[Clinical study of individual TS-1 therapy for inoperable gastric cancer]

TS-1 is a novel oral anticancer drug that is a formation of 5-FU. It consists of tegafur, CDHP (which inhibits 5-FU degradation enzyme), and Oxo (which reduces gastrointestinal toxicities) for an increased anticancer effect. We applied individual TS-1 therapy in 22 cases (cs) of inoperable gastric cancer and studied the clinical and adverse effects. Patients were treated with daily oral administration of 80-100 mg TS-1 for 4 weeks, followed by a rest for 1 or 2 weeks. The response rate was found to be 27.3% (6/22) (PR: 6 cs, NC: 4 cs, PD: 10 cs, NE: 2 cs). Overall, the median survival time was 8.2 months and the one-year survival rate was 23.6%. By location, the response rate of the primary lesion was 27.3% (6/22), abdominal lymph node metastasis 18.8% (3/16), and liver metastasis 33.3% (4/12). There was no significant difference in the response rate by tissue type. A comparison by whether or not patients had undergone previous chemotherapy revealed a response rate of 37.5% (6/16) in patients who had undergone previous chemotherapy, and 0% (0/6) in those who had not. The prevalence of adverse effects was 68.2% (15/22), with the main adverse effects being myelosuppression, pigmentation and appetite loss. However, adverse effects with a grade of more than 3 occurred in only one case of neutropenia. We could observe the course of all patients on an outpatient basis.