- Email: [email protected]
A comparison of four screening methods for cervical neoplasia in a developing country
A comparison of four screening methods for cervical neoplasia in a developing country Hendrik S. Cronjé, MD,a Groesbeck P. Parham, MD,b Bruno F. Cooreman, FCOG,a Amanda de Beer, MMed,c Peter Divall, CFIAC,c and Roosmarie H. Bam, MBCHBa Little Rock, Ark, and Bloemfontein, South Africa OBJECTIVE: The purpose of this study was to compare the results of cytologic examination, cervicography, direct acetic acid test, and magnified acetic acid test (speculoscopy) with the results of histologic examination. STUDY DESIGN: The study was a prospective, descriptive, and analytic study that included 1286 women in a primary health facility who were screened by cytologic examination, cervicography, direct acetic acid test, and magnified acetic acid test (speculoscopy). Histologic evidence was obtained on all patients by means of cervical punch biopsies. The biopsy specimens were taken from aceto-white areas or areas suspicious of cancer. In normal individuals, the specimens were taken from the external cervical os at the 12 or 6 o’clock position, whichever was most convenient. Positive cases were treated by colposcopy and large loop excision of the transformation zone. Testing for human immunodeficiency virus infection was not done. RESULTS: Of the 1286 women who were screened, 1093 women (85%) were eligible for analysis. The mean age of the women was 38.6 years. Because histologic evidence was obtained on all women, direct sensitivities and specificities could be calculated for each screening method. The sensitivity, specificity, and positive predictive values for cytologic examination were 53%, 95%, and 47%, respectively; for cervicography were 49%, 88%, and 26%, respectively; for the direct acetic acid test were 79%, 49%, and 12%, respectively; and for speculoscopy were 77%, 45%, and 11%, respectively. Of the 876 patients who were eligible for colposcopy, only 468 women (56%) eventually returned for colposcopy. CONCLUSION: Cytologic examination, cervicography, the direct acetic acid test, and speculoscopy are not suited for screening in developing countries because of the low sensitivity of the cytologic examination and the low specificity of the other tests. Two or more tests combined will increase the sensitivity, but the specificity remains low. Screening methods in developing countries remain an urgent problem. (Am J Obstet Gynecol 2003;188:395-400.)
Key words: Screening, cervix, cytologic examination, cervicography, direct acetic acid test, speculoscopy
Cancer of the cervix is the most common malignancy in women in developing countries.1 At our institution, one in four patients with cancer (including children and men) is a woman with cancer of the cervix. Furthermore, the lifetime risk for a woman in South Africa for the development of this type of cancer is 1:26.2 This high prevalence is attributed mainly to a lack of screening, particularly in women of low income.3 From the Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Arkansas,b and the Departments of Obstetrics and Gynecologya and Anatomical Pathology and Cytology,c University of the Free State. Supported by the Medical Research Council (Bellville, South Africa) and by the Trylon Corporation (Torrance, Calif). Received for publication February 12, 2002; revised August 29, 2002; accepted September 27, 2002. Reprint requests: H. S. Cronjé, MD, Department of Obstetrics and Gynecology (G71), PO Box 339, Bloemfontein 9300, South Africa. E-mail: [email protected] © 2003, Mosby, Inc. All rights reserved. 0002-9378/2003 $30.00 + 0 doi:10.1067/mob.2003.153
Notwithstanding an enormous amount of research on screening for cervical neoplasia in developing countries, little progress has been made.1 In Africa, no country has managed to conduct sustainable large population-based screening programs. Chile is the only country in South America with a successful mass screening program, and only a few countries in Asia have been able to make significant progress with cervical screening. Even in a highly developed country such as the United States, an unexpectedly large number of infiltrating cervical cancers are diagnosed each year.1 The generally accepted cytologic smear of the cervix (Papanicolaou test) has certain disadvantages. It has a low sensitivity (often <50%4-6); expertise is needed to take and evaluate the specimens; and it is fairly expensive and does not provide an immediate result, so that women must return at a later date for the report. In developing countries, many women are lost in this process.3 In a developing country, the ideal screening test should be inexpensive; have a high sensitivity, specificity, and 395
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Table I. Characteristics of screening tests Screening test
Characteristic Threshold for positive screening result Threshold for positive histologic results Sensitivity (%) Specificity (%) Positive predictive value Negative predictive value
Cytologic examination
Cervicography
Direct AAT
Speculoscopy
≥LSIL ≥CIN II 53.3 94.6 47.1 95.7
≥Positive grade 1* ≥CIN II 48.9 87.5 26.0 95.0
White lesion or cancer ≥CIN II 78.9 48.9 12.2 96.3
White lesion or cancer ≥CIN II 76.7 44.6 11.0 95.5
*Condyloma and CIN I.
