[A case with local recurrence of rectal cancer that responded to S-1 and PSK with long-term complete response]

The patient was a 65-year-old male, who underwent low anterior resection for rectal cancer. The pathological diagnosis showed mucinous adenocarcinoma, pSS, and pN0. He complained of diarrhea and melena 4 months after the surgery. Abdominal computed tomography and colonofiberscopy showed a local recurrence of rectal cancer. Because the tumor was diagnosed as unresectable, combined chemotherapy of S-1 (100 mg/day, per os, 4 weeks of treatment and 2 weeks of rest) and PSK (3 g/day, per os, the same schedule as S-1) was started. After the 2 courses of chemotherapy, computed tomography and colonofiberscopy showed a complete disappearance of the tumor. The chemotherapy was continued until the 9th course and then stopped. Five years and 4 months since the induction of a complete response, the patient is still alive without disease recurrence. Combined chemotherapy of S-1 and PSK may be one of useful choices for recurrent colorectal cancer.