Snaring large serrated polyps

Serrated polyps of the large bowel are potentially premalignant, difficult to see, but important to remove. Few studies describe the technique or outcomes of serrated polypectomy. We sought to present outcomes of a series of polypectomies of large serrated polyps in comparison to a series of endoscopic resections of large adenomas.

This retrospective, comparative, single endoscopist study was performed in an outpatient colonoscopy department of a tertiary referral medical center. Patients had outpatient colonoscopy where a large (≥2 cm) serrated polyp or adenoma was removed. Outcomes were completeness of excision and complications of polypectomy. A database of endoscopic polypectomies was reviewed. Polypectomy of large serrated polyps was compared with polypectomy of large adenomas.

There were 132 large serrated polyps in 112 patients and 563 adenomas in 428 patients. More serrated polyps were right sided (120 of 130, 92.3 %, vs. 379 of 563, 67 %) (p < 0.0001). The serrated polyps were smaller than the adenomas (mean 25.5 ± 7.9 mm standard deviation) versus 36.8 ± 16.9 mm standard deviation (p < 0.001). There were four complications of serrated polypectomy in four patients (4 % of polyps, 5 % of patients): three postpolypectomy bleeds and one postpolypectomy syndrome. There were 33 complications of adenoma removal (31 postpolypectomy bleeding and two postpolypectomy syndrome) (6.9 % of polyps, p = 0.376, 8.4 % of patients, p = 0.371). On follow-up, 36 of 51 patients (71 %) with serrated polyps had metachronous lesions compared to 133 of 298 patients (45 %) with adenomas (p < 0.0001). There were fewer residual polyps in the serrated group (4 of 47 vs. 64 of 298, p = 0.001).

Removal of large serrated colorectal polyps is no more complicated than polypectomy of similarly sized adenomas. However, large serrated polyps have a higher rate of metachronous polyps than similarly sized adenomas and surveillance should be adapted to reflect these findings.