Survival Outcome and Risk of Metachronous Colorectal Cancer After Surgery in Lynch Syndrome.

BACKGROUND: The survival benefit of extensive colectomy is controversial in Lynch syndrome, and risk factors for metachronous colorectal cancer (CRC) after segmental colectomy are unclear. OBJECTIVE: The aim of this study was to investigate the survival outcome and risk of metachronous CRC after surgery in Lynch syndrome patients diagnosed with their first CRC. METHODS: Overall, 106 patients with Lynch syndrome who underwent surgery for CRC were included in the study. The demographics, genotype, clinicopathological characteristics of the index CRC, and follow-up data were reviewed from a single-institution Lynch syndrome database. RESULTS: Of 30 patients who underwent extensive surgery, no metachronous CRC was developed during a mean follow-up of 68.1 months. Of 76 patients who underwent segmental colectomy, 13 (17.1 %) developed metachronous CRC during a mean follow-up of 77.2 months. The cumulative risk of metachronous CRC was 8.4 % at 5 years and 20.4 % at 10 years after segmental colectomy. No difference in overall and CRC-specific survival was observed between segmental colectomy and extensive colectomy (p = 0.277 and p = 0.659, respectively). A 25 cm or longer resection of bowel decreased the risk of metachronous CRC after segmental colectomy compared with less extensive resection (hazard ratio 0.10, 95 % confidence interval 0.01-0.86). Annual surveillance colonoscopy did not decrease the risk of metachronous CRC compared with less frequent surveillance colonoscopy. Although not statistically significant, none of the MSH6 gene mutation carriers were diagnosed with metachronous CRC. CONCLUSIONS: Although no survival benefit was identified, surgeons and patients might consider extensive colectomy to prevent metachronous CRC in Lynch syndrome patients regardless of their clinicopathological characteristics.