Table 3. Cox regression analysis for overall survival.

Variables	Univariate analysis				Multivariate analysis
	Hazard ratio	95% CI	P value		Hazard ratio	95% CI	P value
Age	1.018	0.993–1.044	0.162		1.020	0.993–1.048	0.142
Tumor size	2.496	1.530–4.072	<0.001		1.841	1.102–3.074	0.020
Lymph node metastasis	2.209	1.622–3.010	<0.001		2.044	1.481–2.822	<0.001
ER expression	0.787	0.471–1.312	0.357		0.802	0.391–1.637	0.544
PR expression	0.747	0.449–1.242	0.259		0.863	0.429–1.734	0.678
HER2 expression	0.826	0.495–1.377	0.462		0.764	0.446–1.309	0.327
BMI	0.972	0.897–1.053	0.484		0.948	0.871–1.031	0.214

BMI, body mass index; ER, estrogen receptor; PR, progesterone receptor; HER2, human epidermal growth factor receptor-2.