Table 2.

Univariate and multivariate analysis for risk factors of IBRT.

Risk Factors	No IBRT (n = 180)	IBRT (n = 27)	Univariate OR and CI (95%)	Multivariate OR and CI (95%)	p
Included in MSKCC:
Age
<50 years	23 (12.8)	4 (14.8)	0.9 (0.9–1.0)	1.0 (0.9–1.1)	0.54
>50 years	157(87.2)	23 (85.2)
Family history
No	86 (47.7)	21 (77.8)
Yes	13 (7.2)	2 (7.4)	0.6 (0.1–3.0)	0.7 (0.1–3.6)	0.54
Unknown	81 (45.0)	4 (14.8)
Clinical presentation
No	171 (95.0)	23 (85.2)	3.3 (0.9–11.6)	7.0 (0.9–52.0)	0.08
Yes	9 (5.0)	4 (14.8)
Radiotherapy
No	28 (15.6)	5 (18.5)	0.8 (0.3–2.8)	1.3 (0.3–6.2)	0.69
Yes	152 (84.4)	22 (81.5)
Endocrine Therapy
No	125 (69.4)	23 (85.1)
Yes	55 (30.6)	4 (14.8)	0.4 (0.1–1.1)	0.4 (0.9–1.4)	0.07
Nuclear grade
1	59 (32.8)	9 (33.3)
2–3	115 (63.8)	15 (55.5)	0.9 (0.3–2.1)	1.2 (0.4–3.7)	0.69
Unknown	6 (3.3)	3 (11.1)
Comedonecrosis
No	78 (43.3)	12 (44.4)
Yes	100 (55.5)	14 (51.8)	0.9 (0.4–2.1)	0.7 (0.2–2.2)	0.82
Unknown	2 (1)	1 (3.7)
Final surgical resection margin
>2 mm	147 (81.7)	19 (70.3)
<2 mm	33 (18.3)	7 (25.9)	1.6 (0.6–4.2)	1.8 (0.5–6.0)	0.31
Unknown	0 (0)	1 (3.7)
Number of reinterventions
1	159 (88.8)	22 (81.4)
2	19 (10.6)	4 (14.8)	1.5 (0.5–4.8)	1.6 (0.5–6.0)	0.49
3	1 (0.0)	0 (0)
Unknown	1 (0.0)	1 (3.7)
Other Risk Factors:
Pathological tumor size
<20 mm	122 (67.8)	20 (74.1)
>20 mm	56 (31.1)	6 (22.2)	0.6 (0.2–1.7)		0.28
Unknown	2 (1.1)	1 (3.7)
Focality
Unifocal	153 (85.0)	23 (85.2)	1.0 (0.3–3.0)		0.97
Multifocal	27 (15.0)	4 (14.8)
Estrogen receptors
Positive	140 (77.8)	14 (51.8)
Negative	25 (13.9)	10 (37.0)	0.3 (0.1–0.6)		0.004
Unknown	15 (8.3)	3 (11.1)
Progesterone receptors
Positive	95 (52.8)	13 (48.1)
Negative	62 (34.4)	11 (40.7)	0.7 (0.3–1.8)		0.55
Unknown	23 (12.8)	3 (11.1)