Table 3. Multivariate subgroup analyses for OS from SRT in NSCLC.

Parameters	HR	95% CI	p values
Interval time (< 13.63 months vs. ≥ 13.63 months)	0.256	0.083-0.791	0.018
PTV volume (< 15.33 mL vs. ≥ 15.33 mL)	3.656	1.348-9.913	0.011
CT after SRT (yes vs. no)	1.549	0.559-4.008	0.367

Abbreviations: OS: overall survival; NSCLC: non-small cell lung cancer; HR: hazard ratio; CI: confidence interval; SRT: stereotactic radiation therapy; PTV: planning target volume; CT: chemotherapy.