[A Case of Sigmoid Rectal Cancer with a Vesicoconstrictor Fistula Curatively Resected after Neoadjuvant Chemotherapy].

A 50-year-old man presented with fecaluria and was diagnosed with sigmoid colon cancer with a colovesical fistula. Total bladder resection was determined to be necessary for curative resection at the time of diagnosis. In anticipation of bladder preservation, 6 courses of mFOLFOX6 plus panitumumab were administered after transverse colostomy, resulting in marked tumor regression and a decision to proceed with surgery. The patient underwent robotic-assisted low anterior resection of the rectum and partial cystectomy, which yielded pathological radical treatment. We report a case of sigmoid colon cancer with a colovesical fistula complicated by bladder invasion, in which preoperative chemotherapy was effective and total cystectomy was avoided, allowing bladder preservation.