Table 2.

Cox regression analyses of prognostic factors affecting T1a glottic cancer patient survival in the training cohort.

	Overall survival				Cancer-specific survival
	Univariate analysis		Multivariate analysis		Univariate analysis		Multivariate analysis
Variable	HR(95%CI)	P	HR(95%CI)	P	HR(95%CI)	P	HR(95%CI)	P
Age, years
<65	Reference		Reference		Reference
≥65	1.67 (1.23–2.28)	.001	1.73 (1.27–2.37)	.001	1.00 (0.66–1.51)	1
Sex
Female	Reference				Reference
Male	0.89 (0.58–1.38)	.60			1.30 (0.63–2.68)	.48
Race
Black	Reference		Reference		Reference
White	0.75 (0.49–1.17)	.20	0.83 (0.53–1.29)	.40	0.86 (0.44–1.65)	.64
Other (American Indian/AK Native, Asian/Pacific Islander)	0.21 (0.05–0.91)	.04	0.27 (0.06–1.16)	.08	0.24 (0.03–1.90)	.18
Marital status
Unmarried	Reference		Reference		Reference
Married	0.62 (0.47–0.83)	.001	0.65 (0.49–0.87)	.003	0.68 (0.45–1.02)	.06
Grade
Grade I&II	Reference				Reference		Reference
Grade III&IV	1.25 (0.80–1.94)	.33			2.15 (1.27–3.63)	.004	2.07 (1.22–3.51)	.007
Stage (AJCC, 7th edition, 2010)
I&II	Reference		Reference		Reference		Reference
III&IV	5.19 (2.29–11.74)	<.001	3.47 (1.48–8.15)	.004	8.53 (3.45–21.12)	<.001	6.09 (2.31–16.09)	<.001
N
N0	Reference		Reference		Reference		Reference
N1&N2	5.19 (2.29–11.74)	<.001	NA∗		8.53 (3.45–21.12)	<.001	NA∗
M
M0	NA†				NA†
Primary site surgery
No	Reference		Reference		Reference		Reference
Yes	0.68 (0.51–0.90)	.007	0.77 (0.57–1.05)	.10	0.61 (0.41–0.92)	.02	0.61 (0.41–0.93)	.02
Radiation
No/Unknown	Reference		Reference		Reference
Yes	1.62 (1.14–2.30)	.007	1.31 (0.90–1.90)	.16	1.33 (0.83–2.15)	.24
Chemotherapy
No/Unknown	Reference		Reference		Reference		Reference
Yes	3.55 (1.75–7.22)	<.001	3.12 (1.49–6.56)	.003	5.51 (2.40–12.61)	<.001	3.35 (1.37–8.21)	.008
Year of diagnosis
2010–2012	Reference				Reference
2013–2015	0.79 (0.56–1.13)	.20			0.96 (0.59–1.54)	.85