En bloc endoscopic mucosal resection is equally effective for sessile serrated polyps and conventional adenomas.

ABSTRACT

BACKGROUND: Sessile serrated polyps (SSPs) are associated with higher rates of incomplete resection compared to conventional adenomas after traditional snare polypectomy. Outcomes after endoscopic mucosal resection (EMR) are less established. The aim of this study was to evaluate the rate of residual neoplasia at surveillance colonoscopy for SSPs compared to conventional adenomas ≥ 10 mm after en bloc EMR. METHODS: Retrospective cohort study of consecutive patients referred for EMR of a colonic lesion ≥ 10 mm from 2005 to 2013. Data on procedures, histopathology, and surveillance colonoscopies were recorded. The primary outcome was rate of macroscopically evident residual neoplasia at surveillance colonoscopy for SSPs compared to adenomas. Secondary outcomes included rate of neoplasia at the resection margin. RESULTS: 283 consecutive patients with 293 polyps underwent en bloc EMR including 101 SSPs and 192 adenomas. Pathology commented on the lateral resection margins of the specimen in 235 cases (80%). Of these, neoplasia was noted at the resection margin in 29/64 SSPs (45.3%) compared to 65/171 adenomas (38.0%; P = .37). Surveillance data were available for 153 index lesions with a median interval of 13 months (interquartile range, 10.75-23.25 months). Ten resection sites (6.5%) were found to have residual neoplasia, including 2/52 SSPs (3.8%) and 8/101 adenomas (7.9%; P = .50). Of the cases with surveillance data 128/153 (84%) commented on the lateral margin of the resection specimen. Residual neoplasia was noted in 3/68 lesions (4.4%) with negative margins compared to 5/60 lesions (8.3%) with positive margins (P = .47). CONCLUSIONS: En bloc EMR for colonic lesions ≥ 10 mm is associated with a 6.5% rate of macroscopic residual neoplasia. Although 45% of SSPs had neoplasia extending to the resection margin, rates of residual neoplasia at surveillance colonoscopy were low. These results suggest that when feasible en bloc EMR is a reasonable option to resect SSPs ≥ 10 mm.