- Email: [email protected]
Hyperplastic polyps and risk of adenomas
1144
CORRESPONDENCE
ies bind selectively to central, peripheral and autonomic nervous system cells. Lab Invest 1991;65(4):0ctober. 8. Lennon VA. Letter to the Editor, Anti-Purkinje cell cytoplasmic and anti-neuronal nuclear antibodies aid diagnosis of paraneoplastic autoimmune neurological disorders. J Neurol Neurosurg Psychiatr 1989;52:1438-1439. 9. Altermatt HJ, Williams CL, Lennon VA. Paraneoplastic cerebellar autoantibodies associated with gynecologic cancer bind to myenteric plexus neurons (letter). Ann Neurol 1991;29:687688. 10. Luque FA, Furneaux HM, Ferziger R, et al. Anti-Ri: an antibody associated with paraneoplastic opsoclonus and breast cancer. Ann Neurol1991:29:241-251.
GASTROENTEROLOGY
predictors of risk for proximal adenomas and that simply reporting the proportion of patients with distal hyperplastic polyps who have proximal adenomas is not helpful clinically; the critical question is whether the proportion is greater among persons with distal hyperplastic polyps than the proportion of those without such polyps. In light of the data from screening colonoscopic examinations, which show a relatively high prevalence of proximal adenomas in patients with no distal polyps, we feel that the data in the Blue study cannot support the conclusion that distal hyperplastic polyps are useful markers for proximal colonic adenomas without knowing the prevalence of proximal adenomas in their patient population without distal polyps. SUZANNA I. PARK, M.D. Division of Digestive Diseases University of Cincinnati Medical Center Cincinnati, Ohio
Hyperplastic Polyps and Risk of Adenomas Dear Sir: We read with interest the recent study by Blue et al. (1) on hyperplastic rectal polyps as markers for proximal colonic adenomas. This prospective study evaluated 3133 asymptomatic individuals who were referred for screening flexible sigmoidoscopic examination. Of these patients, 185 were found to have polyps and were further evaluated with colonoscopy and polypectomy. Ninetynine subjects had at least one rectosigmoid adenoma, and 69 had only hyperplastic polyps in the rectosigmoid area. Proximal adenomas were found in 29% of patients with adenomatous rectosigmoid polyps compared with 28% in patients with hyperplastic rectosigmoid polyps. Based on the similarity in percentages, the authors concluded that patients with rectosigmoid hyperplastic polyps have the same risk for additional proximal adenomas as patients with rectosigmoid adenomatous polyps. Although Fisher’s Exact Test was reportedly performed when appropriate, the specific statistical test used to compare the prevalence of proximal adenomas in patients with distal hyperplastic polyps vs. those with distal adenomatous polyps was not given. In addition, the level of statistical significance observed and the confidence intervals for the main results of the study were not reported, so it is difficult to assess the clinical and statistical significance of this paper. Most important, however, this study did not determine the prevalence of proximal colonic adenomas in a comparison control population of asymptomatic individuals without rectosigmoid polyps. Without this information, statistical measures of association cannot be calculated to objectively assess the risk of proximal adenomas in patients with distal hyperplastic polyps. Evidence is accumulating that there is a relatively high prevalence of colonic adenomas in asymptomatic patients over the age of 50. Three recent prospective studies of screening colonoscopy in asymptomatic individuals have been performed. Johnson et al. (2) found a 24% prevalence of colonic adenomas (46% of the neoplasms were proximal to the splenic flexure); Lieberman et al. (3) found a 44% prevalence of colonic adenomas (22% were proximal to the sigmoid colon): and Rex et al. (4) found a 25% prevalence of colonic adenomas (17% were proximal to the sigmoid colon). Hence, the proximal adenomas observed in patients with distal hyperplastic polyps in the Blue study may have been present simply because of an age-related risk for colonic neoplasia and not because of hyperplastic polyps. In the only other prospective study (5) evaluating the risk of proximal colonic adenomas in symptomatic patients with hyperplastic polyps, the prevalence of proximal adenomas in patients with distal rectosigmoid hyperplastic polyps was found to be 31.9%, similar to that found in the Blue study. However, Provenzale et al. compared their data with the prevalence of proximal adenomas in their patient population without distal rectosigmoid polyps and found no statistically significant difference between the two groups. They concluded that distal hyperplastic polyps are not strong
Vol. 101, No. 4
KENNETHL. RADACK, M.D. Associate Professor of Medicine Department of Internal Medicine University of Cincinnati Medical Center Cincinnati, Ohio ROBERT E. WEESNER, M.D. Digestive Disease Section Department of VeteransAffairs Medical Center Cincinnati, Ohio 1. Blue MG, Sivak MV, Achkar E, Matzen R, Stahl RR. Hyperplastic
2.
