscopy, and bowel preparation
THE AMERICAN JOURNAL OF GASTROENTEROLOGY © 2003 by Am. Coll. of Gastroenterology Published by Elsevier Science Inc.
Vol. 98, No. 3, 2003 ISSN 0002-9270/03/$30.00 doi:10.1016/S0002-9270(02)06024-0
Patient Preferences for CT Colonography, Conventional Colonoscopy, and Bowel Preparation Stephen L. Ristvedt, Ph.D., Elizabeth G. McFarland, M.D., Leonard B. Weinstock, M.D., and Eric P. Thyssen, M.D. Department of Psychiatry, Mallinckrodt Institute of Radiology, and Department of Gastroenterology, Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
OBJECTIVES: The aim of this study was to determine patient pre-examination expectations and postexamination appraisals for CT colonography, conventional colonoscopy and bowel preparation. METHODS: Prospective evaluation of 120 patients at defined risk for colorectal neoplasia was performed with CT colonography followed by colonoscopy on the same day. Subjects were stratified by age and sex (67 women and 53 men) and were randomized to receive either manual air (n ⫽ 61) or CO2 (n ⫽ 59) insufflation during CT colonography. Patients’ expectations were assessed just before the two examinations, and appraisals were assessed 2 to 3 days afterward regarding pain/discomfort, embarrassment, difficulty, overall assessment, preference for future testing, and bowel preparation. RESULTS: No significant differences were found in appraisals of manual air versus CO2 insufflation techniques. For both CT colonography and colonoscopy, patients’ appraisals after the procedure were significantly more positive than prior expectations. Patients expressed more favorable appraisals of colonoscopy for pain (p ⬍ 0.001) and embarrassment (p ⬍ 0.001), with most responses being “none” to “a little” for both examinations. Overall appraisals of the tests were favorable and similar between CT and colonoscopy: patients mainly expressed “not unpleasant” to “a little unpleasant” (95%, 114/120 for both examinations). Overall, appraisal of the bowel preparation was the most negative. Preferences for future testing were more favorable toward CT: of the patients, 58% (69/120) preferred CT, 14% (17/120) preferred colonoscopy, and 28% (34/120) had no preference. CONCLUSIONS: Overall appraisals were similar and positive for both CT colonography and colonoscopy, with less favorable appraisals of the bowel preparation. Most patients stated that they would prefer CT for future evaluation. (Am J Gastroenterol 2003;98:578 –585. © 2003 by Am. Coll. of Gastroenterology)
cancer; yet rates of participation in screening are still well below optimal (1–3). Although participation in screening increased between 1987 and 1992 (4, 5), actual rates of adherence with recommended guidelines have still been far from satisfactory. Mathematical models have shown that the costs of colorectal cancer screening are well below the federal cutoff for an intervention to be cost-effective (6). However, one study found that the most important determinant of the cost-effectiveness of each screening option was adherence (7). The low use of screening is due in part to poor patient acceptance (8). Consequently, the success of any cancer screening program and the associated technology depends significantly on public acceptance and attitudes (8 –11). A rapidly evolving examination for detection of colorectal neoplasms is CT colonography (also “virtual colonoscopy”) (12–16). After the noninvasive and time-efficient acquisition of CT images, computer-simulated three-dimensional endoscopic visualization of the colonic mucosal surface is used. In addition, two-dimensional image display techniques can be simultaneously visualized to provide an extraluminal orientation of the colonic anatomy. For the patient, the noninvasive nature of this technology permits several advantages, including lack of sedation and monitoring of vital signs, along with no requirement for a recovery period. Disadvantages include the use of a conventional bowel preparation and potential discomfort during insufflation of the colon per rectum. Overall, the advantages of CT colonography could improve patient compliance with colorectal screening; however the factors affecting compliance need to be rigorously assessed. Our purpose was to prospectively perform CT colonography and conventional colonoscopy in a cohort of patients at defined risk for colorectal neoplasia, to compare differences in patient pre-expectations before, and appraisals afterward, for CT colonography and colonoscopy as well as for bowel preparation.
INTRODUCTION
MATERIALS AND METHODS
Detection and removal of early stage carcinomas or precursor lesions (adenomatous polyps) can prevent a substantial proportion of the suffering and mortality from colorectal
Subjects A total of 120 subjects were recruited for this prospective trial of CT colonography in patients at increased risk for
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colorectal neoplasia, using colonoscopy as the reference standard. Patients were recruited from July, 2000, to May, 2001, as part of the NCI PLCO (Prostate-Lung-Colon-Ovary Screening Trial (17). Recruitment criteria used to define patients at increased risk for colorectal neoplasia were the following: currently suspected polyps (n ⫽ 26), rectal bleeding (n ⫽ 16), positive hemoccult stool (n ⫽ 17), history of prior polyps (n ⫽ 9), family history of colorectal cancer (n ⫽ 39), and personal history of colorectal cancer (n ⫽ 7). An additional six patients who were being scheduled for a colonoscopy were recruited beyond our criteria (retrospectively determined) with the following: inflammatory bowel disease (n ⫽ 2), diarrhea (n ⫽ 1), constipation (n ⫽ 1), and screening (n ⫽ 2). As part of a randomized control trial comparing air versus CO2 insufflation techniques at CT colonography, patients selected were entered into either air or CO2 arms of the CT colonography examination with stratified randomization of sex and age (ⱕ60 yr, ⬎60 yr). Patients were recruited from the Barnes-Jewish Hospital GI outpatient services. The study was approved by the institutional review board, and all subjects gave informed consent. CT and Colonoscopy Examinations On the day before the CT and colonoscopy examinations, all patients underwent a standard bowel cleansing preparation. Of the patients, 109 had a 1-day Fleet Phospha-Soda preparation (Fleet Pharmaceuticals, Lynchburg, VA), and 11 had PEG electrolyte solution (GoLytely, Braintree Laboratories, Braintree, MA), along with a clear liquid diet. Each patient underwent the CT examination just before the colonoscopy examination. For the CT examination, air or CO2 was insufflated per rectum in each patient using a small rectal catheter and hand bulb by an abdominal radiologist. In general, a steady delivery of the gas was instilled by the radiologist, with the endpoint of total gas instilled being balanced by patient tolerance and image quality. Namely, the radiologist carefully watched the patient’s reactions, and the patient was asked how he or she was doing during the insufflation. If inadequate distention was seen in the preliminary images, further instillation of the air or CO2 was carefully performed, as tolerated by the patient. Each patient was initially placed in the right lateral decubitus position for the initial insufflation of air or CO2. The patient was then rolled to the supine position and the remaining air or CO2 was instilled, according to patient tolerance. After the supine acquisition, the patient was placed prone and an additional CT examination was performed. An anteroposterior CT topogram (preliminary scout view) was acquired to confirm adequate insufflation after both the supine and prone position, and further air or CO2 was instilled per rectum as needed. Because of the faster resorption times of CO2 (18 –20), CO2 was instilled more frequently between the supine and prone acquisitions. Of note, for the first 10 CO2 patients, an automated delivery of CO2 was used as part of the protocol design, using a laparoscopic insufflator device (Richard
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Wolf Medical Instruments, Vernon Hill, IL). There was difficulty maintaining steady flow of CO2 in four of these first 10 patients, with premature termination of flow when maximal intraluminal pressure exceeded the upper limit of 24-mm maximal pressure (most likely because of colonic tortuosity and retained fluid). As the method of gas delivery seemed to be an additional influence, the study design was simplified to compare manual delivery of air and CO2 in the remaining patients. Because there were no clear differences in study results between these first 10 CO2 patients with an automated insufflation and the remaining 50 CO2 patients with manual insufflation, all CO2 patients were included in the study analysis. Images of the abdomen and pelvis were obtained in supine and prone positions with a multirow detector CT scanner (Volume Zoom, Siemens Medical Systems, Iselin, NJ), using 2.5-mm detector width, 3.0-mm effective slice thickness, table increment of 15 mm, 100 effective mAs, 120 kvp, and reconstruction interval of 1 to 2 mm. Image acquisition times ranged from 10 to 18 s per position. After completion of the CT examinations, a small red rubber catheter was exchanged per rectum and the gas was allowed to decompress for 2 to 3 min. The patients then typically went to the bathroom to further evacuate any residual gas or fluid. Colonoscopy was performed directly after the CT examination. Patients underwent routine colonoscopy using a standard adult videocolonoscope (Olympus CF-AL160, Olympus of America, Lake Success, NY) by board-certified gastroenterologists at Barnes Jewish hospital. Routine medications (meperidine and midazolam) were given with nursing supervision during the examination. After the colonoscopy, the gastroenterologists rated qualitatively the patient compliance (excellent, good, fair, or poor). Materials To assess relative preferences for the two techniques, patients were queried at three successive time points during the study. Time 1 was just before CT, time 2 was just after CT but before colonoscopy, and time 3 was 2 to 3 days after both procedures. One research assistant conducted all three structured interviews, the first two face-to-face, and the third by telephone. At time 1, subjects were asked several questions about their expectations for the testing. Multiple choice questions were developed that required subjects to rate their expectations regarding the amount of Pain or Discomfort, Embarrassment, and Difficulty that they expected to experience with each of the two examinations. The response choices were None, A Little, Moderate, A Lot, or Extreme. Subjects were also asked if any of those expectations (Pain/Discomfort, Embarrassment, or Difficulty) would be significant enough to decrease their willingness to have the examination(s) performed in the future. Finally, subjects were asked to provide a global rating of their overall expectation for each examination (Not Unpleasant, A Little Unpleasant,
