[A case of liver metastasis successfully treated with S-1 monotherapy in the patient with recurrent breast cancer].

: We experienced a case of recurrent breast cancer resistant to prior medications, which was treated with oral S-1, a fluoropyrimidine-class anticancer drug, and exhibited the marked shrinkage of liver metastasis. The prior treatments including anthracycline and taxane were judged not effective because of the progressive disease. Then the oral treatment with S-1 was started at 120 mg/day bid. targeting metastatic lesions of the liver. At the end of the second cycle,a significant improvement was noted with a decrease rate of 82.5%. The S-1 monotherapy was thus considered to be an effective treatment for advanced or recurrent breast cancer resistant to anthracyclines and taxanes.