Breast density changes after risk-reducing salpingo-oophorectomy in women with a pathogenic germline variant in BRCA1 or BRCA2.

Abstract

RESULTS

Mean PD at first mammogram was 26.8% ± 15.3 (RRSO) and 31.3% ± 18.1 (no RRSO). In a median 1.1 years between mammograms, PD decreased on average 0.9% (95% CI: -1.6; -0.2) among women who did not undergo RRSO in the interval between mammograms compared to 5.9% (95% CI: -7.4; -4.5) among women who underwent RRSO in the interval (adjusted difference: -5.9%, 95%CI: -9.5; -2.2, p=0.002). Results were driven primarily by MD changes among BRCA2 PGV carriers. Use of HRT after RRSO attenuated the decline in PD.

IMPACT

Decrease in mammographic density may inform the potential protective effect of RRSO against breast cancer.

METHODS

From five studies of the international IBCCS consortium, we included 691 participants who had two or more screening mammograms available, were less than 47 years at time of RRSO (N=208) or premenopausal at all mammograms without RRSO (N=483). MD metrics [Percent density (PD), dense area (DA), and non-dense area (NDA)] were quantified using STRATUS. Multivariable linear mixed models assessed changes in MD metrics between groups, adjusting for confounders.

BACKGROUND

We studied change in mammographic density (MD) among premenopausal women with a pathogenic germline variant (PGV) in BRCA1 or BRCA2 genes, comparing those who did and did not undergo risk-reducing salpingo-oophorectomy (RRSO) in the interval between mammograms, accounting for changes in exogenous oral contraceptive (OC) or hormone replacement therapy (HRT) use.

CONCLUSIONS

On average, PD and DA decrease following RRSO in premenopausal carriers, particularly among BRCA2 PGV carriers. HRT formulation affects MD changes.