Relationship between Clinicopathologic Variables in Breast Cancer Overall Survival Using Biogeography-Based Optimization Algorithm

Table 3

Multivariate Cox regression analysis of clinicopathologic variables in breast cancer overall survival.

Variable	Comparison		Fully adjusted		Stepwise selected						BBO selected
					Model 1^1		Model 2^2		Model 3^3
C-statistic			76%		78%		78%		77%		80%
p-value			<0.001		<0.001		<0.001		<0.001		<0.001
			HR	p-value	HR	p-value	HR	p-value	HR	p-value	HR	p-value
Age	50 years	50 years	0.515	0.015			0.589	0.036	0.523	0.003
Grade	III	I, II	1.524	0.132			1.830	0.026	1.642	0.073
Her 2	Positive	Negative	0.103	0.103
Estrogen receptor	Positive	Negative	0.506	0.195					0.451	0.003
Progesterone receptor	Positive	Negative	0.801	0.595
Tumor size (AJCC stage)	2.4 cm	2.4 cm	2.430	0.005	3.017	<0.001	2.435	0.004	2.436	0.004	2.372	0.006
Lymph node (AJCC stage)	Positive	Negative	1.511	0.103							1.301	0.038
Lymphovascular invasion	Positive	Negative	1.776	0.046	1.878	0.016	1.642	0.068	1.753	0.038	1.606	0.096
Dermal invasion	Positive	Negative	1.549	0.298	2.152	0.048			1.722	0.188	1.548	0.028
Perineural invasion	Yes	No	1.745	0.081			1.994	0.028	1.827	0.060	1.546	0.168
Surgery method	Total mastectomy	Partial mastectomy	1.735	0.087			1.869	0.031	1.848	0.066	1.633	0.092
Radiotherapy	Without RT	With RT	1.299	0.378
Chemotherapy	Without CT	With CT	1.338	0.379							1.234	0.491
Hormone therapy	Without HT	With HT	1.022	0.962	2.231	0.002	1.918	0.014			2.178	0.003
Target therapy	Without TT	With TT	0.859	0.697

Stepwise selection met the p = 0.05 level for entry into the model; ² Stepwise selection met the p = 0.1 level for entry into the model; ³ Stepwise selection met the p = 0.2 level for entry into the model.
p-value is estimated using Cox PH regression.
HR: hazard ratio; HER2: human epidermal growth factor receptor 2.