Table 1

Multivariable Cox proportional hazards regression models for overall survival, in the entire group and stratified by lymph node status

Variable	Level	Overall		pN0		pN1/2
Variable	Level	Multivariable hazard ratio (95% CI)*	P value	Multivariable hazard ratio (95% CI)*	P value	Multivariable hazard ratio (95% CI)*	P value
LN surgery	LND only	1.0 reference		1.0 reference		1.0 reference
LN surgery	SLN-B only	0.92 (0.73 to 1.17)	0.494	0.95 (0.73 to 1.24)	0.692	0.91 (0.54 to 1.52)	0.710
Age	SLN-B/LND	0.91 (0.77 to 1.08)	0.271	1.04 (0.85 to 1.27)	0.706	0.77 (0.57 to 1.04)	0.084
Age	Per 10 years	1.61 (1.56 to 1.67)	<0.001	1.70 (1.64 to 1.77)	<0.001	1.38 (1.30 to 1.47)	<0.001
Race	White	1.0 reference		1.0 reference		1.0 reference
	Black	1.45 (1.36 to 1.56)	<0.001	1.52 (1.40 to 1.66)	<0.001	1.33 (1.19 to 1.49)	<0.001
	Other	0.94 (0.83 to 1.07)	0.368	0.93 (0.79 to 1.10)	0.415	0.92 (0.74 to 1.15)	0.467
	Unknown	0.97 (0.75 to 1.25)	0.821	0.91 (0.66 to 1.27)	0.583	1.07 (0.72 to 1.60)	0.733
Charlson-Deyo score	0	1.0 reference		1.0 reference		1.0 reference
	1	1.21 (1.14 to 1.28)	<0.001	1.28 (1.20 to 1.37)	<0.001	1.09 (0.99 to 1.21)	0.096
	≥2	1.66 (1.52 to 1.82)	<0.001	1.90 (1.71 to 2.11)	<0.001	1.25 (1.06 to 1.49)	0.010
Insurance status	Private insurance	1.0 reference		1.0 reference		1.0 reference
	Not insured	1.31 (1.14 to 1.52)	<0.001	1.26 (1.04 to 1.52)	0.019	1.29 (1.03 to 1.62)	0.028
	Medicaid	1.24 (1.10 to 1.39)	<0.001	1.23 (1.06 to 1.43)	0.008	1.13 (0.93 to 1.38)	0.211
	Medicare	1.13 (1.06 to 1.20)	<0.001	1.14 (1.06 to 1.23)	<0.001	1.10 (0.98 to 1.23)	0.109
	Other government	1.0 (0.76 to 1.30)	0.984	0.95 (0.67 to 1.35)	0.782	1.12 (0.74 to 1.71)	0.584
	Unknown	1.19 (0.94 to 1.51)	0.153	1.14 (0.84 to 1.55)	0.400	1.21 (0.82 to 1.78)	0.334
Income	≥$63 333	1.0 reference		1.0 reference		1.0 reference
	$50 354–63 332	1.04 (0.97 to 1.12)	0.231	1.10 (1.01 to 1.19)	0.030	0.96 (0.85 to 1.09)	0.531
	$40 227–50 353	1.05 (0.97 to 1.14)	0.200	1.11 (1.01 to 1.22)	0.031	0.94 (0.82 to 1.08)	0.387
	<$40 227	1.11 (1.01 to 1.21)	0.025	1.17 (1.05 to 1.30)	0.006	1.01 (0.87 to 1.18)	0.859
	Unknown	0.54 (0.28 to 1.04)	0.065	0.56 (0.21 to 1.51)	0.253	0.56 (0.23 to 1.35)	0.194
Education (% no HSD)	≥17.6%	1.05 (0.95 to 1.15)	0.326	1.01 (0.90 to 1.14)	0.816	1.07 (0.90 to 1.26)	0.441
	10.9%–17.5%	1.07 (0.99 to 1.16)	0.104	1.04 (0.94 to 1.15)	0.451	1.09 (0.94 to 1.26)	0.261
	6.3%–10.8%	1.14 (1.06 to 1.22)	<0.001	1.13 (1.04 to 1.23)	0.006	1.13 (0.99 to 1.28)	0.074
	<6.3%	1.0 reference		1.0 reference		1.0 reference
	Unknown	2.10 (1.05 to 4.21)	0.037	2.25 (0.81 to 6.25)	0.122	1.74 (0.65 to 4.65)	0.270
Facility type	Community	1.24 (1.09 to 1.42)	0.001	1.29 (1.10 to 1.53)	0.002	1.13 (0.90 to 1.41)	0.287
	Comprehensive community	1.13 (1.07 to 1.19)	<0.001	1.16 (1.08 to 1.23)	<0.001	1.07 (0.98 to 1.18)	0.150
