Table 2. Univariate and multivariate Cox proportional hazards regression for DMFS.

Variable	Univariate analysis				Multivariate analysis
	HR	95% CI	P		HR	95% CI	P
Age at diagnosis (years)
≤35	2.74	1.22–6.20	0.015		2.81	1.24–6.38	0.014
35–50	1				1
>50	0.94	0.50–1.77	0.860		1.43	0.61–3.33	0.411
Tumor size (cm)
≤2	1				1
>2	2.46	1.39–4.36	0.002		2.08	1.17–3.72	0.013
Lymph node status
Negative	1				1
Positive	3.02	1.70–5.36	<0.001		2.81	1.56–5.05	0.001
LVI status
Negative	1				1
Positive	2.04	1.03–4.03	0.039		1.61	0.80–3.25	0.185
Molecular subtype
Luminal A	1				1
Luminal B (HER2–)	1.64	0.69–3.91	0.264		1.81	0.55–5.95	0.329
Luminal B (HER2+)	1.81	0.74–4.42	0.195		1.83	0.67–5.01	0.238
HER2-enriched	3.84	1.33–11.07	0.013		4.34	1.36–13.80	0.013
Triple negative	3.31	1.20–9.13	0.021		3.85	1.19–12.48	0.025

DMFS, distant metastasis-free survival; HR, hazard ratio; CI, confidence interval; LVI, lymphovascular invasion; HER2, human epidermal growth factor receptor 2.