CNS Metastasis Patterns in BRCA1/2 Mutation Associated and Non-BRCA Associated Breast Cancers

Abstract

BRCA1 and BRCA2 germline mutations give rise to phenotypically distinct breast cancers (BC): triple negative (TNBC) and hormone positive, respectively. Different BC subtypes are associated with different patterns of metastasis, including propensity for central nervous system (CNS) metastasis. Purpose of this study is to compare BC recurrence patterns and CNS metastasis rate by BRCA mutation status.

This retrospective study included 332 women with confirmed BRCA mutation (30 BRCA1, 32 BRCA2, 270 negative) and diagnosed with locally recurrent or metastatic BC. BRCA1 carriers often metastasized to lung (50%) and lymph nodes (50%). BRCA2 carriers and noncarriers frequently metastasized to bone (75% and 53%, respectively). CNS disease was more common in mutation carriers (53% BRCA1, 50% BRCA2, 25% noncarriers, p<0.001). Controlling for BC subtype, BRCA1 carriers had more leptomeningeal (41% versus 4%, p<0.001), but not brain parenchymal (55% versus 35%, p=0.19), disease than noncarriers. BRCA2 carriers had higher rates of both parenchymal (35% versus 8%, p=0.001) and leptomeningeal (26% versus 9%, p=0.02) disease. In multivariable regression analysis, BRCA2 (OR 3.36, p=0.008), but not BRCA1 (OR 1.97, p=0.28), mutation was significantly associated with CNS metastasis. BRCA1/2 carriers often develop CNS disease, but only BRCA2 mutation is an independent predictor of CNS metastasis.