Table 1 Clinicopathological characteristics of patients with clinically node-negative hormone receptor-positive HER2-negative breast cancer tested with 21-gene recurrence score assay

Median age (range, min–max)

48 (range, 29–72)

Premenopausal

35 (57.4%)

Postmenopausal

26 (42.6%)

Breast Surgery:

 Breast conservation

40 (65.6%)

 Mastectomy

21 (34.4%)

Axillary surgery:

 SLNB

55 (90.2%)

 SLNB&ALND

6 (9.8%)

Type of axillary metastasis:

 Isolated tumor cell (pN0_ITC)

NA

 Micrometastasis (pN_mic)

3 (42.9%)

 Macrometastasis (pN₁)

4 (57.1%)

pT1

49 (80.3%)

pT2

12 (19.7%)

pN0

54 (88.5%)

pN1

7 (11.5%)

TNM Stage (7^th vs. 8^th version)

 Stage 1

44 (72.1%) vs. 53 (86.9%)

 Stage 2

17 (27.9%) vs. 8 (13.1%)

Histopathology:

 Invasive ductal carcinoma

53 (86.9%)

 Invasive lobular carcinoma

5 (8.2%)

 Mucinous & tubular carcinoma

3 (4.9%)

ER positivity

61 (100%)

PR positivity

59 (96.7%)

Histologic Grade:

 Low

12 (19.7%)

 Intermediate

39 (63.9)

 High

10 (16.4%)

Nuclear Grade:

 Low

5 (8.2%)

 Intermediate

40 (65.6%)

 High

16 (26.2%)

LVI( +)

10 (17%)

Median Ki-67 index (%, range)

15 (range, 1–57)

Luminal-A (by IHC)

42 (68.9%)

Recurrence score:

 ^a Low (< 18) / ^bLow (< 11)

10 (16.4%) / 11 (18%)

 ^aIntermediate (18–30) / ^bIntermediate (11–25)

47 (77%) / 43 (70.5%)

 ^a High (≥ 31)/ ^bHigh (> 26)

4 (6.6%) / 7 (11.5%)

Median follow-up

112 (range, 54–154)

Adjuvant chemotherapy

19 (31.1%)

Postmastectomy radiation

2 (9.5%)