Table 1 Baseline characteristics of patients
Characteristics | Training cohort | Validation cohort | |||
|---|---|---|---|---|---|
No. of patients | % | No. of patients | % | ||
Age(year) | |||||
  < 65 | 200 | 29.7 | 91 | 32.9 | |
  ≥ 65 | 474 | 70.3 | 186 | 67.1 | |
Gender | |||||
 Male | 462 | 68.5 | 182 | 65.7 | |
 Female | 212 | 31.5 | 95 | 34.3 | |
Smoking | |||||
 Smoker | 490 | 72.7 | 188 | 67.9 | |
 Never-smoker | 184 | 27.3 | 89 | 32.1 | |
PS | |||||
 0–1 | 211 | 31.3 | 3 | 1.1 | |
  ≥ 2 | 463 | 68.7 | 274 | 98.9 | |
T stage | |||||
 1 | 97 | 14.1 | 23 | 8.3 | |
 2 | 285 | 42.3 | 135 | 48.7 | |
 3 | 147 | 21.8 | 59 | 21.3 | |
 4 | 145 | 21.5 | 60 | 21.7 | |
N stage | |||||
 0 | 92 | 13.6 | 31 | 11.2 | |
 1 | 133 | 19.7 | 60 | 21.7 | |
 2 | 228 | 33.8 | 97 | 35 | |
 3 | 221 | 32.8 | 89 | 32.1 | |
Synchronous BM | |||||
 Yes | 518 | 76.9 | 210 | 75.8 | |
 No | 156 | 23.1 | 67 | 24.2 | |
Number of BM lesion | |||||
 1 | 261 | 38.7 | 107 | 38.6 | |
  ≥ 2 | 413 | 61.3 | 170 | 61.4 | |
Maximum diameter of BM lesion | |||||
  < 2 cm | 360 | 53.4 | 174 | 62.8 | |
  ≥ 2 cm | 314 | 46.6 | 103 | 37.2 | |
Extracranial metastases | |||||
 Yes | 259 | 38.4 | 110 | 39.7 | |
 No | 415 | 61.6 | 167 | 60.3 | |
Cerebral symptoms | |||||
 Yes | 234 | 34.7 | 87 | 31.4 | |
 No | 440 | 65.3 | 190 | 68.6 | |
Receiving local treatment (surgery/wbrt/srs) | |||||
 Yes | 412 | 61.1 | 131 | 47.3 | |
 No | 262 | 38.9 | 146 | 52.7 | |
Receiving chemotherapy | |||||
 Yes | 517 | 76.7 | 217 | 78.3 | |
 No | 157 | 23.3 | 60 | 21.7 | |