Hormone therapy does not increase the risk of death in postmenopausal survivors of estrogen receptor-positive (ER+) breast cancer, according to research published in the Journal of the National Cancer Institute.
The study also showed no increase in the risk of breast cancer recurrence in the overall cohort, but patients who received vaginal estrogen therapy (VET) and aromatase inhibitor (AI) treatment had an increased risk of recurrence.
The study was conducted in a cohort of postmenopausal women in Denmark who were diagnosed with early-stage, invasive, ER+ nonmetastatic breast cancer from 1997 through 2004. Patients underwent complete resection and received either no subsequent treatment or adjuvant endocrine therapy for 5 years.
The analysis included 8461 patients — 1957 who received VET, 133 who received menopausal hormonal therapy (MHT), and 6371 who received no hormone therapy. Patients who received both MHT and VET were included in the MHT group. Patients who had received VET or MHT prior to their breast cancer diagnosis were not included in the study.
At a median follow-up of 9.8 years, 16% of patients (n=1333) experienced breast cancer recurrence. There was no significant difference in the risk of recurrence for patients who had received MHT and those who had never received hormone therapy (hazard ratio [HR], 1.05; 95% CI, 0.62-1.78).
Similarly, there was no significant difference in the risk of recurrence between patients who received VET and those who never received hormone therapy (HR, 1.08; 95% CI, 0.89-1.32). However, there was a significantly increased risk of recurrence for patients who received VET and AI therapy (HR, 1.39; 95% CI, 1.04-1.85).
At a median follow-up of 15.2 years, 40% of patients (n=3370) had died. There was no significant difference in the risk of death between patients who had received MHT and those who had never received hormone therapy (HR, 0.94; 95% CI, 0.70-1.26).
Likewise, there was no significant difference in the risk of death between patients who received VET and those who never received hormone therapy (HR, 0.78; 95% CI, 0.71-0.87). And there was no significant difference in the risk of death between patients who received VET plus AI therapy and those who never received hormone therapy (HR, 0.94; 95% CI, 0.70-1.26).
“In postmenopausal women treated for early-stage ER+ BC [breast cancer], use of VET or MHT was not associated with increased risk of recurrence or mortality,” the researchers summarized. “In patients treated with VET and adjuvant AIs, we observed an increased risk of recurrence but not mortality. For early-stage BC patients receiving adjuvant AIs, vaginal estrogen therapy should be used with caution.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Cold S, Cold F, Jensen MB, Cronin-Fenton D, Christiansen P, Ejlertsen B. Systemic or vaginal hormone therapy after early breast cancer: A Danish observational cohort study. J Natl Cancer Inst. Published online July 20, 2022. doi:10.1093/jnci/djac112