Patients with early-stage breast cancer who are treated with both chemotherapy and tamoxifen have a higher survival rate than patients who receive only tamoxifen.
But a combination of tamoxifen and ovarian suppression, treatment to stop the ovaries from functioning, did not show any additional benefits, according to two randomized clinical trials published in the April 4 Journal of the National Cancer Institute .
Survival rates improve for patients with early-stage breast cancer who receive a single method of treatment, either tamoxifen, ovarian suppression, or chemotherapy. Two international studies by the Adjuvant Breast Cancer Trials Collaborative Group were designed to test whether combining these treatments would provide additional benefits.
Judith Bliss of The Institute of Cancer Research in Sutton, England, and colleagues conducted two randomized controlled phase III clinical trials of 3,854 women with early-stage breast cancer, all of whom were treated with tamoxifen for five years. In the first trial, nearly half of the 2,144 premenopausal women were randomly assigned to receive ovarian suppression, and the other half did not. Some also received chemotherapy. In the second trial, 1,991 patients were randomly assigned to receive chemotherapy, and the other half were not. Some premenopausal women also had ovarian suppression.
The researchers found that chemotherapy treatment resulted in a modest yet sustained improvement in both relapse-free and overall survival. These improvements were especially strong in women younger than 50 years and in premenopausal women who did not receive ovarian suppression.