'The Proceedings of the Collaborative Group of the Americas on Inherited Colorectal Cancer' Delta Centre-Ville Hotel, Montreal, Quebec, Canada, October 10-11, 2011. Abstracts.

摘要

Background: It is known that metachronous colorectal cancer risk for Lynch syndrome patients with primary colon cancer is high and total colectomy is the preferred option [1], However if the index primary cancer is in the rectum, management advice is complicated by considerations of worsening bowel function or stoma formation. To aid surgical decision-making, we estimated the risk of metachronous colon cancer for Lynch syndrome patients who underwent either anterior resection or abdominoperineal resection for primary rectal cancer.Methods: This retrospective cohort study comprised 79 MMR gene mutation carriers (18 MLH1, 55 MSH2, 4 MSH6 and 2 PMS2) from the Colon Cancer Family Registry who had a surgical resection for their first primary rectal cancer. Age-dependent cumulative risks of metachronous colon cancer were calculated using the Kaplan-Meier method. Risk factors for metachronous colon cancer were assessed using a Cox proportional hazards regression.Results: During 866 person-years of observation (median 9 years; range 1-32 years) since diagnosis of first rectal cancer, a total of 21 (27%) carriers were diagnosed with metachronous colon cancer (incidence 24.2; 95% CI 15.8-37.2 per 1,000 person-years). Incidence for carriers who had an anterior resection (26.8; 95% CI 15.5-46.1 per 1,000 person-years) was not different from that for carriers who had an abdominoperineal resection (21.0; 95% CI 10.5-42.1 per 1,000 person-years) (P = 0.1). Cumulative risk of metachronous colon cancer was 19% (95% CI 9-31%) at 10 years, 47% (95% CI 31-68%) at 20 years and 69% (95% CI 45-89%) at 30 years after surgical resection. There was no difference in the frequency of surveillance colonoscopy between two types of surgery (one colonoscopy per 1.1 (95% CI 0.9-1.2) years after anterior resection versus one colonoscopy per 1.4 (95% CI 1.0-1.8) years after abdominoperineal resection). Conclusions: For carriers of MMR gene mutations who contract rectal cancer, the metachronous col...