Table 1.
Baseline clinical characteristics of patients with spinal metastases with radiologic imaging (n = 182)
| Overall (N = 182) |
Patients with local failure (n = 74) |
Patients without local failure (n = 108) |
Comparison of baseline characteristics (with vs without local failure) |
||||
|---|---|---|---|---|---|---|---|
| No. | % | No. | % | No. | % | P value | |
| Age at RT start (years) | |||||||
| Median | 60.5 | - | 59.5 | - | 61 | - | - |
| Range | 23-97 | - | 38-97 | - | 23-87 | - | - |
| Sex | |||||||
| Female | 100 | 54.9 | 35 | 47.3 | 65 | 60.2 | .086 |
| Male | 82 | 45.1 | 39 | 52.7 | 43 | 39.8 | |
| Time from metastatic diagnosis to RT start (years) | |||||||
| Median | 0.7 | - | 0.9 | - | 0.5 | - | - |
| Range | 0-12.4 | - | 0-9.1 | - | 0-12.4 | - | - |
| ECOG PS | |||||||
| 0 | 35 | 19.2 | 16 | