[Long-term complete response in a patient with breast cancer and bone and pleura metastases after treatment with a combination of S-1 and zoledronic acid].

We report a long-term complete response (CR) in a patient with postoperative recurrent breast cancer and bone and pleura metastases after treatment with a combination of S-1 and zoledronic acid. We administered 4 courses of tri-weekly CE (epirubicin 75 mg/m2, cyclophosphamide 600 mg/m2) and 12 courses of weekly paclitaxel (80 mg/m2) as adjuvant chemotherapy. However, combination therapy with S-1 and zoledronic acid was started because of the development of bone and pleura metastases. S-1 was administered orally at 100 mg/day everyday for 2 weeks, followed by a 1-week rest interval as 1 course; 4 mg of zoledronic acid was injected every 4 weeks. After 3 cycles of treatment, the patient's tumor marker levels had decreased to normal values, and both the bone and pleura metastases had disappeared. A long-term complete response was obtained as a result of this combination therapy.