Table 1. Characteristics of the patients in the discovery and validation cohorts.

	Discovery cohort		Validation cohort				P value between A and B	P value between B and C
	Hormone therapy alone (A) (n = 174)		Hormone therapy alone (B) (n = 222)		Hormone therapy plus chemotherapy (C) (n = 510)
	No. of patients	%	No. of patients	%	No. of patients	%
DMFS rate at 10 years (%)	92.0% (87.9%–96.3%)		92.2% (88.0%–96.6%)		84.7% (81.4%–88.2%)
Median age (range), years	53.8 (24.3–80.5)		50.0 (29.0–80.0)		46.0 (25.2–67.7)		<0.002c	<0.013c
Age, years							0.052a	<0.001a
<50	66	37.9%	107	48.2%	352	69.0%
≥50	108	62.1%	115	51.8%	158	31.0%
Menopausal status							<0.002a	0.004a
Pre	65	37.4%	115	51.8%	204	40.0%
Post	89	51.1%	77	34.7%	75	14.7%
NA	20	11.5%	30	13.5%	231	45.3%
pN							0.520a	<0.001a
0	163	93.7%	203	91.4%	322	63.1%
1	11	6.3%	19	8.6%	188	36.9%
Tumor size (cm)							0.693a	<0.001b
≤2	141	81.0%	184	82.9%	252	49.4%
2–5	33	19.0%	38	17.1%	251	49.2%
>5	0	0.0%	0	0.0%	7	1.4%
Pathologic stage							0.624a	<0.001a
IA	136	78.2%	177	79.7%	153	30.0%
IIA	31	17.8%	33	14.9%	258	50.6%
IIB	7	4.0%	12	5.4%	99	19.4%
Histologic grade							0.002a	0.203a
1	53	30.5%	36	16.2%	80	15.7%
2	103	59.2%	148	66.7%	313	61.4%
3	18	10.3%	38	17.1%	117	22.9%
NPI							0.257a	<0.001a
1	130	74.7%	154	69.4%	156	30.6%
2	36	20.7%	49	22.1%	211	41.4%
3	8	4.6%	19	8.5%	143	28.0%

Abbreviations: DMFS, distant metastasis-free survival; NA, not available; No., number; NPI, Nottingham Prognostic Index; pN, pathological nodal status.

^aChi-square test; ^bFisher’s exact test; ^cStudent’s t-test. P values < 0.05 are marked in bold.