SABCS: Menopausal Hormone Therapy Does Not Increase Breast Cancer Risk in BRCA Carriers

FRIDAY, Dec. 12, 2025 (HealthDay News) — Use of menopausal hormone therapy (MHT) following menopause is not associated with an increased risk for breast cancer among BRCA1 and BRCA2 carriers, according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 9 to 12 in San Antonio.

Joanne Kotsopoulos, Ph.D., from the Women”s College Hospital Research and Innovation Institute in Toronto, and colleagues conducted a prospective matched analysis of MHT use following menopause (predominantly surgical) and breast cancer risk in BRCA carriers. Women who initiated MHT (exposed) after menopause were matched to women who had not initiated MHT (unexposed) by gene, year of birth, and age at menopause; data were included for 676 matched pairs.

The researchers identified 87 incident breast cancer cases in the exposed group and 128 in the unexposed group (12.9 versus 18.9 percent) after a mean follow-up of 5.6 years from the date of first MHT use in exposed women. Women who used estrogen experienced a significant reduction in the risk for breast cancer compared with unexposed matched controls (hazard ratio, 0.37). No protective or adverse effect was seen for use of estrogen plus progestogen, for progestogen alone, or for tibolone. In the 43 women who used a conjugated equine estrogen plus bazedoxifene, there were no diagnoses of breast cancer. The findings were similar for carriers of either gene.

“Our findings suggest that clinicians should take a personalized approach to menopause management for women with BRCA mutations who are suffering from the impact of surgical (or natural) menopause, if there are no contraindications for them,” Kotsopoulos said in a statement.

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