3.
4.
5.
polyps seen at sigmoidoscopy are markers for additional adenomas seen at colonoscopy. Gastroenterology 1991;100:564566. Johnson DA, Gurney MS, Volpe RJ, Jones DM, VanNess MM, et al. A prospective study of the prevalence of colonic neoplasms in asymptomatic patients with an age-related risk. Am J Gastroenter01 1990;85:969-974, Lieberman D, Denberg T, Smith F. Screening for colon malignancy with colonoscopy in asymptomatic subjects. Gastrointest Endosc 1989;35:174. Rex D, Lehman G, Hawes R, Ulbright T, Smith J. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroeneterology 1991;100:64-67. Provenzale D, Garrett JW, Condon SE, Sandler RS. Risk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann Intern Med 1990;113:760-763.
Dear Sir: The experience reported by Blue et al. (1) regarding the prevalence of proximal adenomas in patients with distal hyperplastic polyps underscores the variability found in previous studies. The evidence seems to be fairly evenly divided, and a critical question is whether biopsy of small polyps seen at the initial flexible sigmoidoscopy should always be performed. In an effort to define this problem in our patient population, we performed flexible sigmoidoscopy in 256 veterans. One hundred twenty-three of them had distal polyps. They underwent colonoscopy and were grouped into an asymptomatic subset (therefore undergoing colorectal screening) and a symptomatic subset (hematochezia and/or other symptoms). The first group consisted of 30 patients (mean age, 60 years) and the second of 93 patients (mean age, 65 years). Even though a positive association was found between the presence of distal neoplastic lesions and proximal neoplastic lesions (overall prevalence, 20%) no association was found between distal hyperplastic polyps and proximal neoplastic polyps were <5 mm in lesions (0%; P < 0.02). All hyperplastic size. In a similar fashion, Provenzale et al. found that proximal adenomas were no more frequent in patients with distal hyperplastic polyps (2). Other authors have produced similar findings (3,4). It
October
CORRESPONDENCE
1991
may be that the basic pathogenetic mechanism of hyperplastic polyps is totally different from that of the premalignant ones and that they are thus separate processes in the same colon. Our study also produced evidence of the fairly high rate of proximal adenomas found in patients above the age of 60 years (11% in symptomatics vs. 10% in asymptomatics). Our current strategy is not to perform biopsy on polyps seen at an initial flexible sigmoidoscopy but to follow up with a colonoscopy. Other authors whose findings are similar to ours advise against pursuing the problem further by a full colonoscopy after distal hyperplastic polyps are found (2). Adenomas in subjects above the age of 60 years appear to be very common, and screening strategies may have to change in this age group. In other words, performing screening flexible sigmoidoscopy in asymptomatic subjects aged 50-60 years may be adequate. In those over 60, colonoscopy may be more appropriate. THOMAS P. SHORT, M.D.
Fellow, Division of Gastroentemlogy EAPEN THOMAS, M.D.
