Table 2.
Patient characteristics and information on brain metastases
| Developmental set | Validation set | |||
|---|---|---|---|---|
| Site 1 | Site 1 | Site 2 | P-value | |
| Number of patients | 101 | 123 | 120 | |
| Age | 61.4 ± 9.2 | 65.0 ± 9.7 | 62.6 ± 11.9 | 0.08 |
| Male Sex | 60 (59.4) | 68 (55.3) | 72 (60) | 0.42 |
| BM Number | 864 | 2078 | 832 | |
| Average number of BM for each patient | 8.6 ± 9.6 | 8.7 ± 12.2 | 7.0 ± 6.6 | 0.015 |
| Patients with > 10 numbers of BM | 20 (19.8) | 32 (26.0) | 19 (16.8) | 0.050 |
| Volume and size (mm3) of BM | ||||
| Mean ± SD (volume, mm3) | 204.9 ± 811.8 | 211.5 ± 1406.9 | 345.7 ± 1569.4 | 0.024 |
| Mean ± SD (diameter, mm) | 4.69 ± 3.57 | 4.53 ± 3.52 | 4.45 ± 4.55 | 0.625 |
| BM numbers less than 5 mm in diameter | 689 (79.5) | 1697 (81.6) | 619 (75.6) | 0.378 |
| Primary tumor types | 0.587 | |||
| Lung adenocarcinoma | 85 (84.2) | 115 (93.5) | 110 (91.6) | |
| Lung squamous cell carcinoma | 5 (4.9) | 8 (6.5) | 10 (8.3) | |
| Lung other types of cancer | 2 (1.9) | |||
| Breast cancer | 5 (4.9) | |||
| Colon cancer | 2 (1.9) | |||
| Renal cancer | 4 (1.9) | |||
Data are expressed as the mean ± standard deviation or numbers with percentages in parentheses. P value indicates statistical significance between two hospitals in the validation set
Abbreviation BM = brain metastasis; SD = standard deviation