Objective: Sessile serrated adenomas (SSAs) are precursors to colorectal cancer (CRC). The purpose of this study is to determine the occurrence of new polyps and CRC in patients with an SSA over a 5-year follow-up interval.
Methods: This study is a retrospective chart review of patients with SSAs diagnosed at colonoscopy in 2005. Abstracted information included patient demographics, colonoscopy information, and polyp characteristics.
Results: During 2005, 34 SSAs and 5 mixed SSAs were identified in 33 patients. The mean patient age was 66 years and 58% were female. There was a family history of CRC in 45%, prior polyps in 33%, and previous CRC in 15%. The mean SSA size was 11 mm. SSAs were located proximal to the splenic flexure in 70%. Low-grade dysplasia was present in 3% of SSAs and 80% mixed SSAs. Synchronous adenomatous and hyperplastic polyps occurred respectively in 45% and 21%. High-grade dysplasia was present in 12% of the adenomas. Twenty-two patients underwent subsequent colonoscopies with 20 new SSAs and 1 mixed SSA identified. In SSAs low-grade dysplasia occurred in 10% and high-grade dysplasia in 5%. Low-grade dysplasia was present in the mixed SSA. Synchronous adenomatous and hyperplastic polyps occurred respectively in 45% and 37%. High-grade dysplasia was present in 10% of adenomas and CRC occurred in 1 (5%) patient.
Conclusions: SSAs occurred more frequently in females and in the right colon. Dysplasia occurred in a small subset of SSAs. There was a high rate of prior and subsequent CRC in patients with SSAs.