Chiej Division of Gastroeneterology lames H. Quillen College of Medicine East Tennessee State University lohnson City, Tennessee 3i’614-0002 Blue MG. Sivak MV, Achkar E, Matzen R, Stahl RR. Hyperplastic polyps seen at sigmoidoscopy are markers for additional adenomas seen at colonoscopy. Gastroenterology 1991;100:564566. Provenzale D, Garrett JW, Condon SE, Sandler RS. Risk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann Intern Med 1990;113:769-763. Rex DK, Lehman GA, Howes RH, Ulbright TM, Smith JJ. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroenterology 1991;lOO:
interval, 12.1-15.6). Although the confidence interval was wide, the best estimate of the population difference was 1.8%, the difference between the sample percentages. Additionally, the estimated elective risk was 1.04 (95% confidence interval, 0.79-1.36), suggesting a similar risk between patients with hyperplastic rectosigmoid polyps and those with adenomatous polyps. In other words, there was no association between polyp type and discovery of additional proximal adenomas. In addition, Drs. Park and Weesner are critical of the fact that we did not have a control population of subjects without rectosigmoid polyps. We agree that this information is important. However, our aim was to evaluate current recommendations of obtaining colonoscopy only when an adenoma was present in the rectum (1). By showing that patients with distal hyperplastic polyps have the same rate of proximal adenomas, we wanted to point out that the recommendation needed to be reconsidered. Other authors reported similar results (2,3). Other studies have shown that asymptomatic subjects with no polyps in the rectum have a discovery rate of proximal adenomas of 25%44% (4,5). Why is it acceptable to abstain from obtaining colonoscopy in subjects with no rectal polyps or subjects with distal hyperplastic polyps but not in patients with adenomatous polyps if the chance of discovering proximal adenomas is similar in all groups? The high prevalence of colonic adenomas in the Provenzale series is probably due to the fact that 46% of their patients were symptomatic (gastrointestinal bleeding or anemia] (6) and 28% had prior colonic polyps. The bottom line is that multiple studies have now shown that about a third of patients with hyperplastic polyps in the rectum will have adenomatous polyps proximally. This is an unacceptable rate of untreated neoplastic polyps. We believe colonoscopy is important for any group of subjects in whom one third will have significant polyps. EDGAR ACHKAR. M.D. MICHAEL V. SIVAK. M.D.
64-67.
Achkar E, Carey W. Small sigmoidoscopy in asymptomatic 109:880-883.
polyps found during patients. Ann Intern
1145
Cleveland Clinic Foundation 9500 EuclidAvenue Cleveland, Ohio 44 I 95
fiberoptic Med 1988;
1. American
Reply. Drs. Short and Thomas report their experience with a group of patients undergoing sigmoidoscopy. They found no neoplastic adenomas in any patients with hyperplastic polyps in the rectum. This result is at odds with most studies in both symptomatic and asymptomatic subjects of whom at least 25%30% have proximal adenomas. The difference may be due to the small number of asymptomatic subjects in their study. Their policy of obtaining a colonoscopy any time a rectal polyp is found is similar to ours. We agree that a different strategy may be advisable in the future based on age, number, or size of polyps, but there is no solid evidence at the present time to guide us in the choice of such a strategy. Drs. Park and Weesner request some clarification as to the statistical validity of our findings. Proximal adenomas were found in 29% of patients with rectal adenomatous polyps and in 28% of patients with rectal hyperplastic polyps. Using Fisher’s Exact Test, no difference was detected between the groups. The observed difference between the proportions was only 1.8% (95% confidence
Society for Gastrointestinal Endoscopy. Appropriate use of gastrointestinal endoscopy. Manchester, MA: American Society for Gastrointestinal Endoscopy, 1986. 2. Stoltenberg PH, Kirtley DW, Culp KS, LeSage GD, White JG. Are diminutive colorectal polyps (DCP) clinically significant? (abstr). Gastrointest Endosc 1988;34:172. AF, Lewis JH, Fleischer DE, et al. Hyperplastic colonic 3. Ansher polyps as a marker for adenomatous colonic polyps. Am J Gastroenterol84:113-117, 1989. 4. Rex DK, Lehman GA, Hawes RH, Ulbright TM, Smith JJ. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroenterology 1991;lOO: 64-67. 5. Lieberman
D, Denberg T, Smith F. Feasibility of colonoscopic screening of asymptomatic subjects (abstr). Gastrointest Endosc 1989;35:174. 6. Provenzale D, Garrett JW, Condon SE, Sandler RS. Kisk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann InternMed 1990;113:760-763.
