[Successful TS-1 therapy in a patient with non-resectable gastric cancer and renal dysfunction].

A 73-year-old woman presented to our hospital with epigastric pain and swelling of the left upper limb. Enlarged lymph nodes with adhesion were palpable in the left cervical region and supraclavicular fossa. Tests were performed with the thought that the left upper limb swelling was secondary to venous compression by the enlarged lymph nodes. Gastroscopy detected a torose lesion on the anterior wall at the gastric angle and biopsy revealed that it was moderately differentiated adenocarcinoma. MRI showed metastasis to the sixth cervical vertebra and the first thoracic vertebra. Based on these findings, she was diagnosed as having progressive gastric cancer with metastasis to Virchow's lymph node and the cervical and thoracic vertebrae. Because it was considered impossible to perform radical gastrectomy, chemotherapy was given. Since renal dysfunction was suggested by a serum Cr of 1.5 mg/ml and a Ccr of 26.2 ml/min, TS-1 was administered at a lower dose (50 mg/day for 4 weeks) than usual, followed by 2 weeks off therapy to complete 1 course. During TS-1 therapy, the plasma 5-FU concentration at 4 h was 129.5 ng/ml, indicating that an effective plasma level of the drug was achieved. TS-1 therapy was considered effective because it reduced the diameter of the primary tumor and the lymph node metastasis, with only mild adverse reactions including myelosuppression.