Serrated polyposis: prospective study of first-degree relatives

Area of Science:

• Gastroenterology
• Genetics
• Oncology

Background:

• Serrated polyposis (SP) is a rare colorectal cancer (CRC) predisposition syndrome with an unknown genetic basis.
• The risk of SP and/or CRC in first-degree relatives (FDRs) of SP patients is not well-established.

Purpose of the Study:

• To determine the incidence of SP and/or CRC in FDRs of index SP cases.
• To propose appropriate colonoscopy surveillance intervals for FDRs.

Main Methods:

• Prospective study of SP patients and their FDRs from 2005-2011.
• Colonoscopy offered to FDRs aged 35+ using conventional, high-definition, and chromoendoscopy.
• Pathological assessment of samples and review of prior CRC diagnoses in FDRs.

Main Results:

• Colonoscopies were performed on 78 FDRs (82.1%) from 34 pedigrees.
• An incidence of 32% for SP was observed in FDRs, with 76% having serrated polyps proximal to the sigmoid colon.
• One CRC case was detected via screening; 44.1% of index cases had an FDR with a prior CRC diagnosis.

Conclusions:

• This prospective cohort study reports a high incidence of SP in FDRs, supporting the need for screening colonoscopy.
• Findings suggest including FDR screening in clinical guidelines for SP management.