Table 3.

Model 1 – A model estimating the effect of surgical margins on local recurrence (LR) in invasive breast cancer adjusted for covariates (covariates examined in model 1 were selected using criteria described in Analysis)

Covariate (Covariate definition and categories described in Methods)		P for association of covariate with LR		Margin status (adjusted OR)		Threshold distance for negative margins (adjusted OR)				P for association [P for trend] for margin distance
	No of studies	Unadjusted	Adjusted for margins & follow-up time	Negative	Positive/close	> 0 mm	1mm	2mm	5mm	adjusted for covariate
Effect of margins (adjusted for follow-up time)	33			1.0	1.96**	1.47	1.0	0.95	0.65	0.12 [0.21]
Age	32	0.11	0.089	1.0	1.91**	1.56	1.0	1.13	0.72	0.12 [0.29]
Median-year of study recruitment	33	<0.0001	0.0086	1.0	1.96**	1.47	1.0	0.95	0.65	0.26 [0.14]
Proportion had endocrine therapy	27	<0.0001	0.0011	1.0	2.07**	1.11	1.0	0.91	0.77	0.19 [0.32]
Proportion ER-positive	24	0.012	0.023	1.0	2.26**	0.87	1.0	0.98	0.56	0.44 [0.25]
Proportion had re-excision#	17	0.032	0.088	1.0	2.06**	1.41	1.0	0.82	0.52	0.22 [0.13]
LR type (first vs any)§	33	0.12	0.058	1.0	1.96**	1.11	1.0	0.83	0.51	0.063 [0.074]

^**Indicates OR significantly different to referent at P<0.001

^#Odds of LR increased as proportion receiving re-excision increased

^§LT type (see ‘Definition of variables’ in Methods): odds of LR were lower for ‘first’ than ‘any’