Colorectal cancer and advanced adenoma incidence during post-polypectomy surveillance: a national cohort study in the English Bowel Cancer Screening Programme.

BACKGROUND: Improved colonoscopy quality has led to debate about whether all post-polypectomy surveillance is justified. We evaluated surveillance within the English Bowel Cancer Screening Programme (BCSP) to determine the yield of surveillance and identify predictive factors for surveillance outcome. METHODS: We performed a retrospective cohort study of individuals undergoing post-polypectomy surveillance between July 2006 and January 2017. BCSP records were linked to the National Cancer Registration Database to identify interval-type post-colonoscopy colorectal cancers (CRCs). Advanced adenoma and CRC at surveillance were documented. CRC incidence was compared with the general population using standardized incidence ratios (SIRs). Predictors of advanced adenomas at first surveillance (S1), and CRC during follow-up, were identified. RESULTS: 44 151 individuals (23 078 intermediate risk; 21 073 high risk) underwent 64 544 surveillance episodes. Advanced adenoma and CRC yields were, respectively, 10.0 % and 0.5 % at S1, 8.5 % and 0.4 % at S2, and 10.8 % and 0.4 % at S3. S1 yield was lowest in those with one index adenoma ≥ 10 mm (advanced adenoma 6.1 %; CRC 0.3 %). The SIR was 0.76 (95 %CI 0.66-0.88), accounted for by the intermediate risk group (intermediate risk SIR 0.61, 95 %CI 0.49-0.75; high risk SIR 0.95, 95 %CI 0.79-1.15). Adenoma multiplicity, presence of a large nonpedunculated adenoma, and greater villous component were associated with advanced adenoma at S1. Older age and multiplicity were significantly associated with CRC risk. CONCLUSION: This large, national analysis found low levels of CRC in those undergoing surveillance and low advanced adenoma yield in most subgroups. Less intensive surveillance in some subgroups is warranted, and surveillance may be avoided in those with a single large adenoma.

Surveillance of colonic polyps: Are we getting it right?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. The identification of colonic polyps can reduce CRC mortality through earlier diagnosis of cancers and the removal of polyps: the precursor lesion of CRC. Following the finding and removal of colonic polyps at an initial colonoscopy, some patients are at an increased risk of developing CRC in the future. This is the rationale for post-polypectomy surveillance colonoscopy. However, not all individuals found to have colonic adenomas have a risk of CRC higher than that of the general population. This review examines the literature on post-polypectomy surveillance including current international clinical guidelines. The potential benefits of surveillance procedures must be weighed against the burden of colonoscopy: resource use, the potential for patient discomfort, and the risk of complications. Therefore surveillance colonoscopy is best utilised in a selected group of individuals at a high risk of developing cancer. Further study is needed into the specific factors conferring higher risk as well as the efficacy of surveillance in mitigating this risk. Such evidence will better inform clinicians and patients of the relative benefits of colonoscopic surveillance for the individual. In addition, the decision to continue with surveillance must be informed by the changing profile of risks and benefits of further procedures with the patient's advancing age.