Cancer Research Lab

Adjuvant oophorectomy and tamoxifen significantly improve overall and disease-free survival in premenopausal women with operable breast cancer, according to a report in the Journal of Clinical Oncology for January.

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 cytotoxic 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% and 74%, respectively. The corresponding rates in the observation group were significantly lower — 71% and 61%. Moreover, similar differences were still apparent at 10 years.

The survival benefit achieved with adjuvant therapy was most pronounced for women with ER-positive tumors. Among these women, at 5 years, the overall and disease-free survival rates in the adjuvant therapy group were 88% and 83%, respectively, while the corresponding rates in the observation group were 74% and 61%. 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.