Table 2.

Univariate and multivariate analyses of overall survival in the training set

Variables	Univariate analysis	Multivariate analysis
	P‐value	HR (95% CI)	P‐value
Age (years)	<.001		.288
˂40		Reference
40‐49		1.111 (0.795, 1.554)	.537
50‐59		1.082 (0.793, 1.476)	.620
60‐75		1.088 (0.796, 1.489)	.596
>75		1.423 (0.991, 2.042)	.056
Race	<.001		<.001
White		Reference
Black		1.586 (1.285, 1.957)	<.001
Othera		0.962 (0.655, 1.413)	.843
Marital status	<.001		.011
Married		Reference
Unmarried		1.235 (1.049, 1.454)
Grade	.021		.258
Grade I/II		Reference
Grade III/IV		1.091 (0.881, 1.350)
Unknown		0.914 (0.709, 1.179)
N stage	.047		.002
N0		Reference
N1		0.993 (0.779, 1.265)	.954
N2		1.213 (0.909, 1.618)	.190
N3		1.460 (1.122, 1.901)	.005
M stage	<.001		<.001
M0		Reference
M1		2.248 (1.850, 2.733)
Tumor extensionb	.087		.140
<50%		Reference
≥50%		1.215 (0.999, 1.479)	.052
Unknown		1.016 (0.731, 1.412)	.923
HoR	<.001		<.001
Negative		Reference
Positive		0.521 (0.437, 0.621)	<.001
Unknown		1.048 (0.764, 1.438)	.771
HER, 2	.001		.001
Negative		Reference
Positive		0.425 (0.274, 0.661)	<.001
Unknown		0.810 (0.636, 1.030)	.085
Surgery	<.001		<.001
No surgery		Reference
Partial mastectomy		0.613 (0.407, 0.922)	.019
Simple mastectomy		0.532 (0.386, 0.733)	<.001
Radical mastectomy		0.592 (0.472, 0.743)	<.001
Chemotherapy	<.001		<.001
No/unknown		Reference
Yes		0.464 (0.370, 0.583)
Radiotherapy	<.001		.010
No/unknown		Reference
Yes		0.794 (0.666, 0.946)

Abbreviation: HoR, hormone receptor.

^aOther includes American Indian/Alaska native, Asian/Pacific Islander.

^bTumor extension means the percentage of the area of tumors in the unilateral breast.