Table 2. Univariate and multivariate analysis of prognostic factors for OS.

Factors	Univariate analysis			Multivariate analysis
	HR	95% CI	P	HR	95% CI	P
Age (≥ 60)	0.83	0.41–1.62	0.53
Sex (Male)	0.683	0.39–1.27	0.226
Smoking status (No)	0.52	0.25–0.93	0.037	1.143	0.74–1.72	0.532
KPS (≥ 90)	0.41	0.24–0.70	< 0.01	0.39	0.21–0.68	< 0.01
Tumor location (Distal)	0.63	0.33–1.19	0.14
Tumor length (≤ 5 cm)	0.788	0.49–1.28	0.334
Tumor stage (T1–T3)	0.691	0.48–0.96	0.045	0.663	0.45–0.94	0.031
LN status (No)	0.50	0.24–1.04	0.07
RT dose (≥ 59.4)	0.43	0.25–0.81	0.01	0.40	0.23–0.77	< 0.01