Table 3. Characteristics of the validation study population.
| Total | CERneg | CERimp | CERhi | |
|---|---|---|---|---|
| N (%) | N (%) | N (%) | N (%) | |
|
Age (years) | ||||
| <50 | 68 (15) | 15 (27) | 18 (12) | 35 (14) |
| ⩾50 | 387 (85) | 40 (73) | 130 (88) | 217 (86) |
|
Grade | ||||
| 1 | 77 (17) | 22 (15) | 55 (22) | |
| 2 | 209 (46) | 5 (9) | 66 (45) | 138 (55) |
| 3 | 168 (37) | 50 (91) | 60 (40) | 58 (23) |
| Unknown | 1 (<1) | 1 (<1) | ||
|
Lymph node | ||||
| 0 | 311 (68) | 36 (66) | 94 (64) | 181 (72) |
| 1–3 | 97 (21) | 11 (20) | 31 (21) | 55 (22) |
| >3 | 46 (10) | 8 (14) | 23 (15) | 15 (6) |
| Unknown | 1 (<1) | 1 (<1) | ||
|
Size (mm) | ||||
| <20 | 254 (56) | 18 (33) | 74 (51) | 162 (64) |
| 20–50 | 176 (39) | 35 (64) | 61 (41) | 80 (32) |
| >5 | 13 (3) | 2 (3) | 8 (5) | 3 (1) |
| Unknown | 12 (3) | 5 (3) | 7 (3) | |
|
ER Allred score | ||||
| <3 | 57 (12) | 55 (100) | 2 (1) | |
| 3–5 | 21 (5) | 21 (14) | ||
| 6–8 | 377 (83) | 125 (85) | 252 (100) | |
|
PR Allred score | ||||
| <3 | 111 (24) | 55 (100) | 56 (38) | |
| 3–5 | 90 (20) | 90 (61) | ||
| 6–8 | 254 (56) | 2 (1) | 252 (100) | |
|
HER2 | ||||
| Positive | 70 (15) | 18 (33) | 35 (24) | 17 (7) |
| Negative | 382 (84) | 37 (67) | 111 (75) | 234 (93) |
| Unknown | 3 (<1) | 2 (1) | 1 (<1) | |
|
Surgical operation | ||||
| Mastectomy | 131 (29) | 24 (44) | 44 (30) | 63 (25) |
| Conservation | 324 (72) | 31 (56) | 104 (70) | 189 (75) |
|
Endocrine therapy | ||||
| Yes | 392 (86) | 2 (4) | 140 (95) | 250 (99) |
| Tamoxifen | 184 (40) | 57 (39) | 127 (50) | |
| AI | 138 (30) | 2 (4) | 57 (39) | 79 (31) |
| Early switch | 46 (10) | 14 (9) | 32 (12) | |
| Late switch | 24 (5) | 12 (8) | 12 (5) | |
| No | 63 (14) | 53 (96) | 8 (5) | 2 (<1) |
|
Chemotherapy | ||||
| Yes | 166 (37) | 40 (73) | 59 (40) | 67 (27) |
| No | 289 (63) | 15 (27) | 89 (60) | 185 (73) |
|
Biological therapy | ||||
| Yes | 50 (11) | 14 (25) | 24 (16) | 12 (5) |
| No | 405 (89) | 41 (75) | 124 (84) | 240 (95) |
Abbreviations: AI=aromatase inhibitor; CER=combined endocrine receptor; ER=oestrogen receptor; HER2=human epidermal growth factor receptor 2; hi=high; imp=impaired; neg=negative; PR=progesterone receptor.
For the validation population study, patient and tumour characteristics in the column titled ‘total' are recategorised according to the CER classification. Patients received endocrine therapy in the form of tamoxifen monotherapy, AI monotherapy, early switch within 5 years AI-tamoxifen or vice versa and extended switch, 5 years on AI switched to tamoxifen or vice versa.