positive predictive value; and be relatively easy to evaluate and should provide an immediate result. Furthermore, it should also be acceptable to both the female clients and health care workers. In view of these prerequisites, we compared the cytologic test and cervicography, the direct acetic acid test (AAT) and the magnified AAT (speculoscopy). Our specific aim was to discover new possibilities for screening women in a developing country. Material and methods This study was approved by the Ethics Committee of the Faculty of Health Sciences, University of the Free State, South Africa, and was performed in accordance with the ethical standards set by the Declaration of Helsinki (1975, revised 1983). It was conducted in a large primary health care clinic at Pelonomi Hospital, one of our teaching institutions. Women who attended this clinic for any kind of ailment or disease were offered screening by means of a Papanicolaou test. When the woman accepted the offer, the study was explained to her by one of our study nurses (both professional nurses). If she refused the offer after the study had been explained, only a Papanicolaou test was taken, and she was excluded from further participation in the study. Inclusion criteria included women who were ≥30 years (although for ethical reasons we did not exclude younger women who spontaneously requested a Papanicolaou test) with an intact uterus. Exclusion criteria included previous cervical screening, pregnancy, heavy vaginal bleeding, and severe vaginitis or cervicitis. In total, 1286 women were included over an 18-month period. After giving informed consent, each woman was subjected to four screening tests that were performed by a professional nurse, in the following order: cytologic examination, cervicography, direct AAT, and speculoscopy. The nurse was a professional nurse who had been trained specially in the techniques of the different screening tests. After the last of these four tests, a punch biopsy (for histologic purposes) was taken from any acetowhite lesion on the cervix, if identified during the AAT or speculoscopy. In the absence of a visible acetowhite lesion, the biopsy specimen was taken from the external os, at either
the 12 o’clock or the 6 o’clock position, whichever was the most convenient. In addition, a biopsy specimen was taken from any lesion that was suggestive of cancer. The cytologic smear was taken with a Cervex-brush (Medscamp Med AD, Malmö, Sweden), which samples both the ectocervical and endocervical components, and was fixated on a glass slide with Cytological Fixative (Fencott, Sangene Products, Cape Town, South Africa). The slides were stained according to the Papanicolaou method and examined in the Department of Cytology, Faculty of Health Sciences, University of the Free State. Cervicography was performed with a Cerviscope (National Testing Laboratories Worldwide, St Louis, Mo). The slides were developed locally and evaluated by two of the authors who are United States–certified evaluators of cervicography (H. S. C. and B. F. C.) without knowledge of the results of any of the other tests. A cotton wool swab was soaked in a 5% acetic acid solution and gently pressed against the cervix for 30 seconds. The swab was removed, and the procedure was repeated with a second soaked swab. Thereafter, the first cervicography photograph was taken; after a third application of 5% acetic acid, the second photograph was taken. One of the study nurses then performed the direct AAT, which comprised a careful naked eye examination of the cervix for the presence of an acetowhite lesion or signs of infiltrating cancer. Speculoscopy was done immediately after the direct AAT but was always performed by the second nurse without knowledge of the direct AAT diagnosis made by the first nurse. A Speculite (Trylon Corporation, Torrance, Calif) was applied to the inside of the upper blade of the Cusco speculum after having been bent sharply, which resulted in the formation of a chemiluminescent light near the cervix. With the room darkened, the nurse examined the cervix with the aid of surgical loupes (magnification, 4) for the presence of an acetowhite lesion or signs of infiltrating cancer (Gynoscope; Perisphere Industries Inc, Torrance, Calif). After the fourth screening test, an Eppendorfer cervical biopsy forceps (BEI Medical Systems Inc, Gembloux, Belgium) was used to obtain a cervical punch biopsy specimen, as described earlier. The specimen was preserved
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Table II. Histologic results for patients with positive screening test results and the results of the random punch biopsy specimens Histologic results (n) Screening test Cytologic examination (n = 89) Cervicography (n = 235) Direct AAT (n = 583) Speculoscopy (n = 624) Random biopsy (n = 413)*
Negative
Atypia
CIN I
CIN II
Infiltrating cancer
2 (2.2%) 20 (8.5%) 104 (17.8%) 121 (19.4%) 56 (13.6%)
19 (21.3%) 84 (35.8%) 239 (41.0%) 267 (42.8%) 237 (57.4%)
23 (25.9%) 81 (34.5%) 169 (29.0%) 167 (26.8%) 103 (24.9%)
37 (41.6%) 41 (17.4%) 62 (10.6%) 60 (9.6%) 17 (4.1%)
8 (9.0%) 9 (3.8%) 9 (1.5%) 9 (1.4%) 0 (0%)
*These biopsy specimens were taken when the direct AAT and/or speculoscopy results were negative.
in 10% formal-saline solution and examined in the Department of Anatomical Pathology by one of the authors (A. deB.). If a patient had >1 histologic diagnosis (eg, a punch biopsy and an excisional biopsy), the one with the most severe degree of pathologic features was used in the analysis. Both the Papanicolaou tests and the biopsy specimens were evaluated without the knowledge of the results of the other tests. Patients with the following results were referred for colposcopy: (1) atypia of squamous cells of undetermined significance (ASCUS) or more severe pathologic features on cytologic examination, (2) all positive cervicography categories, (3) acetowhite lesions or possible cancer on the direct AAT or speculoscopy, and (4) condyloma, cervical intraepithelial lesion (CIN), or infiltrating cancer on histologic examination (punch biopsy). Two experienced colposcopists (H. S. C. and B. F. C.) performed the colposcopies. Biopsy-proved CIN lesions were treated by large loop excision of the transformation zone with the use of a Finesse II (Utah Medical Products, Midvale, Utah) electrosurgical apparatus. Infiltrating lesions were treated according to the standard protocol of the department. Descriptive statistics and 2--2 tables were generated with the EpiInfo 6 (version 6.02) statistical program (Centers for Disease Control and Prevention, Atlanta, Ga). Results In 193 of the 1286 women (15%) who were included in the study, at least one test result was defective or unavailable, which left the results of 1093 women (85%) that were eligible for analysis. The mean age of these women was 38.6 years (median, 38.0 years), with a range of 21 to 65 years. Only 12% were <30 years of age. The mean parity was 2.5 (median, 2.0), with a range of 0 to 11. Contraception was used by 30.8% of the patients, with an additional 14.3% having undergone sterilization. Smoking was reported by 17.2% of the women, and the use of snuff (inhaling of tobacco powder) was reported by 24.4% women. Two thirds of the women (728/1093 women) returned for their results. Of these, 604 women (83%) were re-
