Metachronous CRC Risk in Lynch Syndrome: Clinical Gastroenterolo and Hepatolo, March 2026

Introduction

Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRC) syndrome, caused by germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM). Individuals with LS have a markedly increased lifetime risk of CRC and frequently develop metachronous colorectal cancer after treatment of the first tumor. Surgical strategy—segmental (partial) colectomy vs extended colectomy—is therefore a critical decision that must balance cancer prevention with postoperative quality of life.

Summary

This multicenter cohort study from the German Consortium for Familial Intestinal Cancer analysed 852 patients with Lynch syndrome who underwent surgery for primary CRC to determine risk factors for metachronous CRC.

Over a median follow-up of 7.9 years, 21.1% of patients developed a second colorectal cancer.

Key findings included:

Partial colectomy showed a trend toward a higher risk of metachronous CRC compared with extended colectomy in high-risk LS carriers (HR 3.78; borderline significance).

Male sex significantly increased risk (HR 2.16).

Older age at first CRC diagnosis modestly increased risk (HR 1.03 per year).

Left-sided primary tumors were associated with higher metachronous risk (HR 1.53).

Surveillance colonoscopy adherence did not significantly reduce risk in this analysis.

Key Message

Metachronous CRC remains common in Lynch syndrome despite surveillance. Risk varies according to sex, age, tumor location, and possibly extent of surgery, supporting a personalized surgical strategy rather than a uniform recommendation for extended colectomy in all patients.