Table 1.

Clinical characteristics of training and testing sets.

Clinical characteristics		Training set (n=435) n(%)	Testing set (n=556) n(%)	Chi-square	P value
Gender	male	233(53.6)	306(55.0)	0.213	0.653
	female	202(46.4)	250(45.0)
Age	<65	171(39.3)	210(37.8)	0.245	0.645
	≥65	264(60.7)	346(62.2)
TNM stage	1–2	239(55.0)	295(53.1)	1.063	0.332
	3–4	185(42.5)	261(46.9)
	NA	11(2.5)	0(0.0)