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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
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