Table 1.

Patients, tumor, and systemic therapy characteristics

	IOERT boost arm	EBRT boost arm	p value
Women in each arm	125 (51%)	110 (49%)
Median age (range)	56.3 years (29–75)	56.2 years (34–75)	0.96**
Menopausal status			0.81*
Pre	37 (30%)	31 (28%)
Post	88 (70%)	79 (72%)
Disease laterality			0.73*
Right breast	54 (43%)	50 (45%)
Left breast	71 (57%)	60 (55%)
Histology			0.46*
IDC	61 (49%)	59 (54%)
ILC	17 (14%)	11 (10%)
DCIS	3 (1.4%)	3 (2.6%)
IDC+DCIS	32 (26%)	24 (22%)
Medullary	6 (5%)	4 (3.5%)
ILC+ILCS	5 (4%)	5 (4.4%)
Missing	1 (0.6%)	4 (3.5%)
Pathologic T stage			0.38*
pT1	96 (77%)	79 (72%)
pT2	28 (22%)	22 (20%)
pT3–pT4	1 (1%)	1 (1%)
Missing	0	8 (7%)
Pathologic N stage			0.55*
pN0	82 (65%)	68 (62%)
pN1	38 (30%)	32 (29%)
pN2	2 (2.1%)	1 (1%)
pN3	1 (0.8%)	1 (1%)
Missing	2 (2.1%)	8 (7%)
Adjuvant chemotherapy			0.61*
Yes	37 (30%)	36 (33%)
Not	85 (68%)	64 (58%)
Missing	3 (2%)	10 (9%)
Hormone therapy			0.66*
Yes	105 (84%)	90 (81%)
Not	19 (15%)	12 (11%)
Missing	1 (1%)	8 (8%)

Abbreviations: IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; DCIS, ductal carcinoma in situ

**Mann-Whitney test

*Chi-square test