Risk of metachronous colorectal cancer associated with polypectomy during endoscopic diagnosis of colorectal cancer.

Background and aim: There are conflicting reports regarding the risk of metachronous colorectal cancer (CRC) subsequent to colonoscopy with polypectomy or biopsy performed concurrently with diagnostic biopsies for CRC. We aimed to establish the 5-year risk of CRC in patients who had synchronous polypectomy or biopsies during the colonoscopy at which CRC was diagnosed.

Methods: This is a single-centre retrospective case-control study of adults who underwent surgical resection for CRC over a 2-year period (January 2016 to December 2017). Colonoscopy details of interest were the location of the CRC, polypectomy and non-CRC biopsy sites. In patients with CRC at index colonoscopy, we sought associations between the occurrence of metachronous CRC and the sites from which endoscopic specimens had been obtained.

Results: Our study population comprised 225 patients with a median (IQR) age of 71 (60-77) years. Polypectomy or biopsy at a non-CRC site had been performed during the index colonoscopy in 108 patients (48%), including 83 (37%) polypectomies outside the surgical resection field. There were 8 (3.6%) metachronous CRCs: 1 (0.4%) at the site of endoscopic mucosal resection for a 15-mm sessile serrated lesion, 3 (1.3%) anastomotic site CRCs and 4 (1.8%) at other sites within the colon. There was no significant difference in the prevalence of metachronous CRC in patients who underwent polypectomy/biopsy at the index colonoscopy compared with those who did not (1.9% vs. 5.1%, p = 0.283).

Conclusion: There was no significant increased risk of metachronous CRC subsequent to synchronous polypectomy or biopsy during the colonoscopy at which CRC was diagnosed.