Table 1.

Patients’ demographics and clinicalpathologic characteristics

Characteristics	Training Cohort		Validation Cohort		All Patients
	N = 527 (%)		N = 880 (%)		N = 1407 (%)
Median follow-up (IQR)	79 (64–97)		22 (9–37)		37 (15–69)
Median age at diagnosis (IQR)	60 (51–70)		61 (52–70)		61 (51–70)
Ethnicity
White	418	79.32	675	76.70	1093	77.68
Black	60	11.39	111	12.61	171	12.15
Others	49	9.30	94	10.68	143	10.16
Gender
Male	4	0.76	21	2.39	25	1.78
Female	523	99.24	859	97.61	1382	98.22
Laterality
Left	281	53.32	443	50.34	724	51.46
Right	246	46.68	437	49.66	683	48.54
Tumor size(cm)
<2	283	53.70	461	52.39	744	52.88
2–5	189	35.86	316	35.91	505	35.89
≥ 5	55	10.44	103	11.70	158	11.23
ER status
Positive	458	86.91	801	91.02	1259	89.48
Negative	69	13.09	79	8.98	148	10.52
PR status
Positive	388	73.62	707	80.34	1095	77.83
Negative	139	26.38	173	19.66	312	22.17
HER2 status
Positive	NA	NA	171	19.43	171	12.15
Negative	NA	NA	679	77.16	679	48.26
Borderline	NA	NA	22	2.50	22	1.56
Unknown	NA	NA	8	0.91	8	0.57
Histological grade
I	48	9.11	53	6.02	101	7.18
II	247	46.87	499	56.70	746	53.02
III	216	40.99	307	34.89	523	37.17
Unknown	16	3.04	21	2.39	37	2.63
Regional lymph nodes
Positive	263	49.91	447	50.80	710	50.46
Negative	264	50.09	433	49.20	697	49.54
Stage
I	196	37.19	328	37.27	524	37.24
II	211	40.04	343	38.98	554	39.37
III	113	21.44	194	22.05	307	21.82
IV	5	0.95	8	0.91	13	0.92
Unknown	2	0.38	7	0.80	9	0.64

IQR interquartile range, ER estrogen receptor, PR progesterone receptor, HER2 human epidermal growth factor 2