A case of metastatic breast cancer achieving complete response by combination therapy with 5'-deoxy-5-fluorouridine and cyclophosphamide

Recently there have been several reports on the effectiveness of combination chemotherapy with 5'-deoxy-5-fluorouridine (5'-DFUR) and cyclophosphamide (CPA) for treating recurrent breast cancer. We report a case in which treatment of local recurrence and lung metastases responded was remarkably effective by this combination chemotherapy. A 45-year-old woman underwent modified radical mastectomy for left breast cancer (T2N0M0) three years previously. Involvement of a left supraclavicular lymph node (ScLN) and multiple lung metastases were revealed 2 years and 6 months after the operation. First, we opted for systemic endocrine therapy with local irradiation for the lung metastases and ScLN. However the lung metastases were found to have increased on chest x-ray 2 months after treatment, showing progressive disease (PD). A locally recurrent new lesion sized 2 x 2 cm had also developed. Thus, we changed the treatment to combination chemotherapy with 5'-DFUR 800 mg/body and oral CPA 100 mg/body once a day. The lung metastases had disappeared on chest x-ray and the local recurrence was not palpable after 7 weeks of the new treatment. Thymidine phosphorylase (dThdPase) immunostaining of the primary tumor was strongly positive in almost all cancer cells. We discuss the mechanism of the increased efficacy of combination chemotherapy with 5'-DFUR and CPA.