Introduction Piecemeal endoscopic mucosal resection (pEMR) is a minimally invasive endoscopic technique for the resection of sessile/flat colorectal polyps (larger than 2 cm). It has been suggested that patients should have a check procedure at 3 or 6 months to ensure complete initial excision of the lesion, and subsequent colonoscopic surveillance at between 1 and 3 years to identify recurrence.

Methods This is a retrospective observational audit, including all patients with sessile/flat colorectal polyps of more than 20 mm in diameter who underwent pEMR in 2010, across 4 London Teaching Hospitals. Patients were either local or tertiary referrals. Data was obtained from colonoscopy and histology reports. The primary outcome measured was the follow up rate at first, check colonoscopy (3 months, 6 months or 1 year), and at the subsequent surveillance colonoscopy (1, 2 or 3 years). Recurrence rate at both check and surveillance was a secondary outcome. A high-risk recurrence was considered to be more than or equal to 10 mm and a low-risk recurrence less than 10mm.

Results 153 patients were included in the cohort; 53 (34.6%) patients were local referrals and 100 (65.4%) were tertiary referrals. 128 (83.6%) patients had a check colonoscopy and 74 patients (49.0%) had a surveillance colonoscopy. Adenoma recurrence occurred in 44 (34.4%) patients at check colonoscopy, with 3 (2.4%) polyps having high-risk recurrence, and in 12 (16.3%) patients at surveillance colonoscopy, with 3 (4.1%) polyps having high-risk recurrence. Of the patients with recurrence at surveillance, 5 (41.6%) also had polyp recurrence at check colonoscopy, equating to failure to clear the initial recurrence in 11.4%. In 7 patients the check colonoscopy showed no recurrence.

Conclusion The rate of check colonoscopy within our cohort was high, but the rate of surveillance colonoscopy was low. The frequency of adenoma recurrence was considerable at the check colonoscopy, but much reduced at the surveillance colonscopy. There was, however, a low rate of high-risk recurrence, suggesting that pEMR is an effective endoscopic technique to excise sessile/flat polyps as, in most cases, treatment of recurrence at the check colonoscopy was effective. A substantial proportion of individuals with recurrence at surveillance had recurrence at check colonoscopy, but recurrence was found at surveillance despite a normal check procedure. Strict adherence to follow-up protocols is, therefore, essential.

Disclosure of Interest None Declared.