WESTPORT, Jun 25 (Reuters Health) - Adding a single cycle of low-dose chemotherapy to tamoxifen therapy does not improve survival in women with stage II, hormone-receptor-positive breast cancer.
In the June issue of the Journal of Clinical Oncology, researchers report that chemotherapy failed to improve either overall or disease-free survival after a median of 7.5 years of follow-up. They randomized 613 patients with stage II hormone-receptor-positive breast cancer to daily tamoxifen therapy, 20 mg for 2 years, plus either one cycle of low-dose chemotherapy or no chemotherapy.
Patients randomized to the chemotherapy regimen received, intravenously, "...on day 1, doxorubicin 20 mg [per meter squared] and 1 mg [per meter squared] vincristine; on days 29 and 36, cyclophosphamide 300 mg [per meter squared], methotrexate 25 mg [per meter squared], and fluorouracil 600 mg [per meter squared]," according to the report.
Disease-free survival was similar in the two treatment groups: 62% in patients receiving chemotherapy and 60% in those treated with tamoxifen alone, Dr. Raimund Jakesz, of the University of Vienna in Austria, and the Austrian Breast Cancer Study Group report. Overall survival was approximately 60% in both groups.
Factors associated with disease-free survival included menopausal status, nodal status, progesterone receptor status and histologic grade. For overall survival, prognostic factors included nodal and tumor stage, tumor grade and hormone receptor level.
Survival among patients in a control group, consisting of 79 postmenopausal women who received no treatment, was "virtually identical" to survival in premenopausal women treated with tamoxifen alone, Dr. Jakesz and colleagues point out.
Survival in both groups was significantly inferior to survival in tamoxifen-treated postmenopausal patients. According to the research team, this finding lends support to "...the hypothesis of a more pronounced effect of tamoxifen in the older age groups."
The results do not preclude the possibility that full-dose chemotherapy may be of use in these patients, the investigators say. "Future clinical trials should formulate more specific questions," they conclude, "...to obtain more specific answers."
J Clin Oncol 1999;17:1701-1709.