ferred for further evaluation, of whom 468 women (78%) returned for colposcopy and possible treatment. The 468 women who eventually returned for colposcopy represented 56% of the 876 women who originally met the established criteria for colposcopic evaluation. The cytologic examination results were as follows (n = 1093 women): negative, 960 women (87.8%); ASCUS or AGUS, 31 women (2.8%); low-grade squamous intraepithelial lesion (LSIL), 39 women (3.6%); HSIL, 52 women (4.7%), and infiltrating cancer, 11 women (1.0%). In Table I, a summary is given of the cytologic examination’s sensitivity and other characteristics. Cervicography’s results were as follows (n = 1093 women): negative, 748 women (68.4%); atypical, 110 women (10.1%); P0, 36 women (3.3%); positive grade 1, 156 women (14.3%); P2, 34 women (3.1%); and infiltrating cancer (P3), 9 women (0.8%). Positive grade 0 means probably negative, but colposcopy and biopsy are needed for the exclusion of cancer; positive grades 1 and 2 are LSIL and HSIL, respectively; and positive grade 3 indicates infiltrating cancer. The different characteristics of cervicography are also shown in Table I. The direct AAT was negative in 510 cases (46.7%); an acetowhite lesion was noted in 577 cases (52.8%), and possible cancer was noted in 6 cases (0.5%, n = 1093 women). Speculoscopy’s results were negative in 468 women (42.8%); an acetowhite lesion was noted in 617 women (56.5%), and possible cancer was noted in 8 women (0.7%, n = 1093 women). The characteristics are summarized in Table I. Histologic results of the cervical punch biopsy specimens (which were obtained at the time of screening) and the excisional biopsy specimens (which were obtained during colposcopic evaluation) were as follows (n = 1093 women): negative, 183 cases (16.7%); atypia, 3 cases (0.3%); koilocytosis, 346 cases (31.7%); condyloma, 179 cases (16.4%); CIN I, 292 cases (26.7%); CIN II, 50 cases (4.6%); CIN III, 31 cases (2.8%); and infiltrating cancer, in 9 cases (0.8%). If a patient had >1 histologic result (eg, a punch biopsy and an excisional biopsy), the most severe result was documented here. In Table II, the histologic results of patients with positive screening tests are shown.
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Table II includes the results of the punch biopsy specimens that were taken from patients who had no visible acetowhite lesion at the initial screening. Comment In this study, the sample was taken from a population of clinic attenders. Realizing that this population was not similar to the general population, we still considered it acceptable because of the availability of women to be screened and an expected higher prevalence of cervical neoplasia. Whether this selection influenced the sensitivity of the different tests is uncertain. The mean age of the patients in this study was higher when compared with most other studies of this kind: 38.6 years versus 34.1 years and 28.0 years in the reports of Wertlake et al4 (United States) and Olatunbosun et al5 (Africa). We used 30 years as the minimum age for inclusion because, by that age, most of the minor lesions (ASCUS and even LSIL) would have regressed.6 After 30 years, we also expected a lower prevalence and a lesser degree of cervicitis. However, younger women who turned up at the screening clinic requesting cervical screening were not refused. This approach resulted in the rather older mean age, where a high prevalence of high-grade disease can be expected. Indeed, in our population 8.2% of patients had histologically proven HSIL and cancer, an extremely high prevalence. The sensitivity of cytologic examination is a subject of debate. In an excellent review, Fahey et al7 reported a sensitivity of 58% and a specificity of 69%. The authors pointed out that unless histologic condition (the gold standard or reference test) is determined on all screening negatives in addition to the screening positives, the sensitivity will be unrealistically high.7 This statement was confirmed in more recent reviews of the sensitivity of cytologic examination.8,9 In the comprehensive review by McCrory et al,8 the sensitivity of cytologic examination in the least-biased studies was found to be 51%, with a 95% CI of 37%-66%. However, it was emphasized that the new techniques in cytologic examination (thin layer cytologic examination and computerized rescreening) were associated with an increased sensitivity. Nanda et al9 expanded the study by McCrory et al and found that for the nine studies that reported an LSIL/CIN-I threshold in a lowrisk population, sensitivity ranged from 30% to 87% (mean, 47%; median, 42%; <60% in eight of these studies). As expected, for the HSIL/CIN-II-III threshold, the sensitivity was higher and ranged from 44% to 99% (mean, 71%; median 68.5%). In our study it was 53%, with the use of an LSIL threshold for cytologic examination and CIN II for histologic examination. In a developing country, the number of screening events per woman per lifetime has to be restricted because of cost constraints, compliance, and coverage. The World Health Organization proposed a policy of at least
February 2003 Am J Obstet Gynecol
one cytologic test at the age of 35 to 40 years.1 In South Africa, the government approved a policy of three tests per lifetime, starting at age 30 years, with 10-year intervals. When the number of screening events per lifetime is reduced, the sensitivity of the screening test has to be increased. Cytologic examination, with its relatively low sensitivity, is certainly not a viable option within such a scenario. The new technologies in cytologic examination (thin-layer cytologic examination and computerized rescreening) may be a viable alternative that must be considered. The developmental phase of cervical neoplasia covers ≥2 decades, starting with atypia and LSIL and terminating in cancer.4 It seems unlikely for a woman to have the first preinvasive changes on the cervix, which can lead ultimately to invasive cancer after 30 or 35 years of age. Therefore, if a screening test with a sensitivity of >80% existed, the majority (probably approximately 75%) of cancers would be prevented by a single screening event at approximately 30 to 35 years of age. Unfortunately, no screening test exists as yet with a sensitivity in that range. Currently, the only possibility of improving the sensitivity is by a combination of tests.4,5,10,11 Increased cost, however, immediately becomes a prohibition. As an example, a model can be presented in which women are screened by both cytologic examination and direct AAT. A positive outcome would be a positive cytologic test or a positive direct AAT. On the basis of our own data, the sensitivity would be 90%, the specificity would be 47.9%, the positive predictive value would be 13.4%, and the negative predictive value would be 98.2%. The attractive aspects of this combination of two tests is the extremely high sensitivity of 90%, but there is a high degree of overdiagnosis, as reflected in the low specificity (47.9%) and a very low positive predictive value (13.4%). Therefore, it seems as if a combination of tests holds promise for use in developing countries, but a prerequisite will be tests with acceptable specificity and positive predictive values. Other factors to be taken into account are safety, feasibility, and cost-effectiveness. Another disturbing factor in a developing country is compliance. In our study, 876 women (80.2% of 1093 women) needed colposcopy, based on our liberal policy of referral, as described earlier. Ultimately, only 491 women (including 5 women who appeared at the colposcopy clinic without having returned to the screening clinic for their results) returned to the colposcopy clinic. Therefore, only 56.1% of the women who were eligible for colposcopy eventually returned. Similar results have been reported by Ghosh et al.11 On the basis of this experience, three important prerequisites for screening in a developing country have been identified: (1) as few screening events per lifetime as possible (the ideal would be only one); (2) a screening method that provides an immediate result, thereby eliminating the need to con-
