Table 4. Prognostic prediction by Kapplan–Meier survival analyses.

Factors	3–year OS (%)	5–year OS (%)	MS (months)	AIC	C–index	Log rank χ2 value	P
N stage				898.7	0.687	151.1	< 0.001
N0	85.2	72.5	124.1 (7.5–176.0)
N1	76.1	63.4	113.0 (3.5–174.0)
N2	67.1	52.8	99.5 (1.4–172.4)
N3a	42.3	27.5	29.9 (0.9–160.0)
N3b	26.5	20.4	23.0 (0.3–172.7)
Nr stage				880.1	0.696	156.7	< 0.001
Nr0	85.2	72.5	124.1 (7.5–176.0)
Nr1	78.3	63.4	106.0 (1.4–160.0)
Nr2	58.4	46.9	54.9 (0.3–174.0)
Nr3	30.4	22.6	26.1 (0.9–172.7)
TNM stage				872.3	0.754	161.7	< 0.001
IA	92.6	82.5	134.2 (9.3–156.2)
IB	87.3	77.2	121.2 (1.4–172.4)
IIA	81.1	71.6	101.3 (0.3–174.0)
IIB	79.8	60.6	92.7 (4.0–176.0)
IIIA	66,2	55.4	82.6 (5.4–157.2)
IIIB	55.9	46.2	46.6 (0.9–150.3)
IIIC	33.1	22.2	25.4 (0.8–172.7)
TNrM stage				850.4	0.799	182.3	< 0.001
IA	92.6	82.5	134.2 (9.3–165.2)
IB	90.4	80.8	112.5 (6.5–176.0)
IIA	85.0	73.4	98.4 (1.4–160.9)
IIB	79.5	61.8	84.6 (0.3–173.1)
IIIA	64.3	57.0	65.4 (0.8–161.8)
IIIB	56.4	41.3	47.3 (0.9–175.6)
IIIC	30.2	22.4	24.0 (0.6–172.3)

OS: overall survival ; MS: median survival time; AIC: Akaike Information Criterion value; C–index: concordance index.