[A Case of Curatively Resected Rectosigmoid Colon Cancer That Invaded the Urinary Bladder after Neoadjuvant Chemotherapy].

The patient was a 65-year-old man. His complaints included bloody stools and pain on urination. A detailed examination suggested vesical wall invasion, leading to a diagnosis of rectosigmoid cancer(cT4b, N+, M0). For R0 surgery, total cystectomy was considered necessary. To maintain vesical function, tumor-reducing chemotherapy was selected. After colostomy for the sigmoid colon, 4 courses of mFOLFOX6 plus bevacizumab therapy were administered. There was a marked reduction in the tumor size; therefore, 3 courses of mFOLFOX6 plus panitumumab therapy were administered as preoperative chemotherapy before resection. Partial response(PR)was achieved, and there was no urinary bladder infiltration. Therefore, surgery was performed. There was no tumor invasion to any other organ. High anterior rectal resection was performed. The pathological diagnosis also confirmed the efficacy of chemotherapy. We report about a patient in whom extended surgery could be avoided by administering chemotherapy for advanced rectosigmoid cancer with urinary bladder invasion.