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Somewhat Unpleasant, Very Unpleasant, or Extremely Unpleasant). At time 2, conducted just after completion of the CT test and before the colonoscopy examination, subjects were asked to rate their experiences regarding that examination. Subjects rated their posttest appraisals of the CT test using the same scales used to rate expectations at time 1. The main purpose of the time 2 CT colonography immediate posttesting assessment was to confirm stability in the measurements with time 3, the major postappraisal assessment. At time 3, subjects were contacted by telephone by the interviewer within 2 to 3 days after the examinations to assess their posttesting comparative appraisals of both CT and colonoscopy. Once again, subjects rated the amount of Pain or Discomfort, Embarrassment, and Difficulty that they experienced with CT, whether any of those experiences would be significant enough to decrease their willingness to have the examination performed in the future, and they provided a global rating of their overall appraisal of the examination. In addition, subjects were asked, “In the future, which test would you prefer to have done?” (CT, Colonoscopy, No Preference). Those subjects who expressed a preference for one examination over the other were then asked, “How much did you prefer the ________ to the __________?” (A Slight Preference, A Moderate Preference, A Strong Preference, or A Very Strong Preference). Subjects were also asked questions about the bowel preparation, because it is one common feature of both CT and colonoscopy examinations and also one aspect of testing toward which subjects typically have their most negative reaction. The same questions were asked regarding the bowel preparation at both time 1 and time 3. Subjects were asked about their overall reaction to the bowel preparation (Not Unpleasant, A Little Unpleasant, Somewhat Unpleasant, Very Unpleasant, or Extremely Unpleasant). Subjects were also asked how much they might have disliked different aspects of the bowel preparation (i.e., the liquid diet, drinking the fluid, making frequent trips to the bathroom) by rating their dislike of each of these features on multiple choice scales (Not At All, A Little, Moderately, A Lot, or Extremely). Finally, at time 3, subjects were asked to appraise miscellaneous features of the two examinations, including Pain, Sedation, and Lost Time. Subjects were asked how much they might have disliked Pain or Lost Time, and how much either of those features might decrease their willingness to have testing in the future. Regarding sedation, subjects were asked whether (and how much) sedation might either increase or decrease their willingness to have testing in the future. Statistical Analysis Comparisons of reactions to air versus CO2 techniques at CT colonography were evaluated for differences. When no significant differences were found between CT techniques,
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CT results collectively (air and CO2) were then compared to colonoscopy results in the following: expectations for CT versus colonoscopy and reactions before versus after to CT and colonoscopy, respectively. Comparisons of the overall appraisals of the bowel preparation, CT, and colonoscopy were also performed. All comparisons were tested for statistical significance using the Wilcoxon signed ranks test for two reasons. First, all comparisons were paired within subjects, either comparisons between the two examination types at the same point in time or comparisons of the same examination at two points in time. Second, most of the distributions were strongly skewed in the positive direction, thus violating a principal parametric assumption. The Wilcoxon signed ranks test was chosen because of its sensitivity to the magnitude of differences between two paired variables, to glean the most information possible from these data (21). All tests were two-tailed, and statistical significance was defined as p ⬍ 0.05.
RESULTS Randomization and Patient History Of the subjects, 67 (55.8%) were female (33 air and 34 CO2) and 53 (44.2%) were male (26 air and 27 CO2). The mean (⫾ SD) age was 58 ⫾ 8.2 yr (range 38 –75 yr). Also, 94 (78.3%) were Caucasian, 24 (20.0%) were African American, and two (1.7%) were Asian. Results of patients’ GI history, collected by the study coordinator on the day of the CT examination, demonstrated the following incidence of: 27/120 (22.5%) prior GI surgery, 14/120 (11.7%) use of laxatives, four of 120 (3.3%) irritable bowel syndrome, one of 120 (0.8%) pelvic floor relaxation, six of 120 (5.0%) diverticular disease. Pre-examination Expectations Versus Postexamination Appraisals Subjects’ ratings of both examinations, taken both before and after they were done, are shown in Table 1. Subjects’ comparative expectations for the two examinations were assessed at time 1. As can be seen, subjects expected to experience more pain with colonoscopy than with CT, and this difference was statistically significant (z ⫽ ⫺2.371, p ⬍ 0.05). However, the differences occurred primarily between ratings of “A Little” and “Moderate,” so subjects did not expect too much pain with either test. Subjects also expected more embarrassment with colonoscopy (z ⫽ ⫺2.489, p ⬍ 0.05), although again the shifts occurred at the lower end of the scale. Subjects expected more difficulty with colonoscopy compared to CT, although this difference was not significant (z ⫽ ⫺1.644, p ⫽ 0.10). Overall, subjects expected the colonoscopy to be more unpleasant than CT (z ⫽ ⫺1.998, p ⬍ 0.05). At time 3, performed by telephone interview within 2 to 3 days after the examinations, subjects were asked to appraise the two examinations, which made it possible to compare their pretest expectations with their posttest ap-
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Patient Preferences for CT Colonography
Table 1. Comparisons Between Spiral CT and Colonoscopy Spiral CT
Colonoscopy
Pre Post Pre Post (n ⫽ 120) (n ⫽ 120) (n ⫽ 120) (n ⫽ 120) Pain/discomfort None A little Moderate A lot Extreme Embarrassment None A little Moderate A lot Extreme Difficulty None A little Moderate A lot Extreme Overall (“Unpleasant”) Not A little Somewhat Very Extremely
0.28 0.53 0.15 0.04 0.00
0.39 0.48 0.11 0.02 0.00
0.26 0.41 0.27 0.06 0.01
0.84 0.12 0.02 0.02 0.00
0.58 0.29 0.08 0.02 0.02
0.69 0.26 0.04 0.01 0.00
0.50 0.33 0.11 0.04 0.02
0.93 0.07 0.00 0.00 0.00
0.66 0.27 0.06 0.01 0.01
0.82 0.17 0.02 0.00 0.00
0.58 0.33 0.08 0.02 0.00
0.97 0.03 0.00 0.00 0.00
0.21 0.59 0.18 0.02 0.01
0.57 0.38 0.05 0.00 0.00
0.21 0.45 0.32 0.02 0.00
0.68 0.28 0.04 0.00 0.01
praisals. Compared to their expectations, subjects generally found CT at time 3 to be somewhat less painful (z ⫽ ⫺1.890, p ⫽ 0.06), as well as significantly less embarrassing (z ⫽ ⫺3.121, p ⬍ 0.005), less difficult (z ⫽ ⫺3.169, p ⬍ 0.005), and less unpleasant overall (z ⫽ ⫺5.854, p ⬍ 0.001). Parenthetically, subjects’ appraisals of CT at time 2, measured immediately after the CT and before colonoscopy, were very similar to appraisals measured at time 3 by telephone interview 2 to 3 days after both examinations. The one difference that emerged was that subjects reported lower levels of pain/discomfort at time 3 compared to time 2 (z ⫽ ⫺3.703, p ⬍ 0.001). The main purpose of time 2 testing was to assess stability of the assessments immediately after CT compared to 2 to 3 days after CT. Compared to expectations regarding colonoscopy, subjects found the actual examination at time 3 to be less painful (z ⫽ ⫺7.420, p ⬍ 0.001), less embarrassing (z ⫽ ⫺6.667, p ⬍ 0.001), less difficult (z ⫽ ⫺6.195, p ⬍ 0.001), and less unpleasant overall (z ⫽ ⫺7.112, p ⬍ 0.001). Postexamination appraisals obtained at time 3 allowed comparisons between the two tests regarding actual experiences. Time 3 was the major postappraisal assessment for both CT and colonoscopy, as it was believed to be the best assessment of colonoscopy after full recovery from medications. As can be seen, subjects tended to have more favorable reactions to colonoscopy in terms of pain (z ⫽ ⫺6.024, p ⬍ 0.001), embarrassment (z ⫽ ⫺4.957, p ⬍ 0.001), and difficulty (z ⫽ ⫺3.911, p ⬍ 0.001). It is important to note, however, that most of the ratings of both
