Hormone Replacement Therapy does not Increase Risk of Breast Cancer in Women with BRCA Mutation after BSO Treatment

By Anthony M Magliocco MD

In a large multicenter international prospective study reported in JAMA Oncology, Kotsopoulos et al found that use of hormone replacement therapy overall did not appear to increase risk the of breast cancer among women with BRCA1-mutation after prophylactic bilateral salpingo-oophorectomy; however, use of estrogen-progesterone hormone replacement therapy appeared to be associated with increased risk vs estrogen alone.

Study Specifics

The study was a prospective, longitudinal cohort study of BRCA1- and BRCA2-mutation carriers from 80 centers in 17 countries which was conducted between 1995 and 2017. There was a mean follow-up of 7.6 years. The study participants had undergone BRCA1 or BRCA2 testing for familial or other reasions.

The current study included a total of 872 BRCA1-mutation carriers with no personal history of cancer with a mean postoophorectomy follow-up of 7.6 years. Patients had a mean age of 43.4 years. the questionnaires were administered every 2 years for information on hormone replacement therapy use.

The investigators concluded,

“These findings suggest that use of estrogen after oophorectomy does not increase the risk of breast cancer among women with a BRCA1 mutation and should reassure BRCA1 mutation carriers considering preventive surgery that [hormone replacement therapy] is safe. The possible adverse effect of progesterone-containing [hormone replacement therapy] warrants further study.”

However the study also revealed that use of estrogen plus progesterone was associated with higher risk vs use of estrogen-alone hormone replacement therapy.