Table 3. Multivariate analysis using the stepwise backward elimination method in patients with IDC.

Variable	Partial regressioncoefficient	Wald value	HR	95%CI	P-value
Age	−0.054	0.016	0.947	0.407–2.205	0.900
Tumor size	0.540	1.339	1.716	0.688–4.282	0.247
Lymph node involvement	2.388	16.081	10.892	3.390–34.996	<0.001
ER Status	−0.979	1.926	0.376	0.094–1.497	0.165
PR Status	−0.300	0.189	0.741	0.192–2.861	0.664
HER2 Status	0.673	1.385	1.960	0.639–6.014	0.239
MMP9 expression	−0.422	0.747	0.656	0.252–1.707	0.387
MDM2 expression	1.582	8.065	4.864	1.633–14.490	0.005

HR: hazard ratio; 95%CI: 95% confidence interval; ER: estrogen receptor; PR: progesterone receptor; HER2: human epidermal growth factor receptor 2.