CORRESPONDENCE
ies bind selectively to central, peripheral and autonomic nervous system cells. Lab Invest 1991;65(4):0ctober. 8. Lennon VA. Letter to the Editor, Anti-Purkinje cell cytoplasmic and anti-neuronal nuclear antibodies aid diagnosis of paraneoplastic autoimmune neurological disorders. J Neurol Neurosurg Psychiatr 1989;52:1438-1439. 9. Altermatt HJ, Williams CL, Lennon VA. Paraneoplastic cerebellar autoantibodies associated with gynecologic cancer bind to myenteric plexus neurons (letter). Ann Neurol 1991;29:687688. 10. Luque FA, Furneaux HM, Ferziger R, et al. Anti-Ri: an antibody associated with paraneoplastic opsoclonus and breast cancer. Ann Neurol1991:29:241-251.
GASTROENTEROLOGY
predictors of risk for proximal adenomas and that simply reporting the proportion of patients with distal hyperplastic polyps who have proximal adenomas is not helpful clinically; the critical question is whether the proportion is greater among persons with distal hyperplastic polyps than the proportion of those without such polyps. In light of the data from screening colonoscopic examinations, which show a relatively high prevalence of proximal adenomas in patients with no distal polyps, we feel that the data in the Blue study cannot support the conclusion that distal hyperplastic polyps are useful markers for proximal colonic adenomas without knowing the prevalence of proximal adenomas in their patient population without distal polyps. SUZANNA I. PARK, M.D. Division of Digestive Diseases University of Cincinnati Medical Center Cincinnati, Ohio
Hyperplastic Polyps and Risk of Adenomas Dear Sir: We read with interest the recent study by Blue et al. (1) on hyperplastic rectal polyps as markers for proximal colonic adenomas. This prospective study evaluated 3133 asymptomatic individuals who were referred for screening flexible sigmoidoscopic examination. Of these patients, 185 were found to have polyps and were further evaluated with colonoscopy and polypectomy. Ninetynine subjects had at least one rectosigmoid adenoma, and 69 had only hyperplastic polyps in the rectosigmoid area. Proximal adenomas were found in 29% of patients with adenomatous rectosigmoid polyps compared with 28% in patients with hyperplastic rectosigmoid polyps. Based on the similarity in percentages, the authors concluded that patients with rectosigmoid hyperplastic polyps have the same risk for additional proximal adenomas as patients with rectosigmoid adenomatous polyps. Although Fisher’s Exact Test was reportedly performed when appropriate, the specific statistical test used to compare the prevalence of proximal adenomas in patients with distal hyperplastic polyps vs. those with distal adenomatous polyps was not given. In addition, the level of statistical significance observed and the confidence intervals for the main results of the study were not reported, so it is difficult to assess the clinical and statistical significance of this paper. Most important, however, this study did not determine the prevalence of proximal colonic adenomas in a comparison control population of asymptomatic individuals without rectosigmoid polyps. Without this information, statistical measures of association cannot be calculated to objectively assess the risk of proximal adenomas in patients with distal hyperplastic polyps. Evidence is accumulating that there is a relatively high prevalence of colonic adenomas in asymptomatic patients over the age of 50. Three recent prospective studies of screening colonoscopy in asymptomatic individuals have been performed. Johnson et al. (2) found a 24% prevalence of colonic adenomas (46% of the neoplasms were proximal to the splenic flexure); Lieberman et al. (3) found a 44% prevalence of colonic adenomas (22% were proximal to the sigmoid colon): and Rex et al. (4) found a 25% prevalence of colonic adenomas (17% were proximal to the sigmoid colon). Hence, the proximal adenomas observed in patients with distal hyperplastic polyps in the Blue study may have been present simply because of an age-related risk for colonic neoplasia and not because of hyperplastic polyps. In the only other prospective study (5) evaluating the risk of proximal colonic adenomas in symptomatic patients with hyperplastic polyps, the prevalence of proximal adenomas in patients with distal rectosigmoid hyperplastic polyps was found to be 31.9%, similar to that found in the Blue study. However, Provenzale et al. compared their data with the prevalence of proximal adenomas in their patient population without distal rectosigmoid polyps and found no statistically significant difference between the two groups. They concluded that distal hyperplastic polyps are not strong
Vol. 101, No. 4
KENNETHL. RADACK, M.D. Associate Professor of Medicine Department of Internal Medicine University of Cincinnati Medical Center Cincinnati, Ohio ROBERT E. WEESNER, M.D. Digestive Disease Section Department of VeteransAffairs Medical Center Cincinnati, Ohio 1. Blue MG, Sivak MV, Achkar E, Matzen R, Stahl RR. Hyperplastic
2.