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vey the test results to the patient at a later date; and (3) treatment that is applied immediately without having to refer the patient to another facility (particularly on another day). In Table II, an interesting aspect of the different screening tests is revealed. Positive cytologic examination was associated with more histologically proven high-grade lesions, although the other tests identified disease over the entire spectrum, maybe with a slight emphasis on lowgrade disease. This characteristic of cytologic examination, also confirmed by McCrory et al,8 makes it very useful in the screening of women who were ≥30 years old in whom more high-grade lesions are expected. In addition, Table II also shows the results of the punch biopsy specimens in cases in which either the direct AAT or speculoscopy was negative. In most cases, low-grade disease (atypia and LSIL) was diagnosed, but 17 patients (4%) had a histologic diagnosis of high-grade disease. We are not sure why these lesions did not stain white on acetic acid application. Because the biopsy specimens were taken from the external os, these lesions were not hidden within the endocervical canal. In 10% of the histologically documented cases with CIN II or more, all four screening tests were negative (9/90 cases). In a previous study from our unit, we used the same three screening tests; 23% of the patients with negative screening tests had positive histologic examination results (in this case ≥CIN-I).12 Taking into account these results, we conclude that, in a small proportion of patients, CIN lesions do occur that do not reflect on the direct AAT, cytologic examination, or cervicography. The reason for this phenomenon is not clear. Speculoscopy supposedly yields a higher specificity compared with direct AAT,13 a claim that is supported by a previous preliminary study of ours.14 However, in the current study no difference between these two methods of screening was found. One of the distressing aspects of this study was the high proportion of patients with a positive direct AAT and/or speculoscopy result (53.3% and 57.2%, respectively). Although our nurses were specially trained for this study (and retrained halfway through), the training was of short duration. More intense training could have resulted in a more realistic result, an important aspect when any of these tests are considered for mass screening. We did not perform testing for immunodeficiency virus infection in this study. This should, however, be taken into account in any screening program in a developing country. Not only can a higher prevalence of preinvasive neoplasia be expected, but also a remarkably high recurrence rate can be expected after treatment.15 In conclusion, none of the four tests that were evaluated in this study is well suited for cervical screening in a developing country. Cytologic examination has the advantage of being more sensitive for high-grade precursors
at a slightly more advanced age (>30 years), but its overall sensitivity is too low, and the logistics around cytologic screening are too complex. Cervicography has the advantage of an experienced evaluator evaluating the slides, but it suffers from a low specificity and is expensive and technically too demanding. The direct AAT and speculoscopy are comparable with the advantages of being inexpensive and simple, and they provide an immediate result with a high sensitivity. However, in both instances the specificity is too low for it to be a viable option. A combination of tests holds promise for being effective where the number of screening events have to be reduced, but cost and a low specificity remain problems. Other technologies to be investigated include the new technologies in cytologic examination and HPV DNA testing. Therefore, screening in a developing country remains problematic, with no clearly acceptable solutions. In view of the high incidence of cervical cancer in these countries, the search for an effective method of screening should receive high priority. We thank L. Berry, M. Khoalane, I. Niemand, E. Beyer, and G. Joubert for their valuable input.
REFERENCES
1. World Health Organization. Control of cancer of the cervix uteri. Bull World Health Organ 1986;64:607-18. 2. Sitas F, Blaauw D, Terblance M, Madhoo J, Carrava H. Incidence of histologically diagnosed cancer in South Africa, 1992. Johannesburg (South Africa): National Cancer Registry of South Africa, South African Institute of Medical Research; 1997. 3. Cronjé HS, Trümpelman MD, Divall PDJ, Scott LL, Middlecote BD, De Wet JI. Cervical cytological services in the Orange Free State: demographic characteristics. S Afr Med J 1989;76:615-8. 4. Wertlake PT, Francus K, Newkirk GR, Parham GP. Effectiveness of the Papanicolaou smear and speculoscopy as compared with the Papanicolaou smear alone: a community-based clinical trial. Obstet Gynecol 1997;90:421-7. 5. Olatunbosun OA, Okonofua FE, Ayangade SO. Screening for cervical neoplasia in an African population: simultaneous use of cytology and colposcopy. Int J Gynecol Obstet 1991;36:39-42. 6. Holowaty P, Miller AB, Rohan T, To T. Natural history of dysplasia of the uterine cervix. J Nat Can Inst 1999;91 252-8. 7. Fahey MT, Irwig L, Macaskill P. Meta-analysis of Pap test accuracy. Am J Epidemiol 1995;141:680-9. 8. McCrory DC, Matchar DB, Bastian L, Datta S, Hasselblad V, Hickey J, et al. Evaluation of cervical cytology: evidence report/technology assessment no. 5. Rockville (MD): Agency for Health Care Policy and Research; 1999. (Prepared by Duke University under contract no. 290-97-0014). AHCPR Publication No. 99-E010. 9. Nanda K, McCrory DC, Meyers ER, Bastian LA, Hasselblad V, Hickey JD, et al. Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review. Ann Intern Med 2000;132:810-9. 10. Lawson HW, Lee NC, Thames SF, Henson R, Miller DS. Cervical cancer screening among low-income women: results of a national screening program, 1991-1995. Obstet Gynecol 1998; 92:745-52. 11. Ghosh K, Segura A, Crispen C, Montz FJ. Use of the “see and treat” technique for the management of high-risk abnormal Papsmears in a third world country. Int J Gynecol Cancer 1997; 7:144-50.
