Abstract
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.
