Table 1.
Clinical feature distributions for number of BMs, BMs progressing post-SRS, and patients (where applicable) for the study sample.
| Clinical features | # Patients | # BMs (% progression) |
|---|---|---|
| Sex (p = 0.831) | ||
| Female | 55 | 66 (21.2%) |
| Male | 44 | 57 (22.8%) |
| Age (p = 0.925) | ||
| Median (range) | 58.0 (38.4–86.0) years | |
| Primary cancer active (p = 0.002) | ||
| Yes | 44 | 55 (9.1%) |
| No | 55 | 68 (32.4%) |
| Primary cancer site (p = 0.003) | ||
| Lung | 59 | 70 (12.9%) |
| Breast | 10 | 14 (35.7%) |
| Renal | 10 | 15 (13.3%) |
| Colorectal | 8 | 10 (40.0%) |
| Skin | 8 | 9 (66.7%) |
| Other | 4 | 5 (20.0%) |
| Primary cancer histology (p = 0.001) | ||
| Adenocarcinoma | 49 | 65 (20.0%) |
| NSCLC | 31 | 36 (11.1%) |
| Melanoma | 8 | 9 (66.7%) |
| Squamous carcinoma | 7 | 8 (50.0%) |
| Other | 4 | 5 (0.0%) |
| Extracranial systemic metastases (p = 0.665) | ||
| Yes | 39 | 50 (20.0%) |
| No | 60 | 73 (23.3%) |
| Systemic therapy status (p = 0.033) | ||
| Radical | 51 | 10 (20.0%) |
| Palliative | 41 | 60 (31.7%) |
| None | 7 | 53 (11.3%) |
| Neurological symptoms steroid response (p = 0.426) | ||
| Fully resolved | 48 | 31 (16.1%) |
| Improvement | 7 | 4 (50.0%) |
| Limited improvement | 4 | 56 (25.0%) |
| No improvement | 26 | 11 (9.1%) |
| Unknown | 14 | 21 (23.8%) |
| ECOG/WHO performance score (p = 0.580) | ||
| 0 | 31 | 39 (17.9%) |
| 1 | 60 | 73 (21.9%) |
| 2 | 6 | 9 (33.3%) |
| 3 | 2 | 2 (50.0%) |
| GTV volume (p < 0.001) | ||
| Median (range) | 3.07 (0.02–30.23) cc | |
| < 7.5 cc | – | 94 (17.0%) |
| > 7.5 cc | – | 29 (37.9%) |
| BM location (p = 0.626) | ||
| Supratentorial | – | 96 (22.9%) |
| Infratentorial | – | 27 (18.5%) |
| SRS prescription (p = 0.003) | ||
| 15 Gy in 1 fraction | – | 5 (0.0%) |
| 18 Gy in 1 fraction | – | 36 (30.6%) |
| 21 Gy in 1 fraction | – | 72 (13.9%) |
| 24 Gy in 3 fractions | – | 10 (60.0%) |
The “Neurological Symptoms Steroid Response” feature qualitatively scores the improvement of neurological symptoms after the administration of steroids, based on the previously reported methodology of Lagerwaard et al.24. p-values provided for statistical comparisons between BMs that progressed and did not progress post-SRS. The Wilcoxon rank sum test was used for continuous features (age and GTV volume). The Chi-squared test was used for the remaining categorical features. NSCLC non-small cell lung cancer, ECOG Eastern Cooperative Oncology Group, WHO World Health Organization.