[A case of sigmoid colon cancer with multiple liver metastases responding to S-1]

A 74-year-old woman was referred to our hospital with complaints of constipation and abdominal distention caused by a sigmoid colon tumor. After examination, she was diagnosed as sigmoid colon cancer with multiple liver metastases. To prevent bowel obstruction, a sigmoid colon resection was performed. On postoperative days 15, S-1 was started, and she was discharged on postoperative day 26. Each course consisted of daily oral administration S-1 for 4 weeks followed by 2 drug-free weeks. However, because of grade 2 anorexia in the 1st course, the treatment plan was changed to administration for 2 weeks and withdrawal for 1 week. After 7 courses of treatment, computed tomography revealed that the liver metastases were remarkably reduced. Although she experienced an adverse event involving a cutaneous symptom of grade 2, the treatment was continued under ambulatory management. After eight courses, elevation of tumor marker and metastasis at the right femur were found, and she died of the cancer 12 months after the operation. S-1 is expected to be an effective agent for the treatment of advanced colorectal cancer.