(HealthDay News) — While tamoxifen plus ovarian suppression does not provide a significant benefit over tamoxifen alone among premenopausal women with hormone receptor-positive early breast cancer, the addition of ovarian suppression does benefit some of these women, and exemestane plus ovarian suppression further improves disease outcomes, according to new research. The findings were published online Dec. 11 in the New England Journal of Medicine to coincide with the annual San Antonio Breast Cancer Symposium, held from Dec. 9 to 13 in San Antonio.
Prudence A. Francis, M.D., from the University of Melbourne in Australia, and colleagues examined the role of adjuvant ovarian suppression in hormone receptor-positive early breast cancer recurrence. The authors randomized 3,066 premenopausal women, classified according to prior receipt or nonreceipt of chemotherapy, to five years of tamoxifen, tamoxifen plus ovarian suppression, or exemestane plus ovarian suppression.
After a median follow-up of 67 months, the researchers found that the estimated five-year disease-free survival was not significantly different between the tamoxifen-ovarian suppression and the tamoxifen groups (86.6 and 84.7 percent, respectively; hazard ratio, 0.83; 95 percent confidence interval [CI], 0.66 to 1.04; P = 0.10). Most recurrences occurred in women who had previously received chemotherapy; at five years, the rate of freedom from breast cancer was 82.5 and 78.0 percent in the tamoxifen-ovarian suppression group and the tamoxifen group, respectively (hazard ratio for recurrence, 0.78; 95 percent CI, 0.60 to 1.02). In the exemestane-ovarian suppression group, the rate of freedom from breast cancer at five years was 85.7 percent (hazard ratio for recurrence versus tamoxifen, 0.65; 95 percent CI, 0.49 to 0.87).
“Adding ovarian suppression to tamoxifen did not provide a significant benefit in the overall study population,” the authors write. “However, for women who were at sufficient risk for recurrence to warrant adjuvant chemotherapy and who remained premenopausal, the addition of ovarian suppression improved disease outcomes. Further improvement was seen with the use of exemestane plus ovarian suppression.”
The study was partially funded by Pfizer and Ipsen.