Table 2.

Hazard ratios for hazard of developing leptomeningeal dissemination

Univariate analysis
Clinical feature	Univariate hazard ratio (95 % CI)	p value
Age (5-year interval)	0.9 (0.8, 1.0)	0.006
Female Sex – (male, referent)	1.4 (0.8, 2.5)	0.24
Primary site of cancera
Breast	1.5 (0.8, 2.8)	0.16
Lung	0.6 (0.3, 1.0)	0.07
Melanoma	1.3 (0.6, 2.9)	0.47
Colon/rectal	2.9 (1.2, 6.7)	0.01
Genitourinary	‡
Otherb	1.4 (0.4, 4.9)	0.57
Number of metastases	1.1 (1.0, 1.3)	0.005
Distant Failure	4.1 (2.1, 7.9)	<0.0001
Surgical resection before SRS	1.1 (0.6, 2.0)	0.78
Surgical resection after SRS	‡
Whole brain radiation therapy	2.4 (1.4, 4.4)	0.003
Stepwise multivariable model
Clinical feature	Adjusted hazard ratio(95 % CI)	p value
Colorectal primary sitea	4.5 (2.5, 8.0)	<0.0001
Number of metastases	1.1 (1.0, 1.2)	0.0091
Distant failure	2.0 (1.2,3.2)	0.0065
Age (5-year interval)	0.9 (0.8, 0.9)	0.0006
Breast cancer primary sitea	1.6 (1.0, 2.7)	0.05

CI confidence interval, SRS stereotactic radiosurgery

^aEach primary site was compared against all other sites combined

^bIncludes “other and unknown”, gynecologic, and esophagus

^‡No leptomeningeal dissemination observed