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tests were either in the “None” or “A Little” categories. Also, subjects did not view the two tests to be significantly different in the overall ratings (z ⫽ ⫺1.434, ns). Finally, analyses were conducted to investigate whether there were differences in ratings of the two examinations according to the sex of the patient, and three differences were found regarding pre-examination expectations. Women expected greater pain and discomfort with the CT colonography compared to men (z ⫽ ⫺1.994, p ⫽ 0.046). Women also gave more negative overall expectations than men for both CT (z ⫽ ⫺2.375, p ⫽ 0.018) and colonoscopy (z ⫽ ⫺2.294, p ⫽ 0.022). Interestingly, there were no gender differences found for any of the postexamination appraisal ratings. Overall Preferences (Future Tests) With regard to overall preferences for the two screening tests, 69 (57.5%) of the subjects preferred CT, 17 (14.2%) preferred colonoscopy, and 34 (28.3%) stated that they had no preference. For those subjects who reported a preference, the magnitude of that preference was measured. Of the 69 subjects who preferred the CT examination, the preference was Slight for 11 (15.9%), Moderate for 13 (18.8%), Strong for 27 (39.1%), and Very Strong for 18 (26.1%). Of the 17 subjects who preferred the colonoscopy, the preference was Slight for four (23.5%), Moderate for five (29.4%), Strong for four (23.5%), and Very Strong for four (23.5%). The difference in magnitude of the preferences was not significant. Because initial analyses revealed a clear disparity between the posttest comparative appraisals of the two tests and the global preference ratings, another question was added to the time 3 interview for the last 47 subjects. After stating their global preference for testing, these subjects were asked the open-ended question: “Why do you feel this way?” Of these 47 subjects, 25 subjects preferred CT, seven preferred colonoscopy, and 15 stated that they had no clear preference. The general feeling among the 25 subjects who preferred the CT examination was that it was quicker, easier, less invasive, and did not require sedation. For the seven subjects who preferred colonoscopy, they either liked the fact that there was only one test or that they could “sleep through” the procedure. Bowel Preparation Subjects indicated their reactions to the bowel preparation at both time 1 and time 3, as shown in Table 2. Two trends are worth noting about these data. First, subjects were able to discriminate among the listed features of the preparation in terms of unpleasantness. Subjects reported that drinking the fluid was the most unpleasant aspect of the preparation. Of note, based on the participating gastroenterologists’ recommendations, most of the subjects (n ⫽ 109) received Phospha-Soda, whereas the remaining subjects (n ⫽ 11) received GoLytely. Subjects reported that drinking the fluid was more unpleasant than having to take frequent trips to the
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Table 2. Bowel Preparation Appraisal Time 1 (n ⫽ 120)
Time 3 (n ⫽ 120)
Liquid diet (“How much did you dislike. . .) Not at all 0.18 0.44 A little 0.44 0.25 Moderately 0.25 0.20 A lot 0.08 0.08 Extremely 0.05 0.03 Drinking the fluid (“How much did you dislike. . .) Not at all 0.11 0.19 A little 0.31 0.25 Moderately 0.20 0.22 A lot 0.23 0.16 Extremely 0.15 0.18 Frequent trips to the bathroom (“How much did you dislike. . .) Not at all 0.09 0.22 A little 0.31 0.34 Moderately 0.30 0.20 A lot 0.23 0.16 Extremely 0.07 0.08 “How much would the bowel preparation decrease your willingness to have either test?” Not at all 0.55 0.81 Slightly 0.24 0.10 Moderately 0.13 0.08 A lot 0.05 0.01 Would refuse 0.01 0.00
bathroom (time 1: z ⫽ ⫺1.059, p ⫽ 0.290; time 3: z ⫽ ⫺2.764, p ⬍ 0.01), which was in turn more unpleasant than having to be on a liquid diet (time 1: z ⫽ ⫺4.490, p ⬍ 0.001; time 3: z ⫽ ⫺3.755, p ⬍ 0.001). The second trend worth noting is that subjects tended to give less negative ratings of these features at time 3 compared to time 1. This trend was statistically significant with regard to the liquid diet (z ⫽ ⫺3.920, p ⬍ 0.001) and having to take frequent trips to the bathroom (z ⫽ ⫺3.240, p ⬍ 0.001). Most importantly, subjects’ judgments of the negative impact that the bowel preparation would have on their willingness to have either type of examination in the future also lessened between time 1 and time 3 (z ⫽ ⫺4.528, p ⬍ 0.001). At time 3, subjects gave overall assessments of each of the two screening examinations and the bowel preparation. As can be seen in Table 3, subjects clearly responded much more negatively to the bowel preparation process than to either of the two examinations. They found the bowel preparation to be significantly more unpleasant than both the CT (z ⫽ ⫺8.272, p ⬍ 0.001) and the colonoscopy (z ⫽ ⫺8.324, Table 3. Overall Appraisals (Time 3) of Bowel Preparation, CT, and Colonoscopy Preparation (n ⫽ 120) Not unpleasant A little unpleasant Somewhat unpleasant Very unpleasant Extremely unpleasant
0.12 0.27 0.38 0.17 0.07
CT Colonoscopy (n ⫽ 120) (n ⫽ 120) 0.57 0.38 0.05 0.00 0.00
0.68 0.28 0.04 0.00 0.01
p ⬍ 0.001). Lastly, subjects were asked whether there was anything about either of the two examination techniques that would decrease their willingness to have it done in the future. Regarding spiral CT, one subject indicated that “Discomfort” would decrease their willingness “slightly,” a second subject indicated that having “Radiation” would decrease their willingness “moderately,” and a third subject indicated that “Wearing the gown” would decrease their willingness “slightly.” Regarding colonoscopy, one subject indicated that having the i.v. would decrease their willingness “a lot.” On the other hand, when subjects were asked whether the bowel preparation would decrease their willingness to have either of the two examinations, 23 of the 120 subjects said “yes” (12 patients “slightly,” 10 “moderately,” and one “a lot”).
DISCUSSION A key challenge to increasing rates of participation in colorectal cancer screening will be to minimize logistic and psychological barriers. Clearer guidelines for screening, along with broader coverage by health insurers, have lowered some of those barriers. However, significant psychological barriers still remain. The development and refinement of screening technologies must be done with these issues in mind, so that progress can be made in the direction of greater public acceptance and, therefore, greater participation. Spiral CT colonography has the potential to lower some of these psychological barriers by providing a procedure that is less invasive and quicker compared to colonoscopy and does not require sedation. In this prospective study of CT colonography (air vs CO2 insufflation techniques) compared to conventional colonoscopy, we determined the following key findings. Pre-examination expectations were more negative for both CT and colonoscopy compared to postexamination appraisals for each examination; specifically, more negative pre-examination expectations were reported for colonoscopy than CT. Postexamination appraisals were similar comparing manual insufflation of air to manual insufflation of CO2 at CT colonography. Postexamination appraisals of CT (air and CO2) were more negative than colonoscopy in pain and discomfort; however, the majority of the responses were of minimal ratings. Comparing the postexamination appraisals of overall unpleasantness, the bowel preparation had significantly higher scores than either the CT or the colonoscopy examinations. Preferences for future testing demonstrated that patients would prefer CT colonography to conventional colonoscopy. To date, very few studies have looked at patients’ attitudes toward spiral CT colonography, with mixed results. Angtuaco et al. conducted a survey study of community members and physicians who were asked to state their preferences for spiral CT compared to colonoscopy (22). In general, potential patients preferred the CT to the colonoscopy, whereas physicians preferred colonoscopy. However,
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this study was based only on subjects’ preferences when presented with the hypothetical possibility of screening. Also, only about 20% of the subjects in this study were aged ⱖ 50 yr, the group for whom screening recommendations are most pertinent. Several preliminary investigations have evaluated assessments of patients who have undergone both CT colonography and colonoscopy. Forbes and Mendelson (23) studied 70 patients and determined that subjects judged the two examinations to be essentially comparable in terms of pain, embarrassment, tolerability, and overall preference. Pineau et al. (24) studied 55 patients and reported preprocedural expectations to be more positive toward CT than conventional colonoscopy. After both procedures, there were no differences in patient perceptions of the two tests, but patients preferred CT colonography for future testing. Farrell et al. (25) reported a study of 100 patients and found similar discomfort and pain scores between CT and colonoscopy at two time points. Akerkar et al. (26) conducted the largest study to date in a cohort of 295 veterans (287 men and eight women, average age 62.4 yr) from the Department of Veterans Affairs. All patients underwent CT colonography approximately 2 to 3 h before undergoing conventional colonoscopy. CT colonography was performed without medications or bowel relaxants, using manual insufflation of room air (30 – 40 bulb compressions). Conventional colonoscopy was performed with routine conscious sedation using i.v. pain and sedative medications. Data were obtained immediately after each examination and 24 h later. Using a seven-point Likert scale, patients reported more pain, more discomfort, and less respect with CT compared to colonoscopy at both time points. Using the time-tradeoff technique, patients stated that they preferred colonoscopy to CT and would be more willing to wait longer to undergo colonoscopy than undergo a CT colonography examination. The preference for colonoscopy with future testing in the Akerkar et al. study markedly contrasts with our study results regarding preference for CT colonoscopy. Differences in our study included a more balanced cohort of men and women, postexamination appraisal data collection at 1–3 days after each examination (rather than during the recovery period from conscious sedation), and use of comparative ratings rather than time-tradeoff techniques for preference in future testing. In our investigation, pre-examination expectations for conventional colonoscopy were worse than for CT colonography in terms of pain, embarrassment, and overall unpleasantness. These expectations may have been due in part to the more invasive nature of endoscopy and a lack of understanding of the effectiveness of medications for pain and sedation. On the other hand, postexamination appraisals of colonoscopy (with analgesic, sedative, and GI relaxant medications) were better than for CT colonography (with no medications), in terms of pain, embarrassment, and difficulty. These results certainly demonstrate that colonoscopy is well tolerated with appropriate medication. However, CT colonography was also performed with acceptable patient
