Table 2.

Univariate and multivariate analysis of overall survival

Variable	Univariate		multivariate
	HR (95% CI)	p Value	HR (95% CI)	p Value
Age (per year)	1.00 (0.98–1.02)	0.98	–	–
Sex
Male	1.35 (0.83–2.29)	0.23	–	–
Female	Ref.	Ref.	–	–
Group		Global p = 0.10		Global p = 0.06
No ipilimumab	Ref.	Ref.	Ref.	Ref.
Concurrent ipilimumab	0.77 (0.43–1.35)	0.37	0.60 (0.32–1.11)	0.11
Non-concurrent ipilimumab	0.55 (0.30–0.95)	0.03	0.51 (0.28–0.92)	0.02
Ipilimumab dose
3 mg/kg	Ref.	Ref.	–	–
10 mg/kg	0.72 (0.30–1.55)	0.41	–	–
Ipilimumab cycles (per cycle)	1.24 (0.91–1.73)	0.17	–	–
Pembrolizumab therapy
Yes	0.63 (0.26–1.28)	0.21	–	–
No	Ref.	Ref.	–	–
KPS
≥80	0.72 (0.45–1.17)	0.06	–	–
<80	Ref.	Ref.	–	–
DS-GPA (per unit increase)	0.60 (0.46–0.78)	< 0.001	0.69 (0.50–0.96)	0.02
Stage at diagnosis
I–II	Ref.	Ref.	–	–
III–IV	0.89 (0.48–1.71)	0.50	–	–
Time from primary cancer to brain metastasis (years)
>5	0.57 (0.35–0.92)	0.02	0.70 (0.40–1.20)	0.20
≤5	Ref.	Ref.	Ref.	Ref.
Extracranial metastases
Yes	1.36 (0.78–2.50)	0.29	–	–
No	Ref.	Ref.	–	–
Year treated with SRS
2006–2010	Ref.	Ref.	–	–
2011–2015	1.41 (0.87–2.28)	0.16	–	–
Number of brain metastases treated
1	Ref.	Ref.	Ref.	Ref.
2–4	2.35 (1.35–4.17)	0.003	1.64 (0.86–3.16)	0.13
5+	2.46 (1.27–4.69)	0.009	1.28 (0.54–3.02)	0.57
Prior WBRT
Yes	1.37 (0.57–2.81)	0.45	–	–
No	Ref.	Ref.	–	–
Prior chemotherapy
Yes	0.78 (0.46–1.28)	0.33	–	–
No	Ref.	Ref.	–	–
Prior targeted therapy
Yes	0.83 (0.52–1.33)	0.44	–	–
No	Ref.	Ref.	–	–
Prior neurosurgery
Yes	1.00 (0.61–1.61)	0.99	–	–
No	Ref.	Ref.	–	–

CI confidence interval, DS-GPA diagnosis-specific graded prognostic assessment, SRS stereotactic radiosurgery, WBRT whole-brain radiotherapy