Table 1.

Clinical covariates for the 307 HNSCC RT patients

		Total	%	Training set	%	Validation set	%	P
Age, years, n (%)	≤60	152	49.5	109	70.8	94	61.4	0.119
	>60	155	50.5	46	29.9	59	38.6
Gender, n (%)	Male	240	78.2	128	83.1	112	73.2	0.039a
	Female	67	21.8	26	16.9	41	26.8
Clinical T, n (%)	1	16	5.2	9	5.8	7	4.6	0.258
	2	71	23.1	38	24.7	33	21.6
	3	84	27.4	48	31.2	36	23.5
	4	127	41.4	56	36.4	71	46.4
Clinical N, n (%)	0	112	36.5	54	35.1	58	37.9	0.763
	1	58	18.9	31	20.1	27	17.6
	2	120	39.1	62	40.3	58	37.9
	3	5	1.6	3	1.9	2	1.3
Clinical M, n (%)	0	288	93.8	144	93.5	144	94.1	0.247
	1	3	1.0	3	1.9	0	0.0
Clinical stage, n (%)	I	7	2.3	4	2.6	3	2.0	0.396
	II	33	10.7	17	11.0	16	10.5
	III	55	17.9	33	21.4	22	14.4
	IV	204	66.4	96	62.3	107	69.9
Tumor grade, n (%)	1	26	8.5	11	7.1	15	9.8	0.518
	2	178	58.0	84	54.5	94	61.4
	3	79	25.7	41	26.6	38	24.8
	4	7	2.3	5	3.2	2	1.3
Survival time, month (mean ± SD)		23.68	16.3	37.05	22.5	20.3	6.9	0.351
Vital status, n (%)	Death	190	61.9	87	56.5	103	67.3	0.06
	Alive	117	38.1	67	43.5	50	32.7

HNSCC, head and neck squamous carcinoma; RT, radiotherapy. P‐value was from chi‐square test.

^a P < 0.05.