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tolerance measured postexamination with no medications. For both colonoscopy and CT, postexamination appraisals improved compared to pre-examination expectations. There were no ratings that were more negative at the subsequent time point. In addition, less negative ratings of the pain and discomfort at CT colonography were found at time 3 (2 to 3 days after both examinations) than at time 2 (directly after CT and before colonoscopy). This pattern indicates a trend toward tempering of adverse reactions to the CT examination over the short time course of only 2 to 3 days, with the perspective of having undergone both CT and colonoscopy. This is an important trend to note for future evaluations, to arrive at the best estimate of assessments that would be more likely to influence subsequent behaviors. That is, postexamination appraisals might be more predictive of future behaviors if they are obtained at 2 to 3 days after the procedure, after patients have fully returned to normal functioning. One of the most important findings of this study was the markedly negative appraisal of the bowel preparation. The bowel preparation, currently common to both CT colonography and colonoscopy, was clearly rated as the most unpleasant of all aspects of the testing procedure. This finding seems especially important, given the magnitude of the differences in ratings given when subjects compared the bowel preparation procedure to the two screening examinations per se. Of the individual components of the bowel preparation, drinking the fluid was the most unpleasant, followed by frequent trips to the bathroom and, finally, the liquid diet. Again noted, these ratings were less negative a few days after all procedures, compared to appraisals on the morning after the bowel preparation. These findings regarding the bowel preparation will be essential to incorporate into future technical developments of dietary recommendations and cathartic regimens before GI screening examinations. Preliminary work in stool tagging and subtraction in CT colonography has shown promising results (27, 28). Such efforts could prove to be extremely valuable in improving both image quality and patient acceptance. Several influences of our CT methods are important to recognize. For both air and CO2 insufflation techniques at CT colonography, the total gas instilled by the radiologist was influenced both by how the patient was tolerating the procedure and by judging whether adequate colonic distention was seen in the images. Our use of manual methods of insufflation is another important factor. Although the automated insufflation technique with CO2 was initially used, there was variable success in patients with tortuous colons or retained fluid. Thus, to eliminate the additional influence of method of insufflation, the comparison between air and CO2 was changed to use manual insufflation techniques for both. More CO2 was generally given than air because of the faster absorption rate of CO2. Although we found no differences between manual methods of air and CO2 insufflation techniques, further evaluation with automated insufflation techniques may be warranted. Finally, no GI relaxants
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were given to patients at CT colonography in this investigation. This was based on the controversial benefit previously reported with the use of glucagon (29). In our prior experiences, we have used both Glucagon and Robinol; however, we experienced only a marginal improvement in colonic insufflation in these patients, sometimes at the expense of patient dissatisfaction to an i.v. injection or overinsufflation of the small bowel. Buscopan has been used in Europe with reported success; however, approval of its use in the United States has not been given by the Food and Drug Administration. More effective use of GI relaxants in future investigations of CT colonography could certainly improve patient tolerance and bowel insufflation. Finally, our study cohort and methods of patient preference assessments are important influences to consider. In the subject sample studied here, the distributions of age, sex, and ethnicity are comparable to those that would likely be seen in a population presenting for colon screening. It is thus unlikely that the results are influenced by any systematic artifacts of nonrepresentative demographics. One important influence for which we did not control in this study cohort was the potential bias imparted in some subjects who may have had prior colorectal screening examinations such as flexible sigmoidoscopy (30), barium enema, or colonoscopy. In these patients, previous good or bad experiences may have affected both their expectations before and their appraisals afterward. Other potential influences in this cohort were the added personal attention (with regard to any pain, discomfort, or embarrassment that they may have experienced) and monetary compensation provided as part of a carefully controlled research protocol. Because of these factors, subjects may have responded more favorably overall. With regard to the questionnaires that were used, it is important to note that the majority of ratings were on the lower end of the scales (e.g., “None” to “A little”). This suggests that subjects may have minimized any negative reactions to the two examinations, thus making finer discriminations difficult. However, the fact that the ratings of the bowel preparation showed more even distributions across the scales, extending much more into the negative end of the scale, indicates that the ratings given to the examinations per se were probably placed appropriately in the larger context of the entire experience. Finally, the paradoxical trend in preference for CT colonography in future testing (despite more negative CT assessments) may indicate that some patients were basing their future preferences on influences beyond those that were measured. The last 47 subjects indicated that their future preferences for CT were based on the quick, easy, and noninvasive nature of the examination. We can only speculate about other possible influences on future preferences for CT. Those might include the perception that CT is a more “high tech” procedure and the “wave of the future,” thus making it more desirable for future testing. In summary, this prospective study of CT colonography and colonoscopy demonstrated less favorable pre-examina-
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tion expectations but more favorable postexamination appraisals for colonoscopy. However, overall CT colonography received excellent postexamination appraisals and was preferred for future evaluations. The bowel preparation received significantly less favorable appraisals than either CT colonography or conventional colonoscopy. Efforts to improve methods of catharsis and dietary restrictions will be critical in directing future investigations. The resulting assessments of patient acceptance will then need to be included. To those ends, effective efforts aimed at decreasing current barriers to public acceptance could have a significant positive impact on the early detection of colorectal cancer.
ACKNOWLEDGMENTS This research was supported by National Institutes of Health grant N01 CN25516 to Elizabeth G. McFarland, M.D., and as a subcontract of the National Cancer Institute ProstateLung-Colon-Ovary Screening Trial (N01-CN-25516). We appreciate the support by Gerald Andriole, M.D., who is the Principal Investigator of the PLCO at Washington University School of Medicine. We acknowledge the help provided by the CT technologists at Barnes Jewish hospital of Mallinckrodt Institute of Radiology. We also greatly appreciate the thorough efforts of our dedicated study coordinator, Robin Haverman. Reprint requests and correspondence: Stephen L. Ristvedt, Ph.D., Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110-1093. Received May 30, 2002; accepted Aug. 26, 2002.
REFERENCES 1. Byers T, Levin B, Rothenberger D, et al. American Cancer Society guidelines for screening and surveillance for early detection of colorectal polyps and cancer. Update 1997. American Cancer Society Detection and Treatment Advisory Group on Colorectal Cancer. CA Cancer J Clin 1997;47:154 –60. 2. Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening. Clinical guidelines and rationale. Gastroenterology 1997;112:594 –642. 3. Weitzman ER, Zapka J, Estabrook B, et al. Risk and reluctance. Understanding impediments to colorectal cancer screening. Prev Med 2001;32:502–13. 4. Brown ML, Potosky AL, Thompson GB, et al. The knowledge and use of screening tests for colorectal and prostate cancer. Data From the 1987 National Health Interview Survey. Prev Med 1990;19:562–74. 5. Anderson LM, May DS. Has the use of cervical, breast, and colorectal cancer screening increased in the United States? Am J Public Health 1995;85:840 –2. 6. Wagner JL, Tunis S, Brown M. The cost-effectiveness of colorectal cancer screening in average-risk adults. In: Young G, Rozen P, Levin B, eds. Prevention and early detection of colorectal cancer. London: WB Saunders, 1996:321–56. 7. Lieberman DA. Cost-effectiveness model for colon cancer screening. Gastroenterology 1995;109:1781–90.
