Postpolypectomy Colonoscopy Surveillance Guidelines: Predictive Accuracy for Advanced Adenoma at 4 Years

摘要

Background: Lack of confidence in postpolypectomy surveillance guidelines may be a factor in the observed low adherence rates among providers. nnObjective: To assess the 2006 postpolypectomy colonoscopy surveillance guidelines, which recommend 3-year follow-up colonoscopy for individuals with high-risk adenomas (defined as ≥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. nnDesign: Analysis of prospective data from the Polyp Prevention Trial. nnSetting: United States. nnParticipants: 1905 patients who had colorectal adenomas removed at baseline screening or diagnostic colonoscopy and completed the trial. nnMeasurements: Baseline adenoma characteristics, risk-stratified according to definitions used in the guidelines, were examined as predictors for advanced adenoma recurrence. nnResults: 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. nnLimitation: Participants were self-selected and had restrictions on the degree of obesity. nnConclusion: 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. nnEditors' NotesnContextnGuidelines 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). nnContributionnThe 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. nnImplicationnThe characteristics of an adenoma are not a reliable guide to the probability of recurrence of an advanced adenoma.nn—The EditorsnnClinical practice guidelines for postpolypectomy colonoscopy surveillance have been developed by different professional societies and updated as necessary on the basis of scientific evidence (1–4). However, surveys of gastrointestinal endoscopists (5) and primary care physicians (6, 7) have consistently shown a lack of adherence to surveillance guidelines, with repeated examinations being recommended at shorter intervals than the guidelines indicate. This suggests an overuse of surveillance colonoscopy, which already constitutes approximately 24% of procedures performed in the United States (8). Nonadherence may be due to a lack of knowledge of the guidelines, medical liability concerns, financial incentives, and differing recommendations by professional societies. nnThe U.S. Multi-Society Task Force on Colorectal Cancer and the American Cancer Society jointly developed and published a consensus update for postpolypectomy surveillance guidelines in 2006 to provide more consistency among guidelines (9). Patients were stratified as having high risk or low risk for subsequent development of advanced neoplasia on the basis of adenoma characteristics at baseline. The guidelines classify patients with 3 or more synchronous adenomas or any advanced adenomas (adenomas ≥1 cm in diameter or with a villous histology or high-grade dysplasia) as high risk. Individuals found to be at high risk at baseline are to have follow-up colonoscopy in 3 years, whereas those with fewer, nonadvanced, adenomatous polyps (low-risk patients) are to have repeated examination in 5 to 10 years. The guidelines recommend 10-year follow-up evaluation for average-risk individuals (those with no adenomatous polyps). nnLack of confidence in the postpolypectomy guidelines may be a common reason for nonadherence. According to Mysliwiec and colleagues (5), approximately 80% of surveyed endoscopists indicated that published evidence was very influential in their practice, but only half the respondents indicated that practice guidelines were very influential. This response highlights a perceived disconnect between published evidence and postpolypectomy guidelines. In another survey, 17% to 21% of gastroenterologists knew the guidelines but disregarded them, opting for earlier surveillance colonoscopy (10). Merritt and colleagues (11) reported that clinical practice guidelines are often fast-tracked without an adequate evaluation of their effectiveness. Therefore, validating guidelines may increase physicians' confidence and improve adherence. Our study is a step in that direction. nnWe sought to assess the utility of the risk-based stratification recommended by the current guidelines, using data from the dietary PPT (Polyp Prevention Trial). We measured the ability of adenoma characteristics at baseline (as defined in the 2006 consensus update on postpolypectomy surveillance guidelines) to predict subsequent advanced adenoma recurrence within 4 years.