Table 1 Patient and tumor characteristics for the derivation and validation sets

No of patients

4477

1132

Distant recurrences ^a

1315 (29)^b

289 (26)

Age median, years

60

64

Age range, years

25–93

28–99

 Age < 35

69 (2)

11 (1)

 Age 35–50

1023 (23)

202 (18)

 Age > 50

3385 (76)

919 (81)

Tumor size median, mm

22

20

Tumor size range, mm

1–120

1–160

 T1 (≤20 mm)

1942 (43)

590 (52)

 T2 (21–50 mm)

2460 (55)

506 (45)

 T3 (> 50 mm)

75 (2)

36 (3)

Lymph nodes median

1

0

Lymph nodes range

0–47

0–23

 Negative

1783 (40)

659 (58)

 1–3 positive

1781 (40)

305 (27)

 4–9 positive

649 (14)

127 (11)

 ≥ 10 positive

264 (6)

41 (4)

 Endocrine therapy

2662 (59)

673 (59)

 Chemotherapy

460 (10)

52 (5)

 Chemo-endocrine

74 (2)

38 (3)

 None

1279 (29)

369 (33)

 Missing

2

0