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8. Vernon SW. Participation in colorectal cancer screening: A review. J Natl Cancer Inst 1997;89:1406 –22. 9. DiPalma AM, Barnes SE, DiPalma JA. Patient participation in colon cancer screening programs. South Med J 1998;91: 342–4. 10. Leard LE, Savides TJ, Ganiats TG. Patient preferences for colorectal cancer screening. J Fam Pract 1997;45:211–8. 11. Pignone M, Bucholtz D, Harris R. Patient preferences for colon cancer screening. J Gen Intern Med 1999;14:432–7. 12. Ferrucci JT. Colon cancer screening with virtual colonoscopy: Promise, polyps, politics. Am J Roentgenol 2001;177:975–88. 13. Johnson CD, Dachman AH. CT colonography: The next colon screening examination? Radiology 2000;216:331–41. 14. McFarland EG, Brink JA. Helical CT colonography (virtual colonoscopy): The challenge that exists between advancing technology and generalizability. Am J Roentgenol 1999;173: 549 –59. 15. Fletcher JG, Luboldt W. CT colonography and MR colonography: Current status, research directions and comparison. Eur Radiol 2000;10:786 –801. 16. Rex DK. CT and MR colonography (virtual colonoscopy). J Clin Gastroenterol 1998;27:199 –203. 17. Gohagan JK, Prorock PC, Hayes RB, et al. The prostate, colon, lung, colorectal and ovarian (PLCO) cancer screening trial of the National Cancer Institute. Control Clin Trials 2000;21:251S–272S. 18. Brandt LJ, Boley SJ, Sammartano R. Carbon dioxide and room air insufflation of the colon: Effects on colon blood flow and intraluminal pressure in the dog. Gastrointest Endosc 1986; 32:324 –9. 19. Stevenson GW, Wilson JA, Wilkinson J, et al. Pain following colonoscopy: Elimination with carbon dioxide. Gastrointest Endosc 1992;38:564 –7. 20. Hussein AMJ, Bartram CI, Williams BC. Carbon dioxide
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insufflation for more comfortable colonoscopy. Gastrointest Endosc 1984;30:68 –70. Pett MA. Nonparametric statistics for health care research: Statistics for small samples and unusual distributions. Thousand Oaks, CA: Sage Publications, 1997. Angtuaco TL, Banaad-Omiotek GD, Howden CW. Differing attitudes toward virtual and conventional colonoscopy for colorectal cancer screening: Surveys among primary care physicians and potential patients. Am J Gastroenterol 2001;96: 887–93. Forbes GM, Mendelson RM. Patient acceptance of virtual colonoscopy. Endoscopy 2000;32:274 –5. Pineau BC, Sevick MA, Mikulanined C, et al. Evaluation of patient preference: Virtual colonoscopy vs. endoscopic. Gastroenterology 1999;116:486. Farrell RJ, Morrin MM, Silas A, et al. Virtual colonoscopy in patients undergoing elective colonoscopy: Diagnostic accuracy and patient tolerance. Gastroenterology 2000;118:258. Akerkar GA, Yee J, Hung R, et al. Patient experience and preferences toward colon cancer screening: A comparison of virtual colonoscopy and conventional colonoscopy. Gastrointest Endosc 2001;54:310 –5. Zalis ME, Hahn PF. Digital subtraction bowel cleansing in CT colonography. Am J Roentgenol 2001;176:646 –8. Callstrom MR, Johnson CD, Fletcher JG, et al. CT colonography without cathartic preparation: Feasibility study. Radiology 2001;219:693–8. Yee J, Hung RK, Akerkar GA, et al. The usefulness of glucagon hydrochloride for colonic distention in CT colonography. Am J Roentgenol 1999;173:169 –72. Schoen RE, Weissfeld JL, Bowen NJ, et al. Patient satisfaction with screening flexible sigmoidoscopy. Arch Intern Med 2000; 160:1790 –6.
Vol. 98, No. 3, 2003 ISSN 0002-9270/03/$30.00 doi:10.1016/S0002-9270(02)06024-0
Patient Preferences for CT Colonography, Conventional Colonoscopy, and Bowel Preparation Stephen L. Ristvedt, Ph.D., Elizabeth G. McFarland, M.D., Leonard B. Weinstock, M.D., and Eric P. Thyssen, M.D. Department of Psychiatry, Mallinckrodt Institute of Radiology, and Department of Gastroenterology, Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
OBJECTIVES: The aim of this study was to determine patient pre-examination expectations and postexamination appraisals for CT colonography, conventional colonoscopy and bowel preparation. METHODS: Prospective evaluation of 120 patients at defined risk for colorectal neoplasia was performed with CT colonography followed by colonoscopy on the same day. Subjects were stratified by age and sex (67 women and 53 men) and were randomized to receive either manual air (n ⫽ 61) or CO2 (n ⫽ 59) insufflation during CT colonography. Patients’ expectations were assessed just before the two examinations, and appraisals were assessed 2 to 3 days afterward regarding pain/discomfort, embarrassment, difficulty, overall assessment, preference for future testing, and bowel preparation. RESULTS: No significant differences were found in appraisals of manual air versus CO2 insufflation techniques. For both CT colonography and colonoscopy, patients’ appraisals after the procedure were significantly more positive than prior expectations. Patients expressed more favorable appraisals of colonoscopy for pain (p ⬍ 0.001) and embarrassment (p ⬍ 0.001), with most responses being “none” to “a little” for both examinations. Overall appraisals of the tests were favorable and similar between CT and colonoscopy: patients mainly expressed “not unpleasant” to “a little unpleasant” (95%, 114/120 for both examinations). Overall, appraisal of the bowel preparation was the most negative. Preferences for future testing were more favorable toward CT: of the patients, 58% (69/120) preferred CT, 14% (17/120) preferred colonoscopy, and 28% (34/120) had no preference. CONCLUSIONS: Overall appraisals were similar and positive for both CT colonography and colonoscopy, with less favorable appraisals of the bowel preparation. Most patients stated that they would prefer CT for future evaluation. (Am J Gastroenterol 2003;98:578 –585. © 2003 by Am. Coll. of Gastroenterology)
cancer; yet rates of participation in screening are still well below optimal (1–3). Although participation in screening increased between 1987 and 1992 (4, 5), actual rates of adherence with recommended guidelines have still been far from satisfactory. Mathematical models have shown that the costs of colorectal cancer screening are well below the federal cutoff for an intervention to be cost-effective (6). However, one study found that the most important determinant of the cost-effectiveness of each screening option was adherence (7). The low use of screening is due in part to poor patient acceptance (8). Consequently, the success of any cancer screening program and the associated technology depends significantly on public acceptance and attitudes (8 –11). A rapidly evolving examination for detection of colorectal neoplasms is CT colonography (also “virtual colonoscopy”) (12–16). After the noninvasive and time-efficient acquisition of CT images, computer-simulated three-dimensional endoscopic visualization of the colonic mucosal surface is used. In addition, two-dimensional image display techniques can be simultaneously visualized to provide an extraluminal orientation of the colonic anatomy. For the patient, the noninvasive nature of this technology permits several advantages, including lack of sedation and monitoring of vital signs, along with no requirement for a recovery period. Disadvantages include the use of a conventional bowel preparation and potential discomfort during insufflation of the colon per rectum. Overall, the advantages of CT colonography could improve patient compliance with colorectal screening; however the factors affecting compliance need to be rigorously assessed. Our purpose was to prospectively perform CT colonography and conventional colonoscopy in a cohort of patients at defined risk for colorectal neoplasia, to compare differences in patient pre-expectations before, and appraisals afterward, for CT colonography and colonoscopy as well as for bowel preparation.