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12. Cronjé HS, Cooreman BF, Beyer E, Bam RH, Middlecote BD, Divall PDJ. Screening for cervical neoplasia in a developing country utilizing cytology, cervicography and the acetic acid test. Int J Gynecol Obstet 2001;72:151-7. 13. Lonky NM, Edwards G. Chemiluminescent light improves observer ability to visualize aceto-white epithelium. Am J Gynecol Health 1992;6:11-5.
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14. Cronjé HS, Van Rensburg E, Cooreman BF, Niemand I, Beyer E. Speculoscopy vs the acetic acid test for cervical neoplasia. Int J Gynecol Obstet 2000;69:249-53. 15. Ellerbrock TV, Chiasson MA, Bush TJ, Sun X-W, Sawo D, Brudney K, et al. Incidence of cervical squamous intraepithelial lesions in HIV-infected women. JAMA 2000;283: 1031-7.
Key words: Screening, cervix, cytologic examination, cervicography, direct acetic acid test, speculoscopy
Cancer of the cervix is the most common malignancy in women in developing countries.1 At our institution, one in four patients with cancer (including children and men) is a woman with cancer of the cervix. Furthermore, the lifetime risk for a woman in South Africa for the development of this type of cancer is 1:26.2 This high prevalence is attributed mainly to a lack of screening, particularly in women of low income.3 From the Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Arkansas,b and the Departments of Obstetrics and Gynecologya and Anatomical Pathology and Cytology,c University of the Free State. Supported by the Medical Research Council (Bellville, South Africa) and by the Trylon Corporation (Torrance, Calif). Received for publication February 12, 2002; revised August 29, 2002; accepted September 27, 2002. Reprint requests: H. S. Cronjé, MD, Department of Obstetrics and Gynecology (G71), PO Box 339, Bloemfontein 9300, South Africa. E-mail: [email protected] © 2003, Mosby, Inc. All rights reserved. 0002-9378/2003 $30.00 + 0 doi:10.1067/mob.2003.153
Notwithstanding an enormous amount of research on screening for cervical neoplasia in developing countries, little progress has been made.1 In Africa, no country has managed to conduct sustainable large population-based screening programs. Chile is the only country in South America with a successful mass screening program, and only a few countries in Asia have been able to make significant progress with cervical screening. Even in a highly developed country such as the United States, an unexpectedly large number of infiltrating cervical cancers are diagnosed each year.1 The generally accepted cytologic smear of the cervix (Papanicolaou test) has certain disadvantages. It has a low sensitivity (often <50%4-6); expertise is needed to take and evaluate the specimens; and it is fairly expensive and does not provide an immediate result, so that women must return at a later date for the report. In developing countries, many women are lost in this process.3 In a developing country, the ideal screening test should be inexpensive; have a high sensitivity, specificity, and 395
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Table I. Characteristics of screening tests Screening test
Characteristic Threshold for positive screening result Threshold for positive histologic results Sensitivity (%) Specificity (%) Positive predictive value Negative predictive value
Cytologic examination
Cervicography
Direct AAT
Speculoscopy
≥LSIL ≥CIN II 53.3 94.6 47.1 95.7
≥Positive grade 1* ≥CIN II 48.9 87.5 26.0 95.0
White lesion or cancer ≥CIN II 78.9 48.9 12.2 96.3
White lesion or cancer ≥CIN II 76.7 44.6 11.0 95.5
*Condyloma and CIN I.
positive predictive value; and be relatively easy to evaluate and should provide an immediate result. Furthermore, it should also be acceptable to both the female clients and health care workers. In view of these prerequisites, we compared the cytologic test and cervicography, the direct acetic acid test (AAT) and the magnified AAT (speculoscopy). Our specific aim was to discover new possibilities for screening women in a developing country. Material and methods This study was approved by the Ethics Committee of the Faculty of Health Sciences, University of the Free State, South Africa, and was performed in accordance with the ethical standards set by the Declaration of Helsinki (1975, revised 1983). It was conducted in a large primary health care clinic at Pelonomi Hospital, one of our teaching institutions. Women who attended this clinic for any kind of ailment or disease were offered screening by means of a Papanicolaou test. When the woman accepted the offer, the study was explained to her by one of our study nurses (both professional nurses). If she refused the offer after the study had been explained, only a Papanicolaou test was taken, and she was excluded from further participation in the study. Inclusion criteria included women who were ≥30 years (although for ethical reasons we did not exclude younger women who spontaneously requested a Papanicolaou test) with an intact uterus. Exclusion criteria included previous cervical screening, pregnancy, heavy vaginal bleeding, and severe vaginitis or cervicitis. In total, 1286 women were included over an 18-month period. After giving informed consent, each woman was subjected to four screening tests that were performed by a professional nurse, in the following order: cytologic examination, cervicography, direct AAT, and speculoscopy. The nurse was a professional nurse who had been trained specially in the techniques of the different screening tests. After the last of these four tests, a punch biopsy (for histologic purposes) was taken from any acetowhite lesion on the cervix, if identified during the AAT or speculoscopy. In the absence of a visible acetowhite lesion, the biopsy specimen was taken from the external os, at either
