Table 4. Clinical and pathological characteristics of the validation cohort of 88 breast cancer patients.

Characteristics		Cases	Percentage (%)
Menopause at diagnosis	Premenopause	68	77.3
	Postmenopause	20	22.7
Tumor size	T ≤ 2 cm	21	23.9
	2 cm < T ≤ 5 cm	53	60.2
	T > 5 cm	11	12.5
	Unknown	3	3.4
Lymph node involvement	Negative	38	43.2
	Positive	49	55.7
	Unknown	1	1.1
Clinical stage	I	17	19.3
	II	41	46.6
	III	27	30.7
	Unknown	3	3.4
Tumor histology	Invasive ductal carcinoma	80	90.9
	Other invasive carcinoma a	8	9.1
Tumor grade	I/II	35	39.8
	III	48	54.5
	Unknown	5	5.7
Molecular subtype	Luminal A	24	27.3
	Luminal B	49	55.7
	Unknown	15	17.0
ER	Negative	8	9.1
	Positive	80	90.9
PR	Negative	8	9.1
	Positive	80	90.9
Ki67	< 14%	33	37.5
	≥ 14%	49	55.7
	Unknown	6	6.8
HER2	Negative	76	86.4
	Positive	5	5.7
	Uncertain	7	8.0
Menopause when receiving tamoxifen	Premenopause	63	71.6
	Postmenopause	23	26.1
	Unknown	2	2.3
Adjuvant chemotherapy	No	4	4.5
	Yes	84	95.5
Adjuvant radiotherapy	No	43	48.9
	Yes	45	51.1
Characteristics		Median (range)
Age at diagnosis (year)		45 (25~71)
Months of tamoxifen adminstration by relapse		60.9 (1.0~137.1)
Follow-up months after tamoxifen administration		96.4 (16.2~165.1)

^aMucinous adenocarcinoma, invasive lobular carcinoma, invasive micropapillary carcinoma, and mixed type carcinoma.