Table I.

Distribution of selected characteristics of a SCCHN patient cohort (n = 1376)

Variable	Total		SPM free		SPM		P-valuesa
	N	%	n	%	n	%
Total patients	1376	100	1266	92.0	110	8.0
Age	57.3 ± 11.3		57.0 ± 11.5		60.8 ± 7.9		<0.010
≤ median (57 years)	722	52.5	686	54.2	36	32.7	<0.001
> median (57 years)	654	47.5	580	45.8	74	67.3
Sex							0.734
Male	1045	75.9	960	75.8	85	77.3
Female	331	24.1	306	24.2	25	22.7
Ethnicity							0.090
Non-Hispanic white	1154	83.9	1068	84.4	86	78.2
Other	222	16.1	198	15.6	24	21.8
Smoking							0.022
Never	379	27.5	359	28.4	20	18.2
Ever	997	72.5	907	71.6	90	81.8
Alcohol							0.050
Never	369	26.8	349	27.6	21	19.1
Ever	1007	73.2	917	72.4	89	80.9
Index cancer site							0.118
Oral cavity	452	32.9	418	33.0	34	30.9
Oropharynx	618	44.9	575	45.4	43	39.1
Larynx/hypopharynx	306	22.2	273	21.6	33	30.0
Index cancer stage							0.830
1 or 2	351	25.5	322	25.4	29	26.4
3 or 4	1025	74.5	944	74.6	81	73.6
Treatment							0.982
Surgery	247	17.9	228	18.0	19	17.3
Surgery + adjuvant Txb	341	24.8	312	24.6	29	26.4
XRTc	346	25.2	319	25.2	27	24.5
XRT + chemotherapy	442	32.1	407	32.2	35	31.8

^aP-values were calculated from the chi-square test.

^bAdjuvant Tx: adjuvant radiotherapy and/or chemotherapy.

^cXRT: radiotherapy.