Table 4. Multivariate analysis on overall survival (Cox regression model).

Factors	Relative risk (RR)	95% CI	P-value
N statusa	1.368	1.080–1.733	0.009
Stageb	1.433	1.123–1.829	0.004
Differentiationc	0.608	0.494–0.747	<0.001
Rad51d	1.926	1.435–2.585	<0.001

^aN₃ vs N₂ vs N₁ vs N₀.

^bI vs II vs III vs IV.

^cPoor vs moderate vs well.

^dHigh-level expression vs low-level expression.