Table 3.

Univariate and multivariate analysis of CSS for the matched cohort after PSM.

Characteristic	Univariate			Multivariate
	P-value	OR	95% CI	P-value	OR	95% CI
Year of diagnosis	0.903
2004–2007	1
2009–2011	0.838	0.952	0.592–1.530
2012–2015	0.651	0.875	0.490–1.562
Gender
Male	1			1
Female	0.056	0.491	0.237–1.018	0.148	0.574	0.270–1.219
Age groups (years)	0.554
≤50	1
51–60	0.617	1.223	0.556–2.694
61–70	0.657	1.188	0.555–2.546
≥71	0.215	1.715	0.732–4.021
Race
White	1
Black and others	0.177	0.537	0.218–1.325
cT classification	0.001			0.002
T1	1			1
T2	0.650	0.807	0.320–2.034	0.454	0.697	0.270–1.797
T3	0.034	2.127	1.058–4.276	0.083	1.880	0.921–3.838
T4	0.002	5.201	1.843–14.676	0.009	4.107	1.420–11.875
Tx	0.647	0.617	0.078–4.874	0.423	0.424	0.052–3.455
cN classification	0.001			0.004
N0	1			1
N1	0.176	1.407	0.857–2.310	0.269	1.330	0.802–2.206
N2	0.003	2.285	1.318–3.962	0.010	2.116	1.195–3.748
N3	< 0.001	4.859	2.003–11.789	0.002	4.134	1.688–10.127
Tumor histology
Adenocarcinoma	1			1
SCC	0.031	0.428	0.198–0.926	0.129	0.538	0.242–1.198
Histological grade	0.410
Well	1
Moderate	0.380	1.902	0.453–7.989
Poor/Undifferentiated	0.406	1.821	0.443–7.487
Unknown	0.156	3.037	0.655–14.071
PORT
Yes	1
No	0.494	1.164	0.754–1.797

T, tumor; N, nodal; SCC, squamous cell carcinoma; PORT, postoperative radiotherapy.