TABLE 1.
Baseline Characteristics and Treatment Response of All 142 Spinal Segments Included in the Study
| Variable | |
|---|---|
| Primary cancer site | N (%) |
| Breast | 57 (40.1) |
| Colorectal | 8 (5.6) |
| Nonsmall cell lung carcinoma | 20 (14.1) |
| Melanoma | 2 (1.4) |
| Prostate | 23 (16.2) |
| Renal cell carcinoma | 23 (16.2) |
| Squamous cell carcinoma | 3 (2.1) |
| Other* | 4 (2.8) |
| Unknown | 2 (1.4) |
| Spine metastatic location | N (%) |
| Cervical | 9 (6.3) |
| Thoracic | 83 (58.5) |
| Lumbar | 36 (25.3) |
| Sacral | 14 (9.9) |
| Epidural disease at the treated segment17 | N (%) |
| 0 | 105 (73.9) |
| 1a | 15 (10.6) |
| 1b | 16 (11.3) |
| 1c | 5 (3.5) |
| 2 | 1 (0.7) |
| 3 | 0 (0) |
| Spinal metastases tumor type | N (%) |
| Sclerotic | 52 (36.7) |
| Lytic | 66 (46.5) |
| Mixed | 24 (16.9) |
| Treatment | N (%) |
| 24 Gy/2 fractions | 142 (100.0) |
| Time between scans | Median (IQR) in days |
| Post1 | 89 (74-103) days after baseline |
| Post2 | 91 (67-107) days after Post1 |
| Contoured GTV sizes | Median (IQR) in cc |
| Baseline | 5.6 (1.2-10.2) |
| Post1 | 4.4 (1.0-10.6) |
| Post2 | 4.0 (0.9-8.9) |
| 1-yr RSS PFS | N (%) |
| No progression | 125 (88.0) |
| Progression | 17 (12.0) |
| Small tumors (GTV < 2 cc) | 5/17 (29.4) |
| Medium tumors (2 ≤ GTV ≤ 8.3 cc) | 6/17 (35.3) |
| Large tumors (GTV > 8.3 cc) | 6/17 (35.3) |
Abbreviations: Gy, Gray; IQR, interquartile range; GTV, gross tumor volume; RSS PFS, radiation site-specific progression-free survival.
*
Primaries were uterine, hepatocellular carcinoma, and neuroendocrine tumors.