Table 3. Results of multivariate analysis and population characteristics.

Case characteristic	No. of patients	OR	P-value	95% CI
Age
<50 years	4566	1
⩾50 years	13 196	0.63	<0.001	0.51–0.78
Multifocality
No	14 496	1
Yes	2683	1.3	0.024	1.04–1.63
Adjuvant chemotherapy
No	11 302	1
Yes	6459	0.55	<0.001	0.44–0.70
Adjuvant radiotherapy
No	6104	1
Yes	11 657	0.68	<0.001	0.57–0.82
Hormonal therapy
No	10 054	1
Yes	7707	0.54	<0.001	0.43–0.69
Gradation
Low	3748	1
Medium	7450	1.83	<0.001	1.37–2.43
High	5472	2.98	<0.001	2.17–4.10
Tumour size
<2 cm	11 021	1
2–5 cm	6100	1.51	<0.001	1.23–1.84
>5 cm	516	1.63	0.05	1.00–2.67
Triple negative
No	10 905	1
Yes	1888	1.56	0.012	1.1–2.21
ß-0-constant		−2.8

Abbreviations: CI=confidence interval; OR=odds ratio.