Removal of the ovaries (oophorectomy) plus tamoxifen, as adjuvant, or “add-on” therapy, significantly improves survival in premenopausal women with operable breast cancer, a study indicates.

This finding is particularly relevant for women in resource-poor countries where, unlike in Western countries, the breast cancer case burden mostly affects premenopausal women. Moreover, in contrast to their Western peers, patients from resource-poor countries often have limited access to chemotherapy.

The study, conducted by Dr. Richard R. Love at The Ohio State University in Columbus and colleagues, involved 709 premenopausal women with operable breast cancer from Vietnam and China who were randomized to receive adjuvant oophorectomy and tamoxifen for 5 years or to observation only. The median follow-up period was 7.0 years.

The overall and “disease-free” 5-year survival rates in the adjuvant therapy group were 78 percent and 74 percent, respectively. The corresponding rates in the observation group were significantly lower - 71 percent and 61 percent. Moreover, similar differences were still apparent at 10 years.

The survival benefit achieved with adjuvant therapy was most pronounced for women with estrogen receptor (ER)-positive breast cancer. Among these women, at 5 years, the overall and disease-free survival rates in the adjuvant therapy group were 88 percent and 83 percent, respectively, while the corresponding rates in the observation group were 74 percent and 61 percent. Once again, the differences persisted at 10 years.

The current findings support the use of adjuvant oophorectomy and tamoxifen in premenopausal women, particularly those with ER-positive tumors, the investigators conclude.

SOURCE: Journal of Clinical Oncology, January 2008.