Fractionated Stereotactic Radiation Therapy Using Volumetric Modulated Arc Therapy in Patients with Solitary Brain Metastases

Table 2

Univariate and multivariate Cox analysis of covariates related to local failure.

Variables	Univariate	value	Multivariate	value
	Hazard ratio (95% CI)		Hazard ratio (95% CI)
Gender (male vs. female)	0.31 (0.034-2.75)	0.291	—	—
Age (18-59 years vs. ≥60 years)	0.76 (0.13-4.55)	0.762	—	—
Histology (NSCLC vs. breast)	0.39 (0.07-2.33)	0.301	—	—
Histology (NSCLC vs. others)	0.00 (0.00-+inf)	0.998	—	—
Tumor diameter (cm)	3.97 (1.38-11.43)	0.011	—	—
Fraction dose (Gy)	0.16 (0.047-0.54)	0.003	0.14 (0.019-0.95)	0.046
PTV margin (0 vs. 1 mm)	7.09 (0.78-64.53)	0.082	—	—

NSCLC: non-small-cell lung cancer; CI: confidence interval; PTV: planning target volume.