Table 3. Association between SLN metastases and clinicopathologic factors by univariate and multivariate analysis.

			Univariate			Multivariate
	N	% SLN positive	Odds ratio	95% CI	P-value	Odds ratio	95% CI	P-value
Age (years)			0.98	0.98–0.99	0.002	0.98	0.97–0.99	<0.0001
Tumour size (mm)			1.07	1.06–1.09	<0.0001	1.06	1.05–1.08	<0.0001
Histology					<0.0001			0.0004
Ductal	1230	33	1.00			1.00
Ducto-lobular	163	49	1.97	1.42–2.74	<0.0001	2.16	1.48–3.16	0.0001
Lobular	235	39	1.29	0.97–1.72	0.081	1.12	0.82–1.54	0.487
Others	262	25	0.68	0.51–0.93	0.016	0.82	0.58–1.16	0.246
Grading					<0.0001			0.0003
I	293	18	0.34	0.24–0.48	<0.0001	0.55	0.32–0.81	0.002
II	1001	36	0.89	0.72–1.10	0.275	1.17	0.93–1.48	0.177
III	596	39	1.00			1.00
Location					0.710			0.310
Inner upper	240	30	1.00			1.00
Inner lower	115	29	0.96	0.59–1.56	0.863	1.09	0.65–1.84	0.738
Outer upper	1068	33	1.19	0.88–1.62	0.252	1.26	0.91–1.76	0.165
Outer lower	290	38	1.43	0.99–2.06	0.053	1.49	1.01–2.22	0.044
Central	177	40	1.59	1.06–2.40	0.025	1.39	0.89–2.17	0.151
Palpability
Palpable	1270	41	2.78	2.22–3.49	<0.0001	1.77	1.37–2.29	<0.0001
Not palpable	620	20	1.00			1.00
Preop-biopsy
No	842	30	1.000			1.00
Yes	1048	37	1.37	1.13–1.66	0.001	1.09	0.85–1.40	0.508
Learning period
No	1476	34	0.95	0.76–1.20	0.673	1.13	0.79–1.62	0.509
Yes	414	35	1.00
Department					0.003			0.001
1	252	37	1.00			1.00
2	112	42	1.24	0.78–1.95	0.360	1.75	1.04–2.95	0.036
3	372	29	0.71	0.50–0.99	0.047	0.75	0.50–1.12	0.157
4	283	41	1.20	0.85–1.71	0.294	0.75	0.47–1.18	0.210
5	475	28	0.66	0.48–0.92	0.014	0.56	0.38–0.83	0.004
6	64	33	0.83	0.47–1.49	0.543	0.52	0.24–1.09	0.084
7	68	32	0.82	0.46–1.44	0.488	0.74	0.39–1.40	0.354
8	143	43	1.27	0.84–1.93	0.260	1.35	0.84–2.16	0.216
9	44	36	0.98	0.50–1.90	0.945	1.02	0.45–2.30	0.958
10	29	34	0.90	0.40–2.02	0.798	0.88	0.3–2.32	0.795
11	13	31	0.76	0.23–2.54	0.655	0.74	0.20–2.81	0.664
12	35	25	0.51	0.22–1.16	0.108	0.49	0.19–1.29	0.150
SLN technique					0.087			0.175
Combination	1000	33.5	1.00
Blue dye	501	38	1.27	1.01–1.59	0.037	1.20	0.86–1.68	0.287
Radiotracer	389	32	0.99	0.77–1.28	0.969	1.35	0.96–1.90	0.083
SLN timing
1st procedure	1750	35	1.00			1.00
2nd procedure	140	23	0.59	0.39–0.87	0.008	1.01	0.63–1.62	0.969
Study period
Prospective	1354	34	1.00			1.00
Retrospective	536	35	1.06	0.86–1.31	0.574	0.97	0.70–1.38	0.848