the 12 o’clock or the 6 o’clock position, whichever was the most convenient. In addition, a biopsy specimen was taken from any lesion that was suggestive of cancer. The cytologic smear was taken with a Cervex-brush (Medscamp Med AD, Malmö, Sweden), which samples both the ectocervical and endocervical components, and was fixated on a glass slide with Cytological Fixative (Fencott, Sangene Products, Cape Town, South Africa). The slides were stained according to the Papanicolaou method and examined in the Department of Cytology, Faculty of Health Sciences, University of the Free State. Cervicography was performed with a Cerviscope (National Testing Laboratories Worldwide, St Louis, Mo). The slides were developed locally and evaluated by two of the authors who are United States–certified evaluators of cervicography (H. S. C. and B. F. C.) without knowledge of the results of any of the other tests. A cotton wool swab was soaked in a 5% acetic acid solution and gently pressed against the cervix for 30 seconds. The swab was removed, and the procedure was repeated with a second soaked swab. Thereafter, the first cervicography photograph was taken; after a third application of 5% acetic acid, the second photograph was taken. One of the study nurses then performed the direct AAT, which comprised a careful naked eye examination of the cervix for the presence of an acetowhite lesion or signs of infiltrating cancer. Speculoscopy was done immediately after the direct AAT but was always performed by the second nurse without knowledge of the direct AAT diagnosis made by the first nurse. A Speculite (Trylon Corporation, Torrance, Calif) was applied to the inside of the upper blade of the Cusco speculum after having been bent sharply, which resulted in the formation of a chemiluminescent light near the cervix. With the room darkened, the nurse examined the cervix with the aid of surgical loupes (magnification, 4) for the presence of an acetowhite lesion or signs of infiltrating cancer (Gynoscope; Perisphere Industries Inc, Torrance, Calif). After the fourth screening test, an Eppendorfer cervical biopsy forceps (BEI Medical Systems Inc, Gembloux, Belgium) was used to obtain a cervical punch biopsy specimen, as described earlier. The specimen was preserved
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Table II. Histologic results for patients with positive screening test results and the results of the random punch biopsy specimens Histologic results (n) Screening test Cytologic examination (n = 89) Cervicography (n = 235) Direct AAT (n = 583) Speculoscopy (n = 624) Random biopsy (n = 413)*
Negative
Atypia
CIN I
CIN II
Infiltrating cancer
2 (2.2%) 20 (8.5%) 104 (17.8%) 121 (19.4%) 56 (13.6%)
19 (21.3%) 84 (35.8%) 239 (41.0%) 267 (42.8%) 237 (57.4%)
23 (25.9%) 81 (34.5%) 169 (29.0%) 167 (26.8%) 103 (24.9%)
37 (41.6%) 41 (17.4%) 62 (10.6%) 60 (9.6%) 17 (4.1%)
8 (9.0%) 9 (3.8%) 9 (1.5%) 9 (1.4%) 0 (0%)
*These biopsy specimens were taken when the direct AAT and/or speculoscopy results were negative.
in 10% formal-saline solution and examined in the Department of Anatomical Pathology by one of the authors (A. deB.). If a patient had >1 histologic diagnosis (eg, a punch biopsy and an excisional biopsy), the one with the most severe degree of pathologic features was used in the analysis. Both the Papanicolaou tests and the biopsy specimens were evaluated without the knowledge of the results of the other tests. Patients with the following results were referred for colposcopy: (1) atypia of squamous cells of undetermined significance (ASCUS) or more severe pathologic features on cytologic examination, (2) all positive cervicography categories, (3) acetowhite lesions or possible cancer on the direct AAT or speculoscopy, and (4) condyloma, cervical intraepithelial lesion (CIN), or infiltrating cancer on histologic examination (punch biopsy). Two experienced colposcopists (H. S. C. and B. F. C.) performed the colposcopies. Biopsy-proved CIN lesions were treated by large loop excision of the transformation zone with the use of a Finesse II (Utah Medical Products, Midvale, Utah) electrosurgical apparatus. Infiltrating lesions were treated according to the standard protocol of the department. Descriptive statistics and 2--2 tables were generated with the EpiInfo 6 (version 6.02) statistical program (Centers for Disease Control and Prevention, Atlanta, Ga). Results In 193 of the 1286 women (15%) who were included in the study, at least one test result was defective or unavailable, which left the results of 1093 women (85%) that were eligible for analysis. The mean age of these women was 38.6 years (median, 38.0 years), with a range of 21 to 65 years. Only 12% were <30 years of age. The mean parity was 2.5 (median, 2.0), with a range of 0 to 11. Contraception was used by 30.8% of the patients, with an additional 14.3% having undergone sterilization. Smoking was reported by 17.2% of the women, and the use of snuff (inhaling of tobacco powder) was reported by 24.4% women. Two thirds of the women (728/1093 women) returned for their results. Of these, 604 women (83%) were re-
ferred for further evaluation, of whom 468 women (78%) returned for colposcopy and possible treatment. The 468 women who eventually returned for colposcopy represented 56% of the 876 women who originally met the established criteria for colposcopic evaluation. The cytologic examination results were as follows (n = 1093 women): negative, 960 women (87.8%); ASCUS or AGUS, 31 women (2.8%); low-grade squamous intraepithelial lesion (LSIL), 39 women (3.6%); HSIL, 52 women (4.7%), and infiltrating cancer, 11 women (1.0%). In Table I, a summary is given of the cytologic examination’s sensitivity and other characteristics. Cervicography’s results were as follows (n = 1093 women): negative, 748 women (68.4%); atypical, 110 women (10.1%); P0, 36 women (3.3%); positive grade 1, 156 women (14.3%); P2, 34 women (3.1%); and infiltrating cancer (P3), 9 women (0.8%). Positive grade 0 means probably negative, but colposcopy and biopsy are needed for the exclusion of cancer; positive grades 1 and 2 are LSIL and HSIL, respectively; and positive grade 3 indicates infiltrating cancer. The different characteristics of cervicography are also shown in Table I. The direct AAT was negative in 510 cases (46.7%); an acetowhite lesion was noted in 577 cases (52.8%), and possible cancer was noted in 6 cases (0.5%, n = 1093 women). Speculoscopy’s results were negative in 468 women (42.8%); an acetowhite lesion was noted in 617 women (56.5%), and possible cancer was noted in 8 women (0.7%, n = 1093 women). The characteristics are summarized in Table I. Histologic results of the cervical punch biopsy specimens (which were obtained at the time of screening) and the excisional biopsy specimens (which were obtained during colposcopic evaluation) were as follows (n = 1093 women): negative, 183 cases (16.7%); atypia, 3 cases (0.3%); koilocytosis, 346 cases (31.7%); condyloma, 179 cases (16.4%); CIN I, 292 cases (26.7%); CIN II, 50 cases (4.6%); CIN III, 31 cases (2.8%); and infiltrating cancer, in 9 cases (0.8%). If a patient had >1 histologic result (eg, a punch biopsy and an excisional biopsy), the most severe result was documented here. In Table II, the histologic results of patients with positive screening tests are shown.
