Locally Advanced Sigmoid Colon Cancer in an Elderly Patient Treated with Curative Resection after Successful Panitumumab Treatment

: An 84-year-old woman had locally advanced sigmoid colon cancer that was unresectable because of deep invasion in the left pelvic wall. Transverse double-barrel colostomy was performed owing to stenosis in the sigmoid colon. The patient's performance status score was 2, and it was difficult to administer cytotoxic chemotherapy. Single-agent panitumumab chemotherapy was initiated. In addition, although S-1 was administered for 4 days in the fourth cycle, it was discontinued owing to drug intolerance. Panitumumab was administered seven times. The tumor size markedly reduced, and sigmoid colectomy was performed. Thus, single-agent panitumumab chemotherapy is a possible treatment option for advanced colorectal cancer in elderly patients.