TABLE 1.

Clinical variables of the 287 HNSCC patients with RT.

Variable	Subgroup	Total		Training set		Test set		P*
		N	%	N	%	N	%
Age (year)	≤60	156	54.36	87	58.39	69	50.0	0.22
	>60	131	45.64	62	41.61	69	50.0
Gender	Male	224	78.05	123	82.55	101	73.19	0.15
	Female	63	21.95	26	17.45	37	26.81
T stage	1	14	4.88	9	6.04	5	3.62	0.34
	2	66	22.30	27	18.12	39	28.26
	3	79	27.53	45	30.20	34	24.64
	4	122	42.51	63	42.28	59	42.75
N stage	0	113	39.37	57	38.26	56	40.58	0.35
	1	56	19.51	26	17.45	30	21.74
	2	105	36.59	59	39.60	46	33.33
	3	3	1.05	0	0	3	2.26
Clinical stage	1	9	3.14	2	1.34	7	5.07	0.30
	2	23	8.01	12	8.05	11	7.97
	3	48	16.72	21	14.09	27	19.57
	4	207	72.13	114	76.51	93	67.39
Tumor grade	1	25	8.71	11	7.38	14	10.14	0.20
	2	168	58.54	82	55.03	86	62.32
	3	75	26.13	47	31.54	28	20.29
	4	2	0.70	2	1.34	0	0
Survival time (month)		21.77		20.73		23.62		0.32
Vital status	Death	110	38.33	57	38.26	53	38.41	0.12
	Alive	177	61.67	92	61.74	85	61.59

* The difference between the test set and training set was calculated in terms of clinical pathologic factors. Specifically, age was compared with Wilcoxon rank-sum test; gender, clinical T, N, stage, and grade were compared with the chi-squared test; survival time and the status difference were assessed with the log-rank test.