Table 3.

Cox regression for predictors of overall survival

Predictors		Univariable P value hazard ratio 95% CI		Multivariable P value hazard ratio 95% CI
Patient age
δ50	Ref.	–	–	Ref.	–	–
51–55	0.105	–	–	0.506	–	–
56–65	< 0.001	2.193	1.864–2.580	< 0.001	1.685	1.343–2.114
> 65	< 0.001	6.625	5.711–7.685	< 0.001	2.994	2.367–3.788
Female gender	< 0.001	0.726	0.658–0.800	< 0.001	0.759	0.667–0.863
Patient race
White	Ref.	–	–	Ref.	–	–
Black	0.002	1.177	1.060–1.307	0.149	–	–
American Indian	0.657	–	–	0.085	–	–
Asian/Pacific Islander	< 0.001	0.468	0.355–0.617	0.002	0.566	0.395–0.810
Other/unknown	0.407	–	–	0.556	–	–
Patient insurance
Private	Ref.	–	–	Ref.	–	–
Government	< 0.001	4.195	3.779–4.657	< 0.001	1.926	1.625–2.283
None	< 0.001	2.636	2.045–3.397	< 0.001	2.620	1.890–3.633
Unknown status	< 0.001	2.121	1.514–2.971	0.043	1.608	1.016–2.547
Treatment at an academic center	0.192	–	–	0.308	–	–
Charlson/Deyo comorbidity score
0	Ref.	–	–	Ref.	–	–
1	< 0.001	2.202	1.941–2.498	< 0.001	1.565	1.329–1.843
2	< 0.001	4.281	3.495–5.243	< 0.001	2.950	2.274–3.828
ε3	< 0.001	7.725	5.892–10.129	< 0.001	4.881	3.434–6.937
Tumor grade
Well-differentiated	Ref.	–	–	Ref.	–	–
Moderately differentiated	< 0.001	1.724	1.311–2.267	0.042	1.408	1.012–1.961
Poorly differentiated	< 0.001	21.480	18.097–25.495	< 0.001	4.877	3.749–6.344
Grade unknown	0.010	1.194	1.043–1.366	0.322	–	–
Tumor size
≤ 10 mm	Ref.	–	–	Ref.	–	–
11–20 mm	< 0.001	2.584	2.157–3.096	< 0.001	2.081	1.721–2.515
> 20 mm	< 0.001	5.168	4.511–5.922	< 0.001	2.099	1.753–2.513
Positive lymph nodes	< 0.001	6.290	5.372–7.366	< 0.001	2.419	1.856–3.151
Positive resection margins	< 0.001	1.332	1.139–1.558	0.014	1.275	1.051–1.547
Treatment
Local excision	Ref.	–	–	Ref.	–	–
Radical resection	< 0.001	3.105	2.712–3.554	0.683	–	–
Observation alone	< 0.001	3.484	3.103–3.912	< 0.001	2.750	2.296–3.293