Advanced gastric cancer with liver metastases successfully treated with S-1

S-1 is an anticancer drug in which tegafur is combined with modulators, gimeracil and oteracil potassium. We encountered a patient with gastric cancer for whom oral administration of S-1 was effective, and we report this case. A 79-year-old woman visited our hospital with a major complaint of anorexia. Tests revealed severe anemia, with a hemoglobin (Hb) level of 6.5 g/dl, and the patient was admitted to the hospital for treatment. The primary lesion was a large type-1 gastric cancer (poorly differentiated adenocarcinoma) in the middle gastric body. In addition, a lesion with a diameter of 50 mm was observed in the left hepatic lobe and small metastatic lesions were also scattered in the right lobe. When a performance status (PS) of 0 was obtained after her systemic condition had been improved, S-1 was started, at a dose of 80 mg/day (with one course consisting of administration for 4 weeks, followed by 2 weeks' rest). No severe adverse drug reaction was observed. After one course of administration was completed, the patient received administrations at the outpatient clinic. Upon the completion of two courses, computed tomography (CT) showed disappearance of the metastatic lesions and marked regression of the primary lesion. At present, upon completion of the sixth course, no hepatic metastasis is observed and the primary gastric lesion shows a tendency to regress. Her PS is maintained at 0.