INTRODUCTION
MATERIALS AND METHODS
Detection and removal of early stage carcinomas or precursor lesions (adenomatous polyps) can prevent a substantial proportion of the suffering and mortality from colorectal
Subjects A total of 120 subjects were recruited for this prospective trial of CT colonography in patients at increased risk for
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colorectal neoplasia, using colonoscopy as the reference standard. Patients were recruited from July, 2000, to May, 2001, as part of the NCI PLCO (Prostate-Lung-Colon-Ovary Screening Trial (17). Recruitment criteria used to define patients at increased risk for colorectal neoplasia were the following: currently suspected polyps (n ⫽ 26), rectal bleeding (n ⫽ 16), positive hemoccult stool (n ⫽ 17), history of prior polyps (n ⫽ 9), family history of colorectal cancer (n ⫽ 39), and personal history of colorectal cancer (n ⫽ 7). An additional six patients who were being scheduled for a colonoscopy were recruited beyond our criteria (retrospectively determined) with the following: inflammatory bowel disease (n ⫽ 2), diarrhea (n ⫽ 1), constipation (n ⫽ 1), and screening (n ⫽ 2). As part of a randomized control trial comparing air versus CO2 insufflation techniques at CT colonography, patients selected were entered into either air or CO2 arms of the CT colonography examination with stratified randomization of sex and age (ⱕ60 yr, ⬎60 yr). Patients were recruited from the Barnes-Jewish Hospital GI outpatient services. The study was approved by the institutional review board, and all subjects gave informed consent. CT and Colonoscopy Examinations On the day before the CT and colonoscopy examinations, all patients underwent a standard bowel cleansing preparation. Of the patients, 109 had a 1-day Fleet Phospha-Soda preparation (Fleet Pharmaceuticals, Lynchburg, VA), and 11 had PEG electrolyte solution (GoLytely, Braintree Laboratories, Braintree, MA), along with a clear liquid diet. Each patient underwent the CT examination just before the colonoscopy examination. For the CT examination, air or CO2 was insufflated per rectum in each patient using a small rectal catheter and hand bulb by an abdominal radiologist. In general, a steady delivery of the gas was instilled by the radiologist, with the endpoint of total gas instilled being balanced by patient tolerance and image quality. Namely, the radiologist carefully watched the patient’s reactions, and the patient was asked how he or she was doing during the insufflation. If inadequate distention was seen in the preliminary images, further instillation of the air or CO2 was carefully performed, as tolerated by the patient. Each patient was initially placed in the right lateral decubitus position for the initial insufflation of air or CO2. The patient was then rolled to the supine position and the remaining air or CO2 was instilled, according to patient tolerance. After the supine acquisition, the patient was placed prone and an additional CT examination was performed. An anteroposterior CT topogram (preliminary scout view) was acquired to confirm adequate insufflation after both the supine and prone position, and further air or CO2 was instilled per rectum as needed. Because of the faster resorption times of CO2 (18 –20), CO2 was instilled more frequently between the supine and prone acquisitions. Of note, for the first 10 CO2 patients, an automated delivery of CO2 was used as part of the protocol design, using a laparoscopic insufflator device (Richard
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Wolf Medical Instruments, Vernon Hill, IL). There was difficulty maintaining steady flow of CO2 in four of these first 10 patients, with premature termination of flow when maximal intraluminal pressure exceeded the upper limit of 24-mm maximal pressure (most likely because of colonic tortuosity and retained fluid). As the method of gas delivery seemed to be an additional influence, the study design was simplified to compare manual delivery of air and CO2 in the remaining patients. Because there were no clear differences in study results between these first 10 CO2 patients with an automated insufflation and the remaining 50 CO2 patients with manual insufflation, all CO2 patients were included in the study analysis. Images of the abdomen and pelvis were obtained in supine and prone positions with a multirow detector CT scanner (Volume Zoom, Siemens Medical Systems, Iselin, NJ), using 2.5-mm detector width, 3.0-mm effective slice thickness, table increment of 15 mm, 100 effective mAs, 120 kvp, and reconstruction interval of 1 to 2 mm. Image acquisition times ranged from 10 to 18 s per position. After completion of the CT examinations, a small red rubber catheter was exchanged per rectum and the gas was allowed to decompress for 2 to 3 min. The patients then typically went to the bathroom to further evacuate any residual gas or fluid. Colonoscopy was performed directly after the CT examination. Patients underwent routine colonoscopy using a standard adult videocolonoscope (Olympus CF-AL160, Olympus of America, Lake Success, NY) by board-certified gastroenterologists at Barnes Jewish hospital. Routine medications (meperidine and midazolam) were given with nursing supervision during the examination. After the colonoscopy, the gastroenterologists rated qualitatively the patient compliance (excellent, good, fair, or poor). Materials To assess relative preferences for the two techniques, patients were queried at three successive time points during the study. Time 1 was just before CT, time 2 was just after CT but before colonoscopy, and time 3 was 2 to 3 days after both procedures. One research assistant conducted all three structured interviews, the first two face-to-face, and the third by telephone. At time 1, subjects were asked several questions about their expectations for the testing. Multiple choice questions were developed that required subjects to rate their expectations regarding the amount of Pain or Discomfort, Embarrassment, and Difficulty that they expected to experience with each of the two examinations. The response choices were None, A Little, Moderate, A Lot, or Extreme. Subjects were also asked if any of those expectations (Pain/Discomfort, Embarrassment, or Difficulty) would be significant enough to decrease their willingness to have the examination(s) performed in the future. Finally, subjects were asked to provide a global rating of their overall expectation for each examination (Not Unpleasant, A Little Unpleasant,
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Somewhat Unpleasant, Very Unpleasant, or Extremely Unpleasant). At time 2, conducted just after completion of the CT test and before the colonoscopy examination, subjects were asked to rate their experiences regarding that examination. Subjects rated their posttest appraisals of the CT test using the same scales used to rate expectations at time 1. The main purpose of the time 2 CT colonography immediate posttesting assessment was to confirm stability in the measurements with time 3, the major postappraisal assessment. At time 3, subjects were contacted by telephone by the interviewer within 2 to 3 days after the examinations to assess their posttesting comparative appraisals of both CT and colonoscopy. Once again, subjects rated the amount of Pain or Discomfort, Embarrassment, and Difficulty that they experienced with CT, whether any of those experiences would be significant enough to decrease their willingness to have the examination performed in the future, and they provided a global rating of their overall appraisal of the examination. In addition, subjects were asked, “In the future, which test would you prefer to have done?” (CT, Colonoscopy, No Preference). Those subjects who expressed a preference for one examination over the other were then asked, “How much did you prefer the ________ to the __________?” (A Slight Preference, A Moderate Preference, A Strong Preference, or A Very Strong Preference). Subjects were also asked questions about the bowel preparation, because it is one common feature of both CT and colonoscopy examinations and also one aspect of testing toward which subjects typically have their most negative reaction. The same questions were asked regarding the bowel preparation at both time 1 and time 3. Subjects were asked about their overall reaction to the bowel preparation (Not Unpleasant, A Little Unpleasant, Somewhat Unpleasant, Very Unpleasant, or Extremely Unpleasant). Subjects were also asked how much they might have disliked different aspects of the bowel preparation (i.e., the liquid diet, drinking the fluid, making frequent trips to the bathroom) by rating their dislike of each of these features on multiple choice scales (Not At All, A Little, Moderately, A Lot, or Extremely). Finally, at time 3, subjects were asked to appraise miscellaneous features of the two examinations, including Pain, Sedation, and Lost Time. Subjects were asked how much they might have disliked Pain or Lost Time, and how much either of those features might decrease their willingness to have testing in the future. Regarding sedation, subjects were asked whether (and how much) sedation might either increase or decrease their willingness to have testing in the future. Statistical Analysis Comparisons of reactions to air versus CO2 techniques at CT colonography were evaluated for differences. When no significant differences were found between CT techniques,
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CT results collectively (air and CO2) were then compared to colonoscopy results in the following: expectations for CT versus colonoscopy and reactions before versus after to CT and colonoscopy, respectively. Comparisons of the overall appraisals of the bowel preparation, CT, and colonoscopy were also performed. All comparisons were tested for statistical significance using the Wilcoxon signed ranks test for two reasons. First, all comparisons were paired within subjects, either comparisons between the two examination types at the same point in time or comparisons of the same examination at two points in time. Second, most of the distributions were strongly skewed in the positive direction, thus violating a principal parametric assumption. The Wilcoxon signed ranks test was chosen because of its sensitivity to the magnitude of differences between two paired variables, to glean the most information possible from these data (21). All tests were two-tailed, and statistical significance was defined as p ⬍ 0.05.
