Table 4.

Multivariable analysis of all patients with invasive lobular breast cancer (n = 5135) in the period 2011–2013

Outcome characteristic	MRI use			Primary mastectomy			Margin involvement (more than focal)			Secondary mastectomy			Contralateral breast cancer
	OR	95% CI	P	OR	95% CI	P	OR	95% CI	P	OR	95% CI	P	OR	95% CI	P
MRI
No	N/A	N/A	N/A	1 (Ref)			1 (Ref)						1 (Ref)
Yes				0.86	0.76–0.99	0.030	0.59	0.44–0.79	<.001	0.61	0.61	0.009	2.50	1.73–3.61	<.0001
Year of incidence
2011	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
2012	1.14	0.99–1.32	0.061	1.04	0.89–1.22	0.598	0.93	0.67–1.27	0.632	0.67	0.45–1.02	0.059	1.44	0.96–2.16	0.079
2013	1.30	1.13–1.51	<.001	0.98	0.84–1.15	0.814	0.61	0.43–0.87	0.006	0.57	0.37–0.89	0.012	1.43	0.95–2.16	0.090
Age group (years)
70+	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
<50	4.01	3.31–4.87	<.0001	0.70	0.57–0.86	0.001	1.38	0.87–2.19	0.173	2.14	1.20–3.82	0.010	0.85	0.52–1.38	0.498
50−69	2.71	2.37–3.10	<.0001	0.50	0.43–0.58	<.0001	1.09	0.77–1.54	0.640	1.22	0.78–1.92	0.378	0.65	0.44–0.95	0.025
Clinical tumor size (cT)
cT1	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
cT2	1.83	1.60–2.09	<.0001	3.95	3.43–4.55	<.0001	1.74	1.26–2.40	0.001	2.17	1.44–3.25	<.001	0.35	0.220.56	<.0001
cT3–4	2.69	2.08–3.47	<.0001	31.59	19.12–52.2	<.0001	2.95	0.88–9.87	0.079	7.28	1.85–28.62	0.005	0.45	0.19–1.04	0.063
Unknown	0.53	0.39–0.71	<.0001	2.23	1.67–2.99	<.0001	2.08	1.14–3.80	0.020	1.86	0.89–3.91	0.100	3.22	1.95–5.33	<.0001
Clinical nodal status (cN)
cN0	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
cN1–3	0.77	0.63–0.94	0.001	2.82	2.18–3.65	<.0001	1.15	0.60–2.19	0.670	1.31	0.61–2.79	0.493	0.76	0.38–1.53	0.439
Unknown	0.96	0.57–1.61	0.866	1.58	0.92–2.73	0.099	2.24	0.83–6.01	0.110	4.07	1.25–13.32	0.020	0.85	0.25–2.86	0.792
ER, PR and HER2 status
ER+ or PR+, and HER2−	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
ER+ or PR+, and HER2+	0.75	0.56–1.02	0.067	1.49	1.06–2.09	0.020	0.67	0.28–1.61	0.372	0.87	0.29–2.60	0.804	1.31	0.56–3.05	0.536
ER− and PR− and HER2−	0.52	0.34–0.79	0.002	1.19	0.74–1.92	0.476	1.17	0.43–3.18	0.762	2.50	0.77–8.13	0.127	0.42	0.06–3.09	0.395
ER− and PR− and HER2+	1.35	0.62–2.98	0.451	1.66	0.71–3.92	0.245	0.70	0.08–6.06	0.748	1.51	0.15–15.3	0.727	4.02	0.79–20.35	0.093
Unknown	0.36	0.25–0.53	<.0001	1.70	1.18–2.44	0.004	0.49	0.18–1.39	0.183	0.60	0.17–2.07	0.414	1.98	1.01–3.90	0.047
Tumor grade
1	1 (Ref)			1 (Ref)			1 (Ref)						1 (Ref)
2	0.81	0.69–0.95	0.011	1.33	1.12–1.57	0.001	0.96	0.68–1.37	0.833	0.94	0.61–1.47	0.794	0.70	0.48–1.04	0.077
3	0.60	0.47–0.76	<.0001	1.39	1.06–1.81	0.016	1.55	0.90–2.65	0.113	1.11	0.56–2.22	0.763	0.36	0.15–0.87	0.024
Unknown	0.97	0.72–1.32	0.860	1.15	0.83–1.58	0.400	0.99	0.50–1.94	0.964	0.66	0.27–1.59	0.351	0.83	0.43–1.63	0.597
Multifocality
No	1 (ref)			1 (Ref)			1 (Ref)						1 (Ref)
Yes	1.59	1.38–1.82	<.0001	3.81	3.26–4.45	<.0001	2.39	1.71–3.34	<.0001	6.74	4.50–10.08	<.0001	1.48	1.04–2.09	0.029
Unknown	0.40	0.21–0.76	0.006	0.66	0.37–1.18	0.162	5.00	1.42–17.53	0.012	13.79	2.94–64.6	0.001	1.29	0.36–4.56	0.695
Margin involvement
No										1 (Ref)
Yes	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	34.77	23.84–50.71	<0.0001	N/A	N/A	N/A