Table 1.

Patient characteristics by race/ethnicity

Variable	Total		NHW		HW		AA		Other		P a	Non‐AA		AA		P a
	N	%	N	%	N	%	N	%	N	%		N	%	N	%
Study population	392	100	59	15	241	62	79	20	13	3		313	80	79	20
Age at consent (years)
<50	98	25	18	30	58	24	20	25	2	15	0.776	78	25	20	25	0.733
50–59	156	40	21	36	94	39	34	43	7	54		122	39	34	43
≥60	138	35	20	34	89	37	25	32	4	31		113	36	25	32
Mean (SD)	56.2 (9.1)		55.9 (9.1)		56.5 (9.0)		55.5 (9.4)		57.9 (1.1)			56.4 (9.1)		55.5 (9.4)
Menopausal status
Pre/Peri	128	33	24	41	76	32	25	32	3	23	0.392	103	33	25	32	0.831
Post	264	67	35	59	165	68	54	68	10	77		210	67	54	68
BMI (kg/m2)
<25	101	26	28	47	55	23	13	16	5	38	≤0.001	88	28	13	16	≤0.001
25–29.99	133	34	17	29	94	39	18	23	4	31		115	37	18	23
≥30	158	40	14	24	92	38	48	61	4	31		110	35	48	61
Mean (SD)	29.4 (6.4)		27.0 (6.6)		29.0 (5.2)		32.5 (8.4)		28.6 (6.7)			28.6 (5.6)		32.5 (8.4)
Smoking history
Never	260	66	38	64	156	65	56	71	10	77	0.583	204	65	56	71	0.337
Ever	132	34	21	36	85	35	23	29	3	23		109	35	23	29
Number of comorbiditiesb
0	154	39	27	46	102	42	20	25	5	38	0.066	134	43	20	25	0.013
1	146	37	20	34	87	36	35	44	4	31		111	35	35	44
2	66	17	7	12	36	15	20	26	3	23		46	15	20	26
≥3	26	7	5	8	16	7	4	5	1	8		22	7	4	5
Disease stage
0	79	20	7	12	53	22	15	19	4	31	0.013	64	20	15	19	0.022
I	193	49	38	64	120	50	30	38	5	38		163	52	30	38
II–III	120	31	14	24	68	28	34	43	4	31		86	28	34	43
Histology
DCIS (ductal carcinoma in situ)	85	22	8	14	57	24	16	20	4	31	0.692	69	22	16	20	0.954
IDC (invasive ductal carcinoma)	289	74	48	81	172	71	60	76	9	69		229	73	60	76
ILC (invasive lobular carcinoma)	17	4	3	5	11	5	3	4	–	–		14	5	3	4
Other	1	0	–	–	1	0	–	–	–	–		1	0	–	–
ER
Positive	299	76	43	73	193	80	52	66	11	85	0.025	247	79	52	66	0.013
Negative	92	24	16	27	47	20	27	34	2	15		65	21	27	34
PR
Positive	263	67	37	63	169	71	48	61	9	69	0.186	215	69	48	61	0.156
Negative	127	33	22	37	70	29	31	39	4	31		96	31	31	39
HER2
Positive	38	12	5	9	24	12	8	12	1	11	0.791	30	12	8	12	0.920
Negative	285	88	50	91	169	88	58	88	8	89		227	88	58	88
Triple negative
No	317	85	48	86	201	89	57	73	11	85	0.003	260	88	57	73	≤0.001
Yes	56	15	8	14	25	11	21	27	2	15		35	12	21	27
Chemotherapy therapy
No	191	49	28	48	119	49	41	52	3	23	0.869	150	48	41	52	0.306
Yes	201	51	31	52	122	51	38	48	10	77		163	52	38	48
Hormone therapy
No	133	34	17	29	75	31	40	51	1	8	0.004	93	30	40	51	≤0.001
Yes	257	66	42	71	165	69	39	49	11	92		218	70	39	49
Fractionation
Hypofractionated	67	17	12	21	41	17	12	15	2	15	0.698	55	18	12	15	0.560
Conventionally fractionated	323	83	46	79	199	83	67	85	11	85		256	82	67	85
Lumpectomy cavity boost
No	48	12	4	7	29	12	13	17	2	15	0.239	35	11	13	17	0.209
Yes	342	88	54	93	211	88	66	83	11	85		276	89	66	83
Breast volume (cc)
<881.3 (Median)	193	50	37	64	125	53	22	28	9	69	≤0.001	171	55	22	28	≤0.001
≥881.3	193	50	21	36	112	47	56	72	4	31		137	45	56	72
Mean (SD)	999 (534)		820 (479)		976 (484)		1219 (638)		906 (583)			944 (990)		1219 (638)
Percentage of breast volume with >105% prescription dose
<51.3 (75th percentile)	261	75	38	69	159	76	57	79	7	58	0.419	204	74	57	79	0.337
≥51.3	88	25	17	31	51	24	15	21	5	42		73	26	15	21
Mean (SD)	34.9 (24.8)		38.2 (26.1)		34.2 (24.6)		31.6 (24.5)		51.8 (17.5)			35.7 (24.9)		31.6 (24.5)
Percentage of breast volume with >110% prescription dose
0	184	53	28	51	114	54	39	54	3	25	0.889	145	52	39	54	0.805
>0	164	47	27	49	95	46	33	46	9	75		131	48	33	46
Mean (SD)	16.1 (23.0)		24.3 (22.8)		13.5 (22.5)		16.1 (24.4)		18.8 (21.9)			16.1 (22.7)		16.1 (24.4)

AA, Black or African American; HW, Hispanic white; NHW, non‐Hispanic white; SD, standard deviation; %, column percentage, except for table first row showing row percentage (distribution of study population by race/ethnicity).

^a P‐value from chi‐squared test or Fisher's exact test excluding other race category and missing.

^bSum of 11 patient‐reported comorbidity conditions: diabetes, hypertension, heart disease, lung disease, thyroid condition, cirrhosis liver, stroke, chronic bronchitis, hepatitis, tuberculosis, etc.

Bold values indicate statistically significant findings at p < 0.05.