RESULTS Randomization and Patient History Of the subjects, 67 (55.8%) were female (33 air and 34 CO2) and 53 (44.2%) were male (26 air and 27 CO2). The mean (⫾ SD) age was 58 ⫾ 8.2 yr (range 38 –75 yr). Also, 94 (78.3%) were Caucasian, 24 (20.0%) were African American, and two (1.7%) were Asian. Results of patients’ GI history, collected by the study coordinator on the day of the CT examination, demonstrated the following incidence of: 27/120 (22.5%) prior GI surgery, 14/120 (11.7%) use of laxatives, four of 120 (3.3%) irritable bowel syndrome, one of 120 (0.8%) pelvic floor relaxation, six of 120 (5.0%) diverticular disease. Pre-examination Expectations Versus Postexamination Appraisals Subjects’ ratings of both examinations, taken both before and after they were done, are shown in Table 1. Subjects’ comparative expectations for the two examinations were assessed at time 1. As can be seen, subjects expected to experience more pain with colonoscopy than with CT, and this difference was statistically significant (z ⫽ ⫺2.371, p ⬍ 0.05). However, the differences occurred primarily between ratings of “A Little” and “Moderate,” so subjects did not expect too much pain with either test. Subjects also expected more embarrassment with colonoscopy (z ⫽ ⫺2.489, p ⬍ 0.05), although again the shifts occurred at the lower end of the scale. Subjects expected more difficulty with colonoscopy compared to CT, although this difference was not significant (z ⫽ ⫺1.644, p ⫽ 0.10). Overall, subjects expected the colonoscopy to be more unpleasant than CT (z ⫽ ⫺1.998, p ⬍ 0.05). At time 3, performed by telephone interview within 2 to 3 days after the examinations, subjects were asked to appraise the two examinations, which made it possible to compare their pretest expectations with their posttest ap-
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Table 1. Comparisons Between Spiral CT and Colonoscopy Spiral CT
Colonoscopy
Pre Post Pre Post (n ⫽ 120) (n ⫽ 120) (n ⫽ 120) (n ⫽ 120) Pain/discomfort None A little Moderate A lot Extreme Embarrassment None A little Moderate A lot Extreme Difficulty None A little Moderate A lot Extreme Overall (“Unpleasant”) Not A little Somewhat Very Extremely
0.28 0.53 0.15 0.04 0.00
0.39 0.48 0.11 0.02 0.00
0.26 0.41 0.27 0.06 0.01
0.84 0.12 0.02 0.02 0.00
0.58 0.29 0.08 0.02 0.02
0.69 0.26 0.04 0.01 0.00
0.50 0.33 0.11 0.04 0.02
0.93 0.07 0.00 0.00 0.00
0.66 0.27 0.06 0.01 0.01
0.82 0.17 0.02 0.00 0.00
0.58 0.33 0.08 0.02 0.00
0.97 0.03 0.00 0.00 0.00
0.21 0.59 0.18 0.02 0.01
0.57 0.38 0.05 0.00 0.00
0.21 0.45 0.32 0.02 0.00
0.68 0.28 0.04 0.00 0.01
praisals. Compared to their expectations, subjects generally found CT at time 3 to be somewhat less painful (z ⫽ ⫺1.890, p ⫽ 0.06), as well as significantly less embarrassing (z ⫽ ⫺3.121, p ⬍ 0.005), less difficult (z ⫽ ⫺3.169, p ⬍ 0.005), and less unpleasant overall (z ⫽ ⫺5.854, p ⬍ 0.001). Parenthetically, subjects’ appraisals of CT at time 2, measured immediately after the CT and before colonoscopy, were very similar to appraisals measured at time 3 by telephone interview 2 to 3 days after both examinations. The one difference that emerged was that subjects reported lower levels of pain/discomfort at time 3 compared to time 2 (z ⫽ ⫺3.703, p ⬍ 0.001). The main purpose of time 2 testing was to assess stability of the assessments immediately after CT compared to 2 to 3 days after CT. Compared to expectations regarding colonoscopy, subjects found the actual examination at time 3 to be less painful (z ⫽ ⫺7.420, p ⬍ 0.001), less embarrassing (z ⫽ ⫺6.667, p ⬍ 0.001), less difficult (z ⫽ ⫺6.195, p ⬍ 0.001), and less unpleasant overall (z ⫽ ⫺7.112, p ⬍ 0.001). Postexamination appraisals obtained at time 3 allowed comparisons between the two tests regarding actual experiences. Time 3 was the major postappraisal assessment for both CT and colonoscopy, as it was believed to be the best assessment of colonoscopy after full recovery from medications. As can be seen, subjects tended to have more favorable reactions to colonoscopy in terms of pain (z ⫽ ⫺6.024, p ⬍ 0.001), embarrassment (z ⫽ ⫺4.957, p ⬍ 0.001), and difficulty (z ⫽ ⫺3.911, p ⬍ 0.001). It is important to note, however, that most of the ratings of both
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tests were either in the “None” or “A Little” categories. Also, subjects did not view the two tests to be significantly different in the overall ratings (z ⫽ ⫺1.434, ns). Finally, analyses were conducted to investigate whether there were differences in ratings of the two examinations according to the sex of the patient, and three differences were found regarding pre-examination expectations. Women expected greater pain and discomfort with the CT colonography compared to men (z ⫽ ⫺1.994, p ⫽ 0.046). Women also gave more negative overall expectations than men for both CT (z ⫽ ⫺2.375, p ⫽ 0.018) and colonoscopy (z ⫽ ⫺2.294, p ⫽ 0.022). Interestingly, there were no gender differences found for any of the postexamination appraisal ratings. Overall Preferences (Future Tests) With regard to overall preferences for the two screening tests, 69 (57.5%) of the subjects preferred CT, 17 (14.2%) preferred colonoscopy, and 34 (28.3%) stated that they had no preference. For those subjects who reported a preference, the magnitude of that preference was measured. Of the 69 subjects who preferred the CT examination, the preference was Slight for 11 (15.9%), Moderate for 13 (18.8%), Strong for 27 (39.1%), and Very Strong for 18 (26.1%). Of the 17 subjects who preferred the colonoscopy, the preference was Slight for four (23.5%), Moderate for five (29.4%), Strong for four (23.5%), and Very Strong for four (23.5%). The difference in magnitude of the preferences was not significant. Because initial analyses revealed a clear disparity between the posttest comparative appraisals of the two tests and the global preference ratings, another question was added to the time 3 interview for the last 47 subjects. After stating their global preference for testing, these subjects were asked the open-ended question: “Why do you feel this way?” Of these 47 subjects, 25 subjects preferred CT, seven preferred colonoscopy, and 15 stated that they had no clear preference. The general feeling among the 25 subjects who preferred the CT examination was that it was quicker, easier, less invasive, and did not require sedation. For the seven subjects who preferred colonoscopy, they either liked the fact that there was only one test or that they could “sleep through” the procedure. Bowel Preparation Subjects indicated their reactions to the bowel preparation at both time 1 and time 3, as shown in Table 2. Two trends are worth noting about these data. First, subjects were able to discriminate among the listed features of the preparation in terms of unpleasantness. Subjects reported that drinking the fluid was the most unpleasant aspect of the preparation. Of note, based on the participating gastroenterologists’ recommendations, most of the subjects (n ⫽ 109) received Phospha-Soda, whereas the remaining subjects (n ⫽ 11) received GoLytely. Subjects reported that drinking the fluid was more unpleasant than having to take frequent trips to the
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Table 2. Bowel Preparation Appraisal Time 1 (n ⫽ 120)
Time 3 (n ⫽ 120)
Liquid diet (“How much did you dislike. . .) Not at all 0.18 0.44 A little 0.44 0.25 Moderately 0.25 0.20 A lot 0.08 0.08 Extremely 0.05 0.03 Drinking the fluid (“How much did you dislike. . .) Not at all 0.11 0.19 A little 0.31 0.25 Moderately 0.20 0.22 A lot 0.23 0.16 Extremely 0.15 0.18 Frequent trips to the bathroom (“How much did you dislike. . .) Not at all 0.09 0.22 A little 0.31 0.34 Moderately 0.30 0.20 A lot 0.23 0.16 Extremely 0.07 0.08 “How much would the bowel preparation decrease your willingness to have either test?” Not at all 0.55 0.81 Slightly 0.24 0.10 Moderately 0.13 0.08 A lot 0.05 0.01 Would refuse 0.01 0.00
bathroom (time 1: z ⫽ ⫺1.059, p ⫽ 0.290; time 3: z ⫽ ⫺2.764, p ⬍ 0.01), which was in turn more unpleasant than having to be on a liquid diet (time 1: z ⫽ ⫺4.490, p ⬍ 0.001; time 3: z ⫽ ⫺3.755, p ⬍ 0.001). The second trend worth noting is that subjects tended to give less negative ratings of these features at time 3 compared to time 1. This trend was statistically significant with regard to the liquid diet (z ⫽ ⫺3.920, p ⬍ 0.001) and having to take frequent trips to the bathroom (z ⫽ ⫺3.240, p ⬍ 0.001). Most importantly, subjects’ judgments of the negative impact that the bowel preparation would have on their willingness to have either type of examination in the future also lessened between time 1 and time 3 (z ⫽ ⫺4.528, p ⬍ 0.001). At time 3, subjects gave overall assessments of each of the two screening examinations and the bowel preparation. As can be seen in Table 3, subjects clearly responded much more negatively to the bowel preparation process than to either of the two examinations. They found the bowel preparation to be significantly more unpleasant than both the CT (z ⫽ ⫺8.272, p ⬍ 0.001) and the colonoscopy (z ⫽ ⫺8.324, Table 3. Overall Appraisals (Time 3) of Bowel Preparation, CT, and Colonoscopy Preparation (n ⫽ 120) Not unpleasant A little unpleasant Somewhat unpleasant Very unpleasant Extremely unpleasant
0.12 0.27 0.38 0.17 0.07
CT Colonoscopy (n ⫽ 120) (n ⫽ 120) 0.57 0.38 0.05 0.00 0.00
0.68 0.28 0.04 0.00 0.01
p ⬍ 0.001). Lastly, subjects were asked whether there was anything about either of the two examination techniques that would decrease their willingness to have it done in the future. Regarding spiral CT, one subject indicated that “Discomfort” would decrease their willingness “slightly,” a second subject indicated that having “Radiation” would decrease their willingness “moderately,” and a third subject indicated that “Wearing the gown” would decrease their willingness “slightly.” Regarding colonoscopy, one subject indicated that having the i.v. would decrease their willingness “a lot.” On the other hand, when subjects were asked whether the bowel preparation would decrease their willingness to have either of the two examinations, 23 of the 120 subjects said “yes” (12 patients “slightly,” 10 “moderately,” and one “a lot”).
