Adeyinka O. Laiyemo, MD, MPH; Gwen Murphy, PhD, MPH; Paul S. Albert, PhD; Leah B. Sansbury, PhD; Zhuoqiao Wang, MS; Amanda J. Cross, PhD; Pamela M. Marcus, PhD; Bette Caan, DrPH; James R. Marshall, PhD; Peter Lance, MD; Electra D. Paskett, PhD; Joel Weissfeld, MD, MPH; Martha L. Slattery, PhD; Randall Burt, MD; Frank Iber, MD; Moshe Shike, MD; J. Walter Kikendall, MD; Elaine Lanza, PhD; Arthur Schatzkin, MD, DrPH
Lack of confidence in postpolypectomy surveillance guidelines may be a factor in the observed low adherence rates among providers.
To assess the 2006 postpolypectomy colonoscopy surveillance guidelines, which recommend 3-year follow-up colonoscopy for individuals with high-risk adenomas (defined as â‰¥3 adenomas or any advanced adenomas) and 5- to 10-year follow-up for patients with 2 or fewer nonadvanced adenomas, who are considered to be at low risk.
Analysis of prospective data from the Polyp Prevention Trial.
1905 patients who had colorectal adenomas removed at baseline screening or diagnostic colonoscopy and completed the trial.
Baseline adenoma characteristics, risk-stratified according to definitions used in the guidelines, were examined as predictors for advanced adenoma recurrence.
125 patients (6.6%) had advanced and 629 (33.0%) had nonadvanced adenoma recurrence; 1151 (60.4%) had no recurrence within 4 years of follow-up. The probability of advanced adenoma recurrence was 0.09 (95% CI, 0.07 to 0.11) among patients with high-risk adenomas at baseline and 0.05 (CI, 0.04 to 0.06) among those with low-risk adenomas at baseline. The relative risk for advanced adenoma recurrence for patients with high-risk adenomas versus those with low-risk adenomas at baseline was 1.68 (CI, 1.19 to 2.38) when advanced adenoma recurrence was compared with no advanced adenoma recurrence and 1.76 (CI, 1.26 to 2.46) when advanced adenoma recurrence was compared with no adenoma recurrence. The c-statistics for these 2 comparisons were 0.68 and 0.72, respectively.
Participants were self-selected and had restrictions on the degree of obesity.
Although the risk for recurrence of advanced adenoma within 4 years is greater for patients with high-risk adenomas at baseline than for those with low-risk adenomas, the discrimination of this risk stratification scheme is relatively low.
Guidelines for surveillance colonoscopy after removing a colon polyp recommend more frequent surveillance after a high-risk finding at baseline (an advanced adenoma or ≥3 adenomas).
The authors studied 1905 patients who had an adenoma at baseline colonoscopy and had follow-up colonoscopy at 1 year and 4 years. Overall, 6.6% had an advanced adenoma—considered to be high risk to become malignant—at 4 years. The advanced adenoma rates were 9% and 5% in patients with high-risk and low-risk adenomas at baseline colonoscopy, respectively.
The characteristics of an adenoma are not a reliable guide to the probability of recurrence of an advanced adenoma.
One hundred seventy-four patients did not complete the trial. Four patients were excluded late (no baseline adenoma), 88 died before the end of the trial (from causes unrelated to the trial), and 82 withdrew (72 did not have follow-up colonoscopy, 9 declined to participate, and 1 withdrew because of ill health).
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Douglas K. Rex
Indiana University Hospital
April 18, 2008
Post-polypectomy Surveillance Guideline
To the editors,
Laiyemo et al were critical of the discriminatory value of current post-polypectomy surveillance guidelines (1). The history of post- polypectomy practice has been to expand intervals, first from 1 to 3 years, then from 3 to 5 years in the cohort considered at lowest risk. The rationale for interval expansion is that surveillance has risk, cost, and less value in preventing cancer than baseline clearing examinations (2). We are concerned that colonoscopists will react to Laiyemo et al's findings by shortening intervals.
Several factors warrant comment. First, the guideline was based on the totality of literature relating baseline colonoscopy findings to subsequent advanced neoplasia (3). Contrary to the accompanying editorial claiming that the guideline is based on 5 studies, we identified and summarized 12 relevant studies (3). No predictor of higher risk was found in all studies (3). This may reflect that multiplicity of baseline adenomas depends on efficacy of clearing (4), that polyp size is subject to endoscopist interpretation, and that villous elements and high grade dysplasia are subject to marked interobserver variation. Thus, no single study (1) would be expected to confirm each risk factor in the guideline or to represent a definitive study. Second, the guideline does not recommend major differences in follow-up for higher vs lower risk baseline findings, consistent with mixed evidence. Thus, patients with higher risk findings are recommended to undergo colonoscopy at 3 years, and the lower risk group at 5 to 10 years. Most of the latter group undergoes colonoscopy at <= 5 years in the U.S. Third, while advanced adenomas are an accepted surrogate endpoint, they do not kill people. Shortening intervals from 5 years to 3 years to detect a 5% incidence of advanced adenomas in a lower risk cohort will not clearly reduce cancer incidence or deaths at acceptable cost and risk.
