Table 3. Uni- and multivariate analysis of the training cohort for CSS.

Variable	Univariate analysis				Multivariate analysis
	HR	95% CI	P		HR	95% CI	P
Age (year)			0.000				0.000
40–59	Reference				Reference
60–79	1.431	1.153–1.775	0.001		1.630	1.310–2.028	0.000
≥80	2.255	1.793–2.836	0.000		2.754	2.172–3.494	0.000
Sex			0.000				0.268
Male	Reference				Reference
Female	1.286	1.129–1.464	0.000		1.080	0.943–1.236	0.268
Laterality			0.623
Left	Reference
Right	1.033	0.908–1.176	0.623
Race			0.051				0.724
White	Reference				Reference
Black	1.282	0.966–1.703	0.085		1.084	0.811–1.448	0.586
Other	1.223	0.990–1.511	0.062		1.072	0.865–1.328	0.527
T stage			0.000				0.000
T1	Reference				Reference
T2	1.366	1.072–1.740	0.012		1.516	1.188–1.936	0.001
T3	2.416	2.023–2.885	0.000		2.330	1.944–2.792	0.000
T4	7.392	6.034–9.056	0.000		4.503	3.623–5.597	0.000
N stage			0.000				0.000
N0	Reference				Reference
≥N1	3.846	3.347–4.420	0.000		1.737	1.469–2.054	0.000
M stage			0.000				0.000
M0	Reference				Reference
M1	7.130	6.091–8.346	0.000		2.556	2.090–3.125	0.000
Surgery			0.000				0.000
No	Reference				Reference
Yes	0.199	0.170–0.234	0.000		0.383	0.316–0.463	0.000
LNR			0.486
No	Reference
Yes	1.052	0.912–1.215	0.486
Radiation			0.000				0.017
No/Unknown	Reference				Reference
Yes	2.332	1.887–2.883	0.000		1.300	1.047–1.614	0.017
Marital status			0.001				0.616
Married	Reference				Reference
Previously married	1.320	1.144–1.523	0.000		1.074	0.922–1.251	0.360
Never married	1.127	0.902–1.409	0.292		1.067	0.850–1.339	0.576
Insurance status			0.940
Any medicaid	Reference				Reference
Insured	1.306	0.821–1.307	0.766
Uninsured	0.980	0.545–1.763	0.946

CSS, cancer-specific survival; HR, hazard ratio; CI, confidence interval; LNR, lymph node removal.