Current trials and future directions of the Southwest Oncology Group Breast Cancer Committee

The first adjuvant breast cancer trial in the Southwest Oncology Group (SWOG) was initiated in 1974. The trial eventually demonstrated that combination chemotherapy with cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, and prednisone was superior to single-agent chemotherapy with melphalan in premenopausal and postmenopausal patients. Subsequently, SWOG has performed a series of adjuvant chemotherapy trials either alone or in collaboration with other cooperative groups. Over the past 5 years, SWOG has accrued more than 8000 patients to different clinical trials in primary and advanced breast cancer as well as to a series of ancillary biologic studies primarily evaluating new prognostic factors, such as hormone receptor status and flow cytometry. Current questions being addressed by SWOG breast cancer adjuvant trials include the value of doxorubicin in lymph node-negative patients, of chemoendocrine therapy in lymph node-positive premenopausal and post-menopausal patients, and of high dose chemotherapy with autologous bone marrow transplantation in high risk lymph node-positive patients. Trials in patients with metastatic disease are evaluating medical castration with the luteinizing hormone-releasing hormone agonist Zoladex (Zeneca Pharmaceuticals, Wilmington, DE), high dose chemotherapy and bone marrow transplantation, and newer agents such as paclitaxel (Taxol, Bristol-Myers Squibb, Walingford, CT). Future adjuvant trials will compare optimal sequential use of single-agent chemotherapy versus more traditional combination chemotherapy and address questions of dose intensity and the value of the addition of Taxol in the adjuvant setting. A trial using the synthetic retinoid 4-hydroxyphenylretinamide is also in the planning stage.