Table 3.

Hazard ratios for invasive ipsilateral breast tumor recurrence (I-IBTR) or ductal carcinoma in situ (DCIS)-IBTR according to patient and disease characteristics^*

Characteristic	Ipsilateral breast tumor events
	I-IBTR		DCIS-IBTR
	HR (95% CI)	P	HR (95% CI)	P
Age at diagnosis, y
≥65	1.00 (reference)	.003	1.00 (reference)	<.001
<45	2.14 (1.40 to 3.26)		2.90 (1.84 to 4.56)
45–54	1.80 (1.22 to 2.66)		1.81 (1.16 to 2.81)
55–64	1.50 (1.00 to 2.26)		1.72 (1.10 to 2.70)
Tumor size, cm
≤1.0	1.00 (reference)		1.00 (reference)
>1.0	0.94 (0.68 to 1.30)	.70	1.03 (0.73 to 1.44)	.89
Mode of detection
Mammography only	1.00 (reference)		1.00 (reference)
Clinically detected	1.37 (1.03 to 1.84)	.03	1.48 (1.09 to 2.01)	.01
Comedonecrosis†,‡
Absent	1.00 (reference)		1.00 (reference)
Present	0.87 (0.62 to 1.21)	.41	2.21 (1.52 to 3.20)	<.001
Treatment group, tumor margin status†,§
LRT, margin-free	1.00 (reference)		1.00 (reference)
LRT, involved/uncertain	2.61 (1.68 to 4.05)	<.001	1.65 (1.00 to 2.73)	.05
LRT + TAM, free	1.00 (reference)		1.00 (reference)
LRT + TAM, involved/uncertain	1.27 (0.73 to 2.20)	.40	1.32 (0.77 to 2.28)	.31

^*Two-sided Wald test for model coefficient(s) representing the covariate. CI = confidence interval; HR = hazard ratio; LRT = lumpectomy followed by radiation therapy; LRT + TAM = LRT plus 5 years of tamoxifen.

^†Patients from B-24 trial only, based on institutional reports.

^‡For 36 patients (2.0%), comedonecrosis was unknown.

^§A statistically significant interaction between treatment group and tumor margin status was noted (two-sided Wald test, P = .04).