The principle limitation to the effectiveness of any surveillance guideline is variability between endoscopists in effectiveness of baseline clearing (4,5). We emphasized the importance of quality baseline examinations in the guideline (3). We believe that much more can be gained in efficacy, safety and cost reductions by improving the quality of baseline examinations than by shortening post-polypectomy intervals in patients for whom the totality of the literature indicates a low risk of advanced neoplasia over 5 years or longer.
Douglas K Rex M.D., FACP, Indiana University School of Medicine, Indianapolis, Indiana
Sidney J Winawer, M.D., FACP, Memorial Sloan-Kettering Cancer Center, New York, New York
1. Laiyemo AO, Murphy G, Albert PS, Sansbury LB, Wang Z, Cross AJ, Marcus PM, Caan B, Marshall JR, Lance P, Paskett ED, Weissfeld J, Slattery ML, Burt R, Iber F, Shike M, Kikendall JW, Lanza E, Schatzkin A. Postpolypectomy colonoscopy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years. Ann Intern Med 2008;148:419-26.
2. Zauber A, Winawer SJ, Lansdorp-Vogelaar I, van Ballegooijen M, O'Brien MJ. Effect of initial polypectomy versus surveillance polypectomy on colorectal cancer mortality reduction: micro-simulation modeling of the National Polyp Study. Am J Gastroenterol 2007;102:S558.
3. Winawer SJ, Zauber AG, Fletcher RH, Stillman JS, O'Brien MJ, Levin B, Smith RA, Lieberman DA, Burt RW, Levin TR, Bond JH, Brooks D, Byers T, Hyman N, Kirk L, Thorson A, Simmang C, Johnson D, Rex DK. Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society. Gastroenterology 2006;130:1872-85.
4. Chen SC, Rex DK. Endoscopist can be more powerful than age and male gender in predicting adenoma detection at colonoscopy. Am J Gastroenterol 2007;102:856-61.
5. Barclay RL, Vicari JJ, Doughty AS, Johanson JF, Greenlaw RL. Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. N Engl J Med 2006;355:2533-41.
Adeyinka O. Laiyemo
National Cancer Institute
May 7, 2008
Predictive accuracy of the postpolypectomy guidelines - authors' reply
We agree with Drs. Rex and Winawer that a single study is unlikely to be definitive, especially when, as they suggest, variability in clinician judgment influences the identified predictors of higher risk for advanced adenoma.
We did not, however, recommend shortening the interval of surveillance colonoscopy for the low-risk category (1). In our study, the advanced adenoma recurrence rate was 9% among the high-risk and 5% among the low-risk category at 4 years. The c-statistics from multivariate models incorporating demographic and lifestyle factors with adenoma characteristics indicated that there was not much discrimination between the 2 risk groups. Although, these finding may be interpreted as meaning we should screen both groups at 3 years, they could just as well be viewed as suggesting we should extend the surveillance interval for both groups to 5 years.
Given the cost and risk associated with colonoscopic surveillance, the challenge becomes developing interval surveillance recommendations based on risk categorization schemes with greater predictive capacity. Combining the data from completed and ongoing adenoma trials and observational studies may help achieve this goal, especially if we conduct multivariate analyses incorporating demographic and lifestyle information along with adenoma characteristics. Whether additional colonoscopy- adenoma studies are needed to achieve the desired predictability for risk assignment remains to be seen.
Adeyinka O. Laiyemo, MD, MPH Cancer Prevention Fellowship Program, Office of Preventive Oncology and Division of Cancer Prevention, National Cancer Institute
Elaine Lanza, PhD Laboratory of Cancer Prevention, Center for Cancer Research, National Cancer Institute
Arthur Schatzkin, MD, DrPH Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute
1. Laiyemo AO, Murphy G, Albert PS, Sansbury LB, Wang Z, Cross AJ, et al. Postpolypectomy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years. Ann Intern Med. 2008;148:419-26. [PMID: 18347350].
Laiyemo AO, Murphy G, Albert PS, Sansbury LB, Wang Z, Cross AJ, et al. Postpolypectomy Colonoscopy Surveillance Guidelines: Predictive Accuracy for Advanced Adenoma at 4 Years. Ann Intern Med. 2008;148:419–426. doi: 10.7326/0003-4819-148-6-200803180-00004
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Published: Ann Intern Med. 2008;148(6):419-426.
Colonoscopy/Sigmoidoscopy, Gastroenterology/Hepatology, Hematology/Oncology.
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