Table 2.

Cohort sizes and effect on hazard ratio (“HR”) for overall survival (“OS”) and brain-specific progression-free survival (“bsPFS”) for all explanatory variables studied.

	n	HR for bsPFS(95% CI)	univariable p-value for bsPFS	HR for OS (95% CI)	univariable p-value for OS
Extracranial Metastasis (any vs none)	671	0.97 (0.66, 1.45)	0.9	1.13 (0.56, 2.27)	0.7
Bone Metastasis (any vs none)	659	1.00 (0.79, 1.27)	1	1.18 (0.77, 1.82)	0.4
Lung Metastasis (any vs none)	653	1.15 (0.92, 1.43)	0.2	1.71 (1.14, 2.57)	0.008
Liver Metastasis (any vs none)	649	1.10 (0.89, 1.37)	0.4	1.91 (1.28, 2.85)	0.001
Lymph Node Metastasis (any vs none)	653	0.91 (0.73, 1.14)	0.4	1.32 (0.88, 1.99)	0.2
Leptomeningeal Disease (yes vs no)	659	1.34 (1.06, 1.69)	0.01	1.50 (1.01, 2.23)	0.04
Multiple Brain Metastases (yes vs no)	490	1.43 (1.04, 1.96)	0.02	1.56 (0.87, 2.80)	0.1
HER2+ Tumour (yes vs no)	589	0.81 (0.65, 1.02)	0.07	0.51 (0.33, 0.78)	0.001
Triple Negative Tumour (yes vs no)	589	1.28 (0.99, 1.65)	0.05	1.56 (1.01, 2.41)	0.04
Age (≥60 vs <60)	683	1.23 (0.99, 1.53)	0.06	1.71 (1.17, 2.48)	0.004
KPS Score (≤60 vs >60)	331	1.64 (1.16-2.33)	0.003	3.12 (1.85, 5.26)	6 × 10-6
Neurological Symptoms (any vs none)	646	1.32 (1.01, 1.74)	0.04	1.76 (1.02, 3.02)	0.03
Stereotactic Radiosurgery (yes vs no)	683	0.77 (0.60, 0.99)	0.03	0.40 (0.24, 0.69)	4 × 10-4
Neurosurgery (yes vs no)	683	0.90 (0.66, 1.23)	0.5	0.27 (0.11, 0.66)	0.002
Whole-brain Radiotherapy (yes vs no)	683	1.23 (0.98, 1.54)	0.06	2.77 (1.72, 4.46)	8 × 10-6

Cohort sizes listed for each variable exclude patients for whom data for that variable was unavailable.