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Table II includes the results of the punch biopsy specimens that were taken from patients who had no visible acetowhite lesion at the initial screening. Comment In this study, the sample was taken from a population of clinic attenders. Realizing that this population was not similar to the general population, we still considered it acceptable because of the availability of women to be screened and an expected higher prevalence of cervical neoplasia. Whether this selection influenced the sensitivity of the different tests is uncertain. The mean age of the patients in this study was higher when compared with most other studies of this kind: 38.6 years versus 34.1 years and 28.0 years in the reports of Wertlake et al4 (United States) and Olatunbosun et al5 (Africa). We used 30 years as the minimum age for inclusion because, by that age, most of the minor lesions (ASCUS and even LSIL) would have regressed.6 After 30 years, we also expected a lower prevalence and a lesser degree of cervicitis. However, younger women who turned up at the screening clinic requesting cervical screening were not refused. This approach resulted in the rather older mean age, where a high prevalence of high-grade disease can be expected. Indeed, in our population 8.2% of patients had histologically proven HSIL and cancer, an extremely high prevalence. The sensitivity of cytologic examination is a subject of debate. In an excellent review, Fahey et al7 reported a sensitivity of 58% and a specificity of 69%. The authors pointed out that unless histologic condition (the gold standard or reference test) is determined on all screening negatives in addition to the screening positives, the sensitivity will be unrealistically high.7 This statement was confirmed in more recent reviews of the sensitivity of cytologic examination.8,9 In the comprehensive review by McCrory et al,8 the sensitivity of cytologic examination in the least-biased studies was found to be 51%, with a 95% CI of 37%-66%. However, it was emphasized that the new techniques in cytologic examination (thin layer cytologic examination and computerized rescreening) were associated with an increased sensitivity. Nanda et al9 expanded the study by McCrory et al and found that for the nine studies that reported an LSIL/CIN-I threshold in a lowrisk population, sensitivity ranged from 30% to 87% (mean, 47%; median, 42%; <60% in eight of these studies). As expected, for the HSIL/CIN-II-III threshold, the sensitivity was higher and ranged from 44% to 99% (mean, 71%; median 68.5%). In our study it was 53%, with the use of an LSIL threshold for cytologic examination and CIN II for histologic examination. In a developing country, the number of screening events per woman per lifetime has to be restricted because of cost constraints, compliance, and coverage. The World Health Organization proposed a policy of at least
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one cytologic test at the age of 35 to 40 years.1 In South Africa, the government approved a policy of three tests per lifetime, starting at age 30 years, with 10-year intervals. When the number of screening events per lifetime is reduced, the sensitivity of the screening test has to be increased. Cytologic examination, with its relatively low sensitivity, is certainly not a viable option within such a scenario. The new technologies in cytologic examination (thin-layer cytologic examination and computerized rescreening) may be a viable alternative that must be considered. The developmental phase of cervical neoplasia covers ≥2 decades, starting with atypia and LSIL and terminating in cancer.4 It seems unlikely for a woman to have the first preinvasive changes on the cervix, which can lead ultimately to invasive cancer after 30 or 35 years of age. Therefore, if a screening test with a sensitivity of >80% existed, the majority (probably approximately 75%) of cancers would be prevented by a single screening event at approximately 30 to 35 years of age. Unfortunately, no screening test exists as yet with a sensitivity in that range. Currently, the only possibility of improving the sensitivity is by a combination of tests.4,5,10,11 Increased cost, however, immediately becomes a prohibition. As an example, a model can be presented in which women are screened by both cytologic examination and direct AAT. A positive outcome would be a positive cytologic test or a positive direct AAT. On the basis of our own data, the sensitivity would be 90%, the specificity would be 47.9%, the positive predictive value would be 13.4%, and the negative predictive value would be 98.2%. The attractive aspects of this combination of two tests is the extremely high sensitivity of 90%, but there is a high degree of overdiagnosis, as reflected in the low specificity (47.9%) and a very low positive predictive value (13.4%). Therefore, it seems as if a combination of tests holds promise for use in developing countries, but a prerequisite will be tests with acceptable specificity and positive predictive values. Other factors to be taken into account are safety, feasibility, and cost-effectiveness. Another disturbing factor in a developing country is compliance. In our study, 876 women (80.2% of 1093 women) needed colposcopy, based on our liberal policy of referral, as described earlier. Ultimately, only 491 women (including 5 women who appeared at the colposcopy clinic without having returned to the screening clinic for their results) returned to the colposcopy clinic. Therefore, only 56.1% of the women who were eligible for colposcopy eventually returned. Similar results have been reported by Ghosh et al.11 On the basis of this experience, three important prerequisites for screening in a developing country have been identified: (1) as few screening events per lifetime as possible (the ideal would be only one); (2) a screening method that provides an immediate result, thereby eliminating the need to con-