3.
4.
5.
polyps seen at sigmoidoscopy are markers for additional adenomas seen at colonoscopy. Gastroenterology 1991;100:564566. Johnson DA, Gurney MS, Volpe RJ, Jones DM, VanNess MM, et al. A prospective study of the prevalence of colonic neoplasms in asymptomatic patients with an age-related risk. Am J Gastroenter01 1990;85:969-974, Lieberman D, Denberg T, Smith F. Screening for colon malignancy with colonoscopy in asymptomatic subjects. Gastrointest Endosc 1989;35:174. Rex D, Lehman G, Hawes R, Ulbright T, Smith J. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroeneterology 1991;100:64-67. Provenzale D, Garrett JW, Condon SE, Sandler RS. Risk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann Intern Med 1990;113:760-763.
Dear Sir: The experience reported by Blue et al. (1) regarding the prevalence of proximal adenomas in patients with distal hyperplastic polyps underscores the variability found in previous studies. The evidence seems to be fairly evenly divided, and a critical question is whether biopsy of small polyps seen at the initial flexible sigmoidoscopy should always be performed. In an effort to define this problem in our patient population, we performed flexible sigmoidoscopy in 256 veterans. One hundred twenty-three of them had distal polyps. They underwent colonoscopy and were grouped into an asymptomatic subset (therefore undergoing colorectal screening) and a symptomatic subset (hematochezia and/or other symptoms). The first group consisted of 30 patients (mean age, 60 years) and the second of 93 patients (mean age, 65 years). Even though a positive association was found between the presence of distal neoplastic lesions and proximal neoplastic lesions (overall prevalence, 20%) no association was found between distal hyperplastic polyps and proximal neoplastic polyps were <5 mm in lesions (0%; P < 0.02). All hyperplastic size. In a similar fashion, Provenzale et al. found that proximal adenomas were no more frequent in patients with distal hyperplastic polyps (2). Other authors have produced similar findings (3,4). It
October
CORRESPONDENCE
1991
may be that the basic pathogenetic mechanism of hyperplastic polyps is totally different from that of the premalignant ones and that they are thus separate processes in the same colon. Our study also produced evidence of the fairly high rate of proximal adenomas found in patients above the age of 60 years (11% in symptomatics vs. 10% in asymptomatics). Our current strategy is not to perform biopsy on polyps seen at an initial flexible sigmoidoscopy but to follow up with a colonoscopy. Other authors whose findings are similar to ours advise against pursuing the problem further by a full colonoscopy after distal hyperplastic polyps are found (2). Adenomas in subjects above the age of 60 years appear to be very common, and screening strategies may have to change in this age group. In other words, performing screening flexible sigmoidoscopy in asymptomatic subjects aged 50-60 years may be adequate. In those over 60, colonoscopy may be more appropriate. THOMAS P. SHORT, M.D.
Fellow, Division of Gastroentemlogy EAPEN THOMAS, M.D.
