Table 5.

Multivariable Cox regression analysis of recurrence, stratified by use of radiation

Variable		No radiation (N=1225)*				Radiation (N=1483)*
		N	Events	HR	P	N	Events	HR	P
Age at surgery	Per year			0.987	0.02			0.956	<0.0001
Family history	No	753	114	1	0.05	909	73	1	0.23
	Yes	472	87	1.32		574	51	1.25
Presentation	Radiologic	1068	162	1	0.06	1326	102	1	0.43
	Clinical	157	39	1.4		157	22	1.22
Number of excisions	1	688	100	1	0.0003	612	38	1	0.66
	2	492	85	1.37		712	70	1.18
	≥3	45	16	3.18		159	16	1.30
Endocrine therapy	No	1026	180	1	0.003	1084	105	1	0.002
	Yes	199	21	0.50		399	19	0.46
Year of surgery	1978–2000	459	123	1.60	0.003	367	65	1.18	0.44
	2001–2010	766	78	1		1116	59	1
Margin width	Positive	40	10	1	<0.0001	58	6	1	0.95
	Close (≤2mm)	167	42	0.75		268	27	0.95
	>2–10mm	369	62	0.58		492	35	1.00
	>10mm	649	87	0.31		665	56	0.88

^*In entire population of 2996, 288 cases had at least one missing data point, resulting in population for multivariable analysis of 2708.

HR, hazard ratio