Table 5. Risk factors affecting recurrence-free and overall survival.

	Recurrence-free survival
Variable	Univariate analysis			Multivariate analysis*
	HR	95% CI	p-value	HR	95% CI	p-value
PD-L1 immunoreactivity (positive vs. negative)	3.125	1.448 - 6.745	0.0037	3.029	1.228 - 7.471	0.0018
Lymph node involvement (present vs. absent)	3.076	1.546 - 6.119	0.0014	3.012	1.508 - 6.018	0.016
	Overall survival
Variable	Univariate analysis			Multivariate analysis*
	HR	95% CI	p-value	HR	95% CI	p-value
PD-L1 immunoreactivity (positive vs. negative)	2.222	0.928 - 5.32	0.07
Lymph node involvement (present vs. absent)	5.038	2.28 - 11.13	0.00006

CI, confidence interval; HR, Hazard ratio.

^*Only variables significantly associated in the univariate analysis were included in the multivariate analysis.