DISCUSSION A key challenge to increasing rates of participation in colorectal cancer screening will be to minimize logistic and psychological barriers. Clearer guidelines for screening, along with broader coverage by health insurers, have lowered some of those barriers. However, significant psychological barriers still remain. The development and refinement of screening technologies must be done with these issues in mind, so that progress can be made in the direction of greater public acceptance and, therefore, greater participation. Spiral CT colonography has the potential to lower some of these psychological barriers by providing a procedure that is less invasive and quicker compared to colonoscopy and does not require sedation. In this prospective study of CT colonography (air vs CO2 insufflation techniques) compared to conventional colonoscopy, we determined the following key findings. Pre-examination expectations were more negative for both CT and colonoscopy compared to postexamination appraisals for each examination; specifically, more negative pre-examination expectations were reported for colonoscopy than CT. Postexamination appraisals were similar comparing manual insufflation of air to manual insufflation of CO2 at CT colonography. Postexamination appraisals of CT (air and CO2) were more negative than colonoscopy in pain and discomfort; however, the majority of the responses were of minimal ratings. Comparing the postexamination appraisals of overall unpleasantness, the bowel preparation had significantly higher scores than either the CT or the colonoscopy examinations. Preferences for future testing demonstrated that patients would prefer CT colonography to conventional colonoscopy. To date, very few studies have looked at patients’ attitudes toward spiral CT colonography, with mixed results. Angtuaco et al. conducted a survey study of community members and physicians who were asked to state their preferences for spiral CT compared to colonoscopy (22). In general, potential patients preferred the CT to the colonoscopy, whereas physicians preferred colonoscopy. However,
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this study was based only on subjects’ preferences when presented with the hypothetical possibility of screening. Also, only about 20% of the subjects in this study were aged ⱖ 50 yr, the group for whom screening recommendations are most pertinent. Several preliminary investigations have evaluated assessments of patients who have undergone both CT colonography and colonoscopy. Forbes and Mendelson (23) studied 70 patients and determined that subjects judged the two examinations to be essentially comparable in terms of pain, embarrassment, tolerability, and overall preference. Pineau et al. (24) studied 55 patients and reported preprocedural expectations to be more positive toward CT than conventional colonoscopy. After both procedures, there were no differences in patient perceptions of the two tests, but patients preferred CT colonography for future testing. Farrell et al. (25) reported a study of 100 patients and found similar discomfort and pain scores between CT and colonoscopy at two time points. Akerkar et al. (26) conducted the largest study to date in a cohort of 295 veterans (287 men and eight women, average age 62.4 yr) from the Department of Veterans Affairs. All patients underwent CT colonography approximately 2 to 3 h before undergoing conventional colonoscopy. CT colonography was performed without medications or bowel relaxants, using manual insufflation of room air (30 – 40 bulb compressions). Conventional colonoscopy was performed with routine conscious sedation using i.v. pain and sedative medications. Data were obtained immediately after each examination and 24 h later. Using a seven-point Likert scale, patients reported more pain, more discomfort, and less respect with CT compared to colonoscopy at both time points. Using the time-tradeoff technique, patients stated that they preferred colonoscopy to CT and would be more willing to wait longer to undergo colonoscopy than undergo a CT colonography examination. The preference for colonoscopy with future testing in the Akerkar et al. study markedly contrasts with our study results regarding preference for CT colonoscopy. Differences in our study included a more balanced cohort of men and women, postexamination appraisal data collection at 1–3 days after each examination (rather than during the recovery period from conscious sedation), and use of comparative ratings rather than time-tradeoff techniques for preference in future testing. In our investigation, pre-examination expectations for conventional colonoscopy were worse than for CT colonography in terms of pain, embarrassment, and overall unpleasantness. These expectations may have been due in part to the more invasive nature of endoscopy and a lack of understanding of the effectiveness of medications for pain and sedation. On the other hand, postexamination appraisals of colonoscopy (with analgesic, sedative, and GI relaxant medications) were better than for CT colonography (with no medications), in terms of pain, embarrassment, and difficulty. These results certainly demonstrate that colonoscopy is well tolerated with appropriate medication. However, CT colonography was also performed with acceptable patient
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tolerance measured postexamination with no medications. For both colonoscopy and CT, postexamination appraisals improved compared to pre-examination expectations. There were no ratings that were more negative at the subsequent time point. In addition, less negative ratings of the pain and discomfort at CT colonography were found at time 3 (2 to 3 days after both examinations) than at time 2 (directly after CT and before colonoscopy). This pattern indicates a trend toward tempering of adverse reactions to the CT examination over the short time course of only 2 to 3 days, with the perspective of having undergone both CT and colonoscopy. This is an important trend to note for future evaluations, to arrive at the best estimate of assessments that would be more likely to influence subsequent behaviors. That is, postexamination appraisals might be more predictive of future behaviors if they are obtained at 2 to 3 days after the procedure, after patients have fully returned to normal functioning. One of the most important findings of this study was the markedly negative appraisal of the bowel preparation. The bowel preparation, currently common to both CT colonography and colonoscopy, was clearly rated as the most unpleasant of all aspects of the testing procedure. This finding seems especially important, given the magnitude of the differences in ratings given when subjects compared the bowel preparation procedure to the two screening examinations per se. Of the individual components of the bowel preparation, drinking the fluid was the most unpleasant, followed by frequent trips to the bathroom and, finally, the liquid diet. Again noted, these ratings were less negative a few days after all procedures, compared to appraisals on the morning after the bowel preparation. These findings regarding the bowel preparation will be essential to incorporate into future technical developments of dietary recommendations and cathartic regimens before GI screening examinations. Preliminary work in stool tagging and subtraction in CT colonography has shown promising results (27, 28). Such efforts could prove to be extremely valuable in improving both image quality and patient acceptance. Several influences of our CT methods are important to recognize. For both air and CO2 insufflation techniques at CT colonography, the total gas instilled by the radiologist was influenced both by how the patient was tolerating the procedure and by judging whether adequate colonic distention was seen in the images. Our use of manual methods of insufflation is another important factor. Although the automated insufflation technique with CO2 was initially used, there was variable success in patients with tortuous colons or retained fluid. Thus, to eliminate the additional influence of method of insufflation, the comparison between air and CO2 was changed to use manual insufflation techniques for both. More CO2 was generally given than air because of the faster absorption rate of CO2. Although we found no differences between manual methods of air and CO2 insufflation techniques, further evaluation with automated insufflation techniques may be warranted. Finally, no GI relaxants
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were given to patients at CT colonography in this investigation. This was based on the controversial benefit previously reported with the use of glucagon (29). In our prior experiences, we have used both Glucagon and Robinol; however, we experienced only a marginal improvement in colonic insufflation in these patients, sometimes at the expense of patient dissatisfaction to an i.v. injection or overinsufflation of the small bowel. Buscopan has been used in Europe with reported success; however, approval of its use in the United States has not been given by the Food and Drug Administration. More effective use of GI relaxants in future investigations of CT colonography could certainly improve patient tolerance and bowel insufflation. Finally, our study cohort and methods of patient preference assessments are important influences to consider. In the subject sample studied here, the distributions of age, sex, and ethnicity are comparable to those that would likely be seen in a population presenting for colon screening. It is thus unlikely that the results are influenced by any systematic artifacts of nonrepresentative demographics. One important influence for which we did not control in this study cohort was the potential bias imparted in some subjects who may have had prior colorectal screening examinations such as flexible sigmoidoscopy (30), barium enema, or colonoscopy. In these patients, previous good or bad experiences may have affected both their expectations before and their appraisals afterward. Other potential influences in this cohort were the added personal attention (with regard to any pain, discomfort, or embarrassment that they may have experienced) and monetary compensation provided as part of a carefully controlled research protocol. Because of these factors, subjects may have responded more favorably overall. With regard to the questionnaires that were used, it is important to note that the majority of ratings were on the lower end of the scales (e.g., “None” to “A little”). This suggests that subjects may have minimized any negative reactions to the two examinations, thus making finer discriminations difficult. However, the fact that the ratings of the bowel preparation showed more even distributions across the scales, extending much more into the negative end of the scale, indicates that the ratings given to the examinations per se were probably placed appropriately in the larger context of the entire experience. Finally, the paradoxical trend in preference for CT colonography in future testing (despite more negative CT assessments) may indicate that some patients were basing their future preferences on influences beyond those that were measured. The last 47 subjects indicated that their future preferences for CT were based on the quick, easy, and noninvasive nature of the examination. We can only speculate about other possible influences on future preferences for CT. Those might include the perception that CT is a more “high tech” procedure and the “wave of the future,” thus making it more desirable for future testing. In summary, this prospective study of CT colonography and colonoscopy demonstrated less favorable pre-examina-
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tion expectations but more favorable postexamination appraisals for colonoscopy. However, overall CT colonography received excellent postexamination appraisals and was preferred for future evaluations. The bowel preparation received significantly less favorable appraisals than either CT colonography or conventional colonoscopy. Efforts to improve methods of catharsis and dietary restrictions will be critical in directing future investigations. The resulting assessments of patient acceptance will then need to be included. To those ends, effective efforts aimed at decreasing current barriers to public acceptance could have a significant positive impact on the early detection of colorectal cancer.
ACKNOWLEDGMENTS This research was supported by National Institutes of Health grant N01 CN25516 to Elizabeth G. McFarland, M.D., and as a subcontract of the National Cancer Institute ProstateLung-Colon-Ovary Screening Trial (N01-CN-25516). We appreciate the support by Gerald Andriole, M.D., who is the Principal Investigator of the PLCO at Washington University School of Medicine. We acknowledge the help provided by the CT technologists at Barnes Jewish hospital of Mallinckrodt Institute of Radiology. We also greatly appreciate the thorough efforts of our dedicated study coordinator, Robin Haverman. Reprint requests and correspondence: Stephen L. Ristvedt, Ph.D., Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Avenue, St. Louis, MO 63110-1093. Received May 30, 2002; accepted Aug. 26, 2002.
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