Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, The University of Melbourne, Parkville, Victoria, Australia.
Ann Surg Oncol. 2013 Jun;20(6):1829-36. doi: 10.1245/s10434-012-2858-5. Epub 2013 Jan 29.
Despite regular surveillance colonoscopy, the metachronous colorectal cancer risk for mismatch repair (MMR) gene mutation carriers after segmental resection for colon cancer is high and total or subtotal colectomy is the preferred option. However, if the index cancer is in the rectum, management decisions are complicated by considerations of impaired bowel function. We aimed to estimate the risk of metachronous colon cancer for MMR gene mutation carriers who underwent a proctectomy for index rectal cancer.
This retrospective cohort study comprised 79 carriers of germline mutation in a MMR gene (18 MLH1, 55 MSH2, 4 MSH6, and 2 PMS2) from the Colon Cancer Family Registry who had had a proctectomy for index rectal cancer. Cumulative risks of metachronous colon cancer were calculated using the Kaplan-Meier method.
During median 9 years (range 1-32 years) of observation since the first diagnosis of rectal cancer, 21 carriers (27 %) were diagnosed with metachronous colon cancer (incidence 24.25, 95 % confidence interval [CI] 15.81-37.19 per 1,000 person-years). 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. The frequency of surveillance colonoscopy was 1 colonoscopy per 1.16 years (95 % CI 1.01-1.31 years). The AJCC stages of the metachronous cancers, where available, were 72 % stage I, 22 % stage II, and 6 % stage III.
Given the high metachronous colon cancer risk for MMR gene mutation carriers diagnosed with an index rectal cancer, proctocolectomy may need to be considered.
尽管定期进行监测性结肠镜检查，但对于因结肠癌行节段切除术后错配修复（MMR）基因突变携带者而言，其同时性结直肠癌的风险仍然较高，全结肠切除或次全结肠切除是首选治疗方案。但是，如果原发肿瘤位于直肠，那么考虑到肠功能受损，治疗决策会变得复杂。我们旨在评估因直肠原发癌行直肠切除术的 MMR 基因突变携带者发生同时性结肠癌的风险。
本回顾性队列研究纳入了来自结肠癌家族登记处的 79 名种系 MMR 基因突变携带者（18 名 MLH1、55 名 MSH2、4 名 MSH6 和 2 名 PMS2），这些患者因直肠原发癌行直肠切除术。采用 Kaplan-Meier 法计算同时性结肠癌的累积风险。
在首次诊断为直肠癌后中位 9 年（1-32 年）的观察期间，21 名（27%）患者被诊断患有同时性结肠癌（发病率为 24.25/1000 人年，95%置信区间[CI]为 15.81-37.19）。10 年、20 年和 30 年时的累积同时性结肠癌风险分别为 19%（95%CI 9-31%）、47%（95%CI 31-68%）和 69%（95%CI 45-89%）。结肠镜检查的监测频率为 1.16 年/次（95%CI 1.01-1.31 年）。可获得同步性癌症 AJCC 分期的病例中，72%为Ⅰ期，22%为Ⅱ期，6%为Ⅲ期。
鉴于诊断为直肠原发癌的 MMR 基因突变携带者同时性结肠癌的风险较高，可能需要考虑行直肠结肠切除术。
