Serrated polyposis syndrome and colonoscopic surveillance: who is it safe to follow?

Abstract

Aim: To assess colorectal cancer (CRC) risk during colonoscopy surveillance in a cohort of patients with the serrated polyposis syndrome (SPS). Method(s): Colonoscopy and histology records from January 2000 to time of interview for 67 New Zealand patients, meeting WHO criteria for a diagnosis of SPS and enrolled in the Genetics of Serrated Neoplasia study, were reviewed. Polyp demographics, smoking status and family history of cancer were recorded. Result(s): Of 67 patients 18 presented with CRC (mean age 57 years, 12 Female). Only one of 18 reported a first degree relative (FDR) with CRC. Over a median follow-up of 8 years from time of surgery with an average interval of 16 months between colonoscopies, two patients developed metachronous CRC: one identified at prophylactic completion colectomy and one in association with first diagnosis of SPS 19 years following initial CRC and 30 months after a previous colonoscopy. Of 45 patients with polyps alone (mean age 48 years, 27 female) followed for a median of 9 years with an average interval of 15 months between colonoscopies, none developed CRC despite 33 having multiple pan colonic polyps. Of these 33, 70% had an adenoma, 18% a sessile serrated polyp and 53% polyps>10 mm. A FDR with CRC was reported in 14/45 (31%). Four patients with multiple pan colonic polyps and no FDR with CRC underwent prophylactic subtotal colectomy (mean age 58 years, 3 females) after being followed for a median of 5 years with an average interval between colonoscopies of 8 months. All had adenomas and one a sessile serrated polyp. No significant smoking effect was seen in any group. Histological review and molecular characterisation of polyps will be reported. Conclusion If endoscopic control is feasible, SPS patients with both multiple polyps and adenomas can be judiciously managed by frequent surveillance colonoscopy.