Brain metastases after breast-conserving therapy and systemic therapy: incidence and characteristics by biologic subtype

The characteristics of brain metastases (BM) that develop after breast-conserving therapy (BCT) for early-stage breast cancer (BC) remain incompletely defined. We examined 1,434 consecutive patients with stage I/II invasive BC who received BCT from 1997 to 2006, 91 % of whom received adjuvant systemic therapy, according to BC subtype. Median follow-up was 85 months. Overall 5-year cumulative incidence of BM was 1.7 %; 0.1 % for luminal A, 3.3 % for luminal B, 3.2 % for luminal-HER2, 3.7 % for HER2, and 7.4 % for triple negative (TN). Women who developed BM were more likely at BC diagnosis to be younger ( P