[A patient with advanced remnant gastric cancer responding completely to S-1 monotherapy].

A 74-year-old man with anemia visited our hospital. When he was 42 years old, he was diagnosed with duodenal ulcer and underwent gastrectomy with Billroth II construction. A gastrointestinal endoscopic examination revealed an ulcerative lesion at the remnant stomach, and the pathological examination of the biopsy specimen showed moderate to poorly differentiated adenocarcinoma. Abdominal CT scan revealed liver and para-aortic lymphnode metastases. He received daily oral administration of S-1 at a dose of 100 mg/body, bid, 4 weeks on and 2 weeks off. After 4 courses of S-1, CT scan showed a complete response of the liver and also para-aortic lymphnode metastasis. He underwent total remnant gastrectomy with D2 dissection. Histological examination revealed no residual cancer cells in the surgically removed stomach and lymphnode, and he was diagnosed a complete pathological response (Grade 3). He refused adjuvant S-1, but is in good health without recurrence 2 years after the operation.