Chiej Division of Gastroeneterology lames H. Quillen College of Medicine East Tennessee State University lohnson City, Tennessee 3i’614-0002 Blue MG. Sivak MV, Achkar E, Matzen R, Stahl RR. Hyperplastic polyps seen at sigmoidoscopy are markers for additional adenomas seen at colonoscopy. Gastroenterology 1991;100:564566. Provenzale D, Garrett JW, Condon SE, Sandler RS. Risk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann Intern Med 1990;113:769-763. Rex DK, Lehman GA, Howes RH, Ulbright TM, Smith JJ. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroenterology 1991;lOO:
interval, 12.1-15.6). Although the confidence interval was wide, the best estimate of the population difference was 1.8%, the difference between the sample percentages. Additionally, the estimated elective risk was 1.04 (95% confidence interval, 0.79-1.36), suggesting a similar risk between patients with hyperplastic rectosigmoid polyps and those with adenomatous polyps. In other words, there was no association between polyp type and discovery of additional proximal adenomas. In addition, Drs. Park and Weesner are critical of the fact that we did not have a control population of subjects without rectosigmoid polyps. We agree that this information is important. However, our aim was to evaluate current recommendations of obtaining colonoscopy only when an adenoma was present in the rectum (1). By showing that patients with distal hyperplastic polyps have the same rate of proximal adenomas, we wanted to point out that the recommendation needed to be reconsidered. Other authors reported similar results (2,3). Other studies have shown that asymptomatic subjects with no polyps in the rectum have a discovery rate of proximal adenomas of 25%44% (4,5). Why is it acceptable to abstain from obtaining colonoscopy in subjects with no rectal polyps or subjects with distal hyperplastic polyps but not in patients with adenomatous polyps if the chance of discovering proximal adenomas is similar in all groups? The high prevalence of colonic adenomas in the Provenzale series is probably due to the fact that 46% of their patients were symptomatic (gastrointestinal bleeding or anemia] (6) and 28% had prior colonic polyps. The bottom line is that multiple studies have now shown that about a third of patients with hyperplastic polyps in the rectum will have adenomatous polyps proximally. This is an unacceptable rate of untreated neoplastic polyps. We believe colonoscopy is important for any group of subjects in whom one third will have significant polyps. EDGAR ACHKAR. M.D. MICHAEL V. SIVAK. M.D.
64-67.
Achkar E, Carey W. Small sigmoidoscopy in asymptomatic 109:880-883.
polyps found during patients. Ann Intern
1145
Cleveland Clinic Foundation 9500 EuclidAvenue Cleveland, Ohio 44 I 95
fiberoptic Med 1988;
1. American
Reply. Drs. Short and Thomas report their experience with a group of patients undergoing sigmoidoscopy. They found no neoplastic adenomas in any patients with hyperplastic polyps in the rectum. This result is at odds with most studies in both symptomatic and asymptomatic subjects of whom at least 25%30% have proximal adenomas. The difference may be due to the small number of asymptomatic subjects in their study. Their policy of obtaining a colonoscopy any time a rectal polyp is found is similar to ours. We agree that a different strategy may be advisable in the future based on age, number, or size of polyps, but there is no solid evidence at the present time to guide us in the choice of such a strategy. Drs. Park and Weesner request some clarification as to the statistical validity of our findings. Proximal adenomas were found in 29% of patients with rectal adenomatous polyps and in 28% of patients with rectal hyperplastic polyps. Using Fisher’s Exact Test, no difference was detected between the groups. The observed difference between the proportions was only 1.8% (95% confidence
Society for Gastrointestinal Endoscopy. Appropriate use of gastrointestinal endoscopy. Manchester, MA: American Society for Gastrointestinal Endoscopy, 1986. 2. Stoltenberg PH, Kirtley DW, Culp KS, LeSage GD, White JG. Are diminutive colorectal polyps (DCP) clinically significant? (abstr). Gastrointest Endosc 1988;34:172. AF, Lewis JH, Fleischer DE, et al. Hyperplastic colonic 3. Ansher polyps as a marker for adenomatous colonic polyps. Am J Gastroenterol84:113-117, 1989. 4. Rex DK, Lehman GA, Hawes RH, Ulbright TM, Smith JJ. Screening colonoscopy in asymptomatic average-risk persons with negative fecal occult blood tests. Gastroenterology 1991;lOO: 64-67. 5. Lieberman
D, Denberg T, Smith F. Feasibility of colonoscopic screening of asymptomatic subjects (abstr). Gastrointest Endosc 1989;35:174. 6. Provenzale D, Garrett JW, Condon SE, Sandler RS. Kisk for colon adenomas in patients with rectosigmoid hyperplastic polyps. Ann InternMed 1990;113:760-763.