	Academic	1.0 reference		1.0 reference		1.0 reference
	Integrated network	1.08 (1.00 to 1.16)	0.040	1.13 (1.03 to 1.23)	0.007	1.0 (0.88 to 1.14)	0.968
	Unknown	2.42 (1.84 to 3.18)	<0.001	2.55 (1.81 to 3.59)	<0.001	1.99 (1.27 to 3.14)	0.003
AJCC pathological N stage	pN0	1.0 reference		–		–
	pN1	1.65 (1.53 to 1.77)	<0.001	–		1.0 reference
	pN2	1.73 (1.59 to 1.89)	<0.001	–		1.06 (0.97 to 1.15)	0.241
AJCC pathological T stage	pT1	1.18 (0.88 to 1.58)	0.263	1.07 (0.77 to 1.49)	0.691	1.78 (0.97 to 3.27)	0.063
	pT1A	1.0 reference		1.0 reference		1.0 reference
	pT1B	1.69 (1.58 to 1.80)	<0.001	1.65 (1.53 to 1.78)	<0.001	1.43 (1.21 to 1.68)	<0.001
	pT2	2.30 (2.12 to 2.49)	<0.001	2.13 (1.93 to 2.35)	<0.001	2.10 (1.78 to 2.47)	<0.001
	pT3/3A/3B	3.21 (2.97 to 3.47)	<0.001	3.06 (2.77 to 3.39)	<0.001	2.91 (2.50 to 3.39)	<0.001
Grade	Well/moderately	1.0 reference		1.0 reference		1.0 reference
	Poorly/undifferentiated	2.08 (1.94 to 2.22)	<0.001	2.03 (1.87 to 2.19)	<0.001	2.10 (1.84 to 2.40)	<0.001
	Unknown	1.55 (1.45 to 1.66)	<0.001	1.44 (1.33 to 1.56)	<0.001	1.81 (1.57 to 2.08)	<0.001
Lymph vascular invasion	Not present	1.0 reference		1.0 reference		1.0 reference
	Present	1.63 (1.54 to 1.73)	<0.001	1.71 (1.60 to 1.83)	<0.001	1.33 (1.19 to 1.49)	<0.001
	Unknown	1.15 (1.04 to 1.28)	0.009	1.13 (1.0 to 1.27)	0.055	1.04 (0.85 to 1.28)	0.713
Histotype	1	1.0 reference		1.0 reference		1.0 reference
Histotype	2	1.63 (1.54 to 1.73)	<0.001	1.71 (1.59 to 1.84)	<0.001	1.44 (1.31 to 1.60)	<0.001
Adjuvant chemotherapy	No chemotherapy received	1.0 reference		1.0 reference		1.0 reference
Adjuvant chemotherapy	Chemotherapy received	0.81 (0.76 to 0.86)	<0.001	0.85 (0.79 to 0.92)	<0.001	0.68 (0.61 to 0.75)	<0.001
Adjuvant hormone therapy	No hormone therapy received	1.0 reference		1.0 reference		1.0 reference
	Hormone therapy received	1.12 (0.84 to 1.49)	0.442	1.01 (0.66 to 1.53)	0.974	1.09 (0.74 to 1.63)	0.658
	Unknown	1.07 (0.91 to 1.25)	0.441	1.12 (0.93 to 1.36)	0.240	1.0 (0.75 to 1.33)	0.997
Adjuvant radiation therapy	No radiation	1.0 reference		1.0 reference		1.0 reference
	Brachytherapy	0.81 (0.75 to 0.86)	<0.001	0.85 (0.79 to 0.92)	<0.001	0.63 (0.53 to 0.74)	<0.001
	External beam	0.88 (0.83 to 0.94)	<0.001	1.01 (0.92 to 1.10)	0.876	0.73 (0.67 to 0.81)	<0.001
	Other	0.81 (0.57 to 1.14)	0.224	0.90 (0.58 to 1.40)	0.643	0.68 (0.38 to 1.20	0.181

*Hazard ratios estimate the risk of an event (death for any cause) in each group compared with that of the reference group. Hazard ratios lower than one represent a risk of events lower than the reference group, whereas hazard ratios higher than one represent a higher risk of events.
AJCC, American Joint Committee on Cancer; HSD, high-school diploma; LN, lymph node; LND, lymphadenectomy; SLN-B, sentinel lymph node biopsy.