[Surgery for Anal Canal Squamous Cell Carcinoma after Prostate Brachytherapy-A Case Report].

Generally, the first treatment plan for anal canal squamous cell carcinoma(SCC)is chemo-radiation therapy(CRT). We experienced an extremely rare surgery case of anal canal SCC after prostate brachytherapy. A man in his 70s who had undergone brachytherapy for prostate cancer 8 years before visited our hospital because of blood in feces. A tumor prolapsed from the anal verge, and biopsy revealed SCC. Contrast-enhanced computed tomography showed front-wall thickness in the lower rectum, but we could not evaluate it in detail because of the halation by brachytherapy seeds. We performed laparoscopic abdominoperineal resection to avoid an overdose of radiation for the rectum. Pathological staging was pT2N1aM0, pStage ⅢA. These findings might suggest radiation-induced cancer after brachytherapy.