Table 5 Factors impacting overall survival after excision of breast cancer brain metastases (significant in univariate and multivariate analysis)

Primary tumor phenotype HER2-enriched, yes vs. no

3.0 (1.1–9.9)

0.033

2.6 (1.3–5.5)

0.010

Radiotherapy after BCBM, yes vs. no

0.1 (0.0–0.2)

<0.001

0.1 (0.1–0.3)

<0.001

Endocrine therapy after BCBM excision, yes vs. no

0.1 (0.0–0.2)

<0.001

0.1 (0.0–0.3)

<0.001

HER2 IHC expression in BCBM, yes vs. no

6.5 (1.5–27.8)

0.011

4.9 (1.3–19.2)

0.020

PD-1 expression on TILs in brain, yes vs. no

0.5 (0.3–0.9)

0.015

0.3 (0.1–0.7)

0.003

Microglia/macrophages infiltration, ≥104 vs. <104 per mm²

0.6 (0.3–1.0)

0.049

0.2 (0.1–0.5)

<0.001