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vey the test results to the patient at a later date; and (3) treatment that is applied immediately without having to refer the patient to another facility (particularly on another day). In Table II, an interesting aspect of the different screening tests is revealed. Positive cytologic examination was associated with more histologically proven high-grade lesions, although the other tests identified disease over the entire spectrum, maybe with a slight emphasis on lowgrade disease. This characteristic of cytologic examination, also confirmed by McCrory et al,8 makes it very useful in the screening of women who were ≥30 years old in whom more high-grade lesions are expected. In addition, Table II also shows the results of the punch biopsy specimens in cases in which either the direct AAT or speculoscopy was negative. In most cases, low-grade disease (atypia and LSIL) was diagnosed, but 17 patients (4%) had a histologic diagnosis of high-grade disease. We are not sure why these lesions did not stain white on acetic acid application. Because the biopsy specimens were taken from the external os, these lesions were not hidden within the endocervical canal. In 10% of the histologically documented cases with CIN II or more, all four screening tests were negative (9/90 cases). In a previous study from our unit, we used the same three screening tests; 23% of the patients with negative screening tests had positive histologic examination results (in this case ≥CIN-I).12 Taking into account these results, we conclude that, in a small proportion of patients, CIN lesions do occur that do not reflect on the direct AAT, cytologic examination, or cervicography. The reason for this phenomenon is not clear. Speculoscopy supposedly yields a higher specificity compared with direct AAT,13 a claim that is supported by a previous preliminary study of ours.14 However, in the current study no difference between these two methods of screening was found. One of the distressing aspects of this study was the high proportion of patients with a positive direct AAT and/or speculoscopy result (53.3% and 57.2%, respectively). Although our nurses were specially trained for this study (and retrained halfway through), the training was of short duration. More intense training could have resulted in a more realistic result, an important aspect when any of these tests are considered for mass screening. We did not perform testing for immunodeficiency virus infection in this study. This should, however, be taken into account in any screening program in a developing country. Not only can a higher prevalence of preinvasive neoplasia be expected, but also a remarkably high recurrence rate can be expected after treatment.15 In conclusion, none of the four tests that were evaluated in this study is well suited for cervical screening in a developing country. Cytologic examination has the advantage of being more sensitive for high-grade precursors
at a slightly more advanced age (>30 years), but its overall sensitivity is too low, and the logistics around cytologic screening are too complex. Cervicography has the advantage of an experienced evaluator evaluating the slides, but it suffers from a low specificity and is expensive and technically too demanding. The direct AAT and speculoscopy are comparable with the advantages of being inexpensive and simple, and they provide an immediate result with a high sensitivity. However, in both instances the specificity is too low for it to be a viable option. A combination of tests holds promise for being effective where the number of screening events have to be reduced, but cost and a low specificity remain problems. Other technologies to be investigated include the new technologies in cytologic examination and HPV DNA testing. Therefore, screening in a developing country remains problematic, with no clearly acceptable solutions. In view of the high incidence of cervical cancer in these countries, the search for an effective method of screening should receive high priority. We thank L. Berry, M. Khoalane, I. Niemand, E. Beyer, and G. Joubert for their valuable input.
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1. World Health Organization. Control of cancer of the cervix uteri. Bull World Health Organ 1986;64:607-18. 2. Sitas F, Blaauw D, Terblance M, Madhoo J, Carrava H. Incidence of histologically diagnosed cancer in South Africa, 1992. Johannesburg (South Africa): National Cancer Registry of South Africa, South African Institute of Medical Research; 1997. 3. Cronjé HS, Trümpelman MD, Divall PDJ, Scott LL, Middlecote BD, De Wet JI. Cervical cytological services in the Orange Free State: demographic characteristics. S Afr Med J 1989;76:615-8. 4. Wertlake PT, Francus K, Newkirk GR, Parham GP. Effectiveness of the Papanicolaou smear and speculoscopy as compared with the Papanicolaou smear alone: a community-based clinical trial. Obstet Gynecol 1997;90:421-7. 5. Olatunbosun OA, Okonofua FE, Ayangade SO. Screening for cervical neoplasia in an African population: simultaneous use of cytology and colposcopy. Int J Gynecol Obstet 1991;36:39-42. 6. Holowaty P, Miller AB, Rohan T, To T. Natural history of dysplasia of the uterine cervix. J Nat Can Inst 1999;91 252-8. 7. Fahey MT, Irwig L, Macaskill P. Meta-analysis of Pap test accuracy. Am J Epidemiol 1995;141:680-9. 8. McCrory DC, Matchar DB, Bastian L, Datta S, Hasselblad V, Hickey J, et al. Evaluation of cervical cytology: evidence report/technology assessment no. 5. Rockville (MD): Agency for Health Care Policy and Research; 1999. (Prepared by Duke University under contract no. 290-97-0014). AHCPR Publication No. 99-E010. 9. Nanda K, McCrory DC, Meyers ER, Bastian LA, Hasselblad V, Hickey JD, et al. Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review. Ann Intern Med 2000;132:810-9. 10. Lawson HW, Lee NC, Thames SF, Henson R, Miller DS. Cervical cancer screening among low-income women: results of a national screening program, 1991-1995. Obstet Gynecol 1998; 92:745-52. 11. Ghosh K, Segura A, Crispen C, Montz FJ. Use of the “see and treat” technique for the management of high-risk abnormal Papsmears in a third world country. Int J Gynecol Cancer 1997; 7:144-50.
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14. Cronjé HS, Van Rensburg E, Cooreman BF, Niemand I, Beyer E. Speculoscopy vs the acetic acid test for cervical neoplasia. Int J Gynecol Obstet 2000;69:249-53. 15. Ellerbrock TV, Chiasson MA, Bush TJ, Sun X-W, Sawo D, Brudney K, et al. Incidence of cervical squamous intraepithelial lesions in HIV-infected women. JAMA 2000;283: 1031-7.