HRT Not Associated with Lower Survival After Breast Cancer

 SAN DIEGO—Hormone replacement therapy (HRT) did not shorten survival in women who received it after surviving breast cancer, Wendy R. Brewster, MD, reported in a plenary presentation at the 31st annual meeting of the Society of Gynecologic Oncologists (SGO).

“This study did not permit control of other prognostic breast cancer survival factors such as estrogen-receptor status or other comorbid conditions. However, this analysis does not suggest that hormone replacement therapy after treatment of breast cancer is associated with an adverse outcome,” said Dr. Brewster, of the University of California, Irvine.

In fact, the researchers found that breast cancer survivors who received HRT had a significant survival advantage, compared with their matched controls (P = .003). The odds ratio for risk of death was 0.28 (95% CI: 0.11 to 0.71) for the HRT group, compared with controls. This finding is somewhat surprising in view of the established role of estrogen in promotion of some types of breast cancer.

“Overall survival from all causes is impacted by HRT,” Dr. Brewster told ONI in an interview. “Patients should not be categorically denied HRT. Instead, the risks and benefits must be weighed and discussed in each case.”

This retrospective study included a cohort of 125 women who had received HRT after a diagnosis of breast cancer. The investigators identified 362 matched control subjects from a regional cancer registry. Controls were eligible if they were alive at the time HRT was initiated in the case patient and if they had not received HRT. Matching criteria included age at diagnosis, stage of breast cancer, and year of diagnosis. The mean age of cases was 51.9 years.

Ninety percent of the cases (123 women) received systemic estrogen, and 72% (90 women) received a progestational agent. The median interval between breast cancer diagnosis and beginning of HRT was 46 months, and mean duration of HRT was 22 months.

More Endometrial Cancers

There were more endometrial cancers in the HRT group than in the controls (6 vs 0). Dr. Brewster said that the statistical significance of this difference in endometrial cancer occurrence in breast cancer survivors was not calculated.

Senior investigator for the study was Philip J. DiSaia, MD, who also reported data on the use of estrogen replacement after treatment for endometrial cancer).