Table 3.

Multivariate regression analysis factors influencing non-surgical therapy versus surgery

Parameter	Estimate (β)	OR (95% CI)	Standard error	Z value	p value
SES (per 10% stratum)	0.010	1.01 (1.00–1.02)	0.005	1.877	0.060
Age (years)	− 0.169	0.84 (0.84–0.85)	0.002	− 94.497	< 0.001
Year of treatment	− 0.026	0.97 (0.96–0.99)	0.007	− 3.953	< 0.001
Hospital volume
Small volume	NA	1.00 (reference)	NA	NA	NA
Average volume	0.010	1.01 (0.90–1.13)	0.058	0.172	0.863
Large volume	− 0.101	0.90 (0.82–1.00)	0.053	− 1.916	0.055
Tumor grade
Low grade	NA	1.00 (reference)	NA	NA	NA
Intermediate grade	0.092	1.1 (1.02–1.18)	0.038	2.439	0.015
High grade	0.375	1.45 (1.32–1.60)	0.049	7.700	< 0.001
Histological subtype
Ductal carcinoma	NA	1.00 (reference)	NA	NA	NA
ILC	− 0.031	0.97 (0.89–1.05)	0.043	− 0.723	0.470
Both	0.697	2.01 (1.59–2.53)	0.119	5.859	< 0.001
Mucinous	0.232	1.26 (1.08–1.47)	0.078	2.964	0.003
Medullary	3.040	20.89 (2.92–149.49)	1.004	3.028	0.002
Tubular	0.400	1.49 (0.90–2.47)	0.257	1.556	0.120
Other	0.027	1.03 (0.83–1.27)	0.107	0.254	0.799
Hormone receptor status
Her2 receptor	− 0.136	0.87 (0.78–0.98)	0.057	− 2.376	0.017
Progesterone receptor positive	0.060	1.06 (0.98–1.15)	0.040	1.506	0.132
Estrogen receptor positive	− 0.063	0.94 (0.84–1.05)	0.054	− 1.148	0.251
Triple negative	0.678	1.97 (1.53–2.54)	0.129	5.25	< 0.001
Patient history
No history of disease	NA	1.00 (reference)	NA	NA	NA
Non-oncological history	0.354	1.42 (1.23–1.64)	0.073	4.824	< 0.001
Oncological history	0.086	1.09 (0.72–1.64)	0.21	0.409	0.683
Tumor stage
Stage I tumor	NA	1.00 (reference)	NA	NA	NA
Stage II tumor	− 0.609	0.54 (0.51–0.58)	0.032	− 18.999	< 0.001

OR odds ratio, CI confidence interval, SES socioeconomic status, ILC invasive lobular carcinoma, NA not applicable, NAN not a number