Colonic cancer secondary to radiation therapy : dose-response relationships and genetic changes.

1946 ~ 1990年共手术治疗结直肠癌2909例。其中29例（1%）有恶性肿瘤（如子宫癌）盆腔内放疗史。从放疗结束到结直肠癌切除的平均时间为17年5个月（范围：2年6个月至35年）。组织学上，29例30个病灶中，极高分化腺癌3例（10%），高至中分化腺癌19例（63%），粘液癌（MUC）7例（24%），%）的鳞状细胞癌。5年生存率为68%。对于单独的MUC，其为100%（对于MUC未进行放射治疗，为33%）。本组MUC的发病率为24%，高于一般人群的发病率（5%）。放疗至切除间隔时间越长，MUC和放射性直肠炎的发生率越高（19例）。伴发放射性直肠炎的有腺瘤5例，异型增生5例，深部囊性结肠炎7例。我们推测，MUC在这一系列的根源主要是放射性直肠炎。

From 1946 to 1990,2909 cases of colorectal cancer were surgically treated. Twenty-nine (1%) of these had history of intrapelvic radiation for malignancy such as uterine cancer. The mean interval from the end of radiotherapy to the resection of colorectal cancer was 17 years and 5 months (range : 2 years 6 months to 35 years). Histologically, of 29 cases and 30 lesions, there were 3 cases (10%) of very well differentiated adenocarcinoma, 19 (63%) of well to moderately differentiated adenocarcinoma, 7 (24%) of mucinous carcinoma (MUC), and 1 (! %) of squamous cell carcinoma. The five year survival rate was 68%. For MUC alone, it was 100% (for MUC without radiotherapy, 33%). The 24% incidence of MUC in this series is higher than that (5%) of a general population. The longer the radiotherapy-to-resection interval, the more frequent the incidence of MUC as well as of radiation proctitis (19 cases). Associated with radiation proctitis were adenoma (5 cases), dysplasia (5 cases) and colitis cystica profunda (7 cases). We hypothesize that MUC in this series stems largely from radiation proctitis.