Table 1 Demographic and clinicopathological characteristics of patients in the training and validation cohorts before and after multiple imputation
Characteristics | Trainingcohort before imputation | Training cohort after imputation | Validation cohort before imputation | Validation cohort after imputation | P | ||||
|---|---|---|---|---|---|---|---|---|---|
| Â | N | % | N | % | N | % | N | % | Â |
Age | 0.302 | ||||||||
Median (range) | 48 (26–88) |  | 48 (26–88) |  | 46 (20–87) |  | 46 (20–87) |  |  |
 ≤35 | 35 | 11.8 | 35 | 11.8 | 25 | 13.1 | 25 | 13.1 |  |
 36–50 | 138 | 46.6 | 138 | 46.6 | 100 | 52.4 | 100 | 52.4 |  |
 >50 | 123 | 41.6 | 123 | 41.6 | 66 | 34.6 | 66 | 34.6 |  |
Marital status | |||||||||
 Married | 281 | 94.9 | 281 | 94.9 |  |  |  |  |  |
 Unmarried | 15 | 5.1 | 15 | 5.1 |  |  |  |  |  |
Family history of breast cancer | |||||||||
 Yes | 34 | 11.5 | 34 | 11.5 |  |  |  |  |  |
 No | 262 | 88.5 | 262 | 88.5 |  |  |  |  |  |
Menopausal status | |||||||||
 Premenopausal | 174 | 58.8 | 174 | 58.8 |  |  |  |  |  |
 Postmenopausal | 122 | 41.2 | 122 | 41.2 |  |  |  |  |  |
Histology | 0.329 | ||||||||
 Ductal | 274 | 92.6 | 274 | 92.6 | 172 | 90.1 | 172 | 90.1 |  |
 Lobular/other | 22 | 7.4 | 22 | 7.4 | 19 | 9.9 | 19 | 9.9 |  |
Grade | 0.890 | ||||||||
 I | 11 | 3.7 | 15 | 5.1 | 11 | 5.8 | 11 | 5.8 |  |
 II | 49 | 16.6 | 54 | 18.2 | 37 | 19.4 | 37 | 19.4 |  |
 III | 181 | 61.1 | 227 | 75.0 | 143 | 74.9 | 143 | 74.9 |  |
 Unknown | 55 | 18.6 | 0 | 0.0 | |||||
Tumor size | 0.414 | ||||||||
 ≤2 cm | 152 | 51.4 | 152 | 51.4 | 98 | 51.3 | 98 | 51.3 |  |
 2-5 cm | 120 | 40.5 | 120 | 40.5 | 71 | 37.2 | 71 | 37.2 |  |
 >5 cm | 24 | 8.1 | 24 | 8.1 | 22 | 11.5 | 22 | 11.5 |  |
Node status | 0.630 | ||||||||
 N0 | 172 | 58.1 | 172 | 58.1 | 108 | 56.5 | 108 | 56.5 |  |
 N1 | 73 | 24.7 | 73 | 24.7 | 54 | 28.3 | 54 | 28.3 |  |
 N2 + N3 | 51 | 17.2 | 51 | 17.2 | 29 | 15.2 | 29 | 15.2 |  |
Stage | 0.958 | ||||||||
 I | 97 | 32.8 | 97 | 32.8 | 65 | 34.0 | 65 | 34.0 |  |
 II | 141 | 47.6 | 141 | 47.6 | 89 | 46.6 | 89 | 46.6 |  |
 III | 58 | 19.6 | 58 | 19.6 | 37 | 19.4 | 37 | 19.4 |  |
Ki67 index | 0.150 | ||||||||
 <40% | 111 | 37.5 | 126 | 42.6 | 86 | 45.0 | 94 | 49.2 |  |
 ≥40% | 139 | 47.0 | 170 | 57.4 | 92 | 48.2 | 97 | 50.8 |  |
 Unknown | 46 | 15.5 | 0 | 0.0 | 13 | 6.8 | 0 | 0.0 | |
sTIL group (%) | 0.146 | ||||||||
 0–9 | 61 | 20.6 | 61 | 20.6 | 25 | 13.1 | 25 | 13.1 |  |
 10–19 | 79 | 26.7 | 79 | 26.7 | 62 | 32.5 | 62 | 32.5 |  |
 20–49 | 85 | 28.7 | 85 | 28.7 | 60 | 31.4 | 60 | 31.4 |  |
 ≥50 | 71 | 24.0 | 71 | 24.0 | 44 | 23.0 | 44 | 23.0 |  |
Surgery type | |||||||||
 Mastectomy | 135 | 45.6 | 135 | 45.6 |  |  |  |  |  |
 Lumpectomy | 161 | 54.4 | 161 | 54.4 |  |  |  |  |  |
Radiotherapy | |||||||||
 Yes | 197 | 66.6 | 197 | 66.6 |  |  |  |  |  |
 No | 99 | 33.4 | 99 | 33.4 |  |  |  |  |  |
Chemotherapy type | |||||||||
 Neoadjuvant | 62a | 20.9 | 62a | 20.9 | 34b | 17.8 | 34b | 17.8 | 0.515 |
 Adjuvant | 222 | 75.0 | 222 | 75.0 | 146 | 76.4 | 146 | 76.4 |  |
 No chemotherapy | 12 | 4.1 | 12 | 4.1 | 11 | 5.8 | 11 | 5.8 |  |
Chemotherapy regimen | |||||||||
 anthracycline-based | 70 | 24.6 | 70 | 24.6 | 44 | 24.4 | 44 | 24.4 | 0.622 |
taxane-based | 72 | 25.4 | 72 | 25.4 | 39 | 21.7 | 39 | 21.7 | Â |
 anthracycline& taxane -based | 142 | 50.0 | 142 | 50.0 | 97 | 53.9 | 97 | 53.9 |  |