Therapeutic Usefulness of Postoperative Adjuvant Chemotherapy with Tegafur–Uracil (UFT) in Patients with Breast Cancer: Focus on the Results of Clinical Studies in Japan

Abstract

In Japan, the history of postoperative chemotherapy for breast cancer started with 5-fluorouracil (5-FU), launched in the 1980s. Currently, oral fluoropyrimidine–based regimens indicated for the treatment of breast cancer in Japan include tegafur plus uracil (UFT); tegafur, gimeracil, and oteracil (TS-1); doxifluridine; and capecitabine. In particular, UFT represents an important option for long-term treatment because of minimal adverse events and the potential for long-term maintenance of effective plasma concentrations of 5-FU to inhibit micrometastasis after surgery. Therefore, various clinical studies of postoperative adjuvant chemotherapy with UFT have been conducted in patients with completely resected tumors. Recent studies have shown that UFT prolongs survival after tumor resection in patients with gastric cancer, colorectal cancer, and lung cancer. In patients with breast cancer, large clinical trials of UFT-based postoperative chemotherapy conducted in Japan have shown that UFT is useful for the treatment of intermediate-risk patients with no lymph node metastasis. This paper reviews the results of clinical studies of UFT conducted in Japan to assess the therapeutic usefulness of this oral 5-FU. The types of patients most likely to benefit from UFT are discussed on the basis of currently available evidence and a global consensus of treatment recommendations. The optimal timing of endocrine therapy and strategies for postoperative adjuvant chemotherapy with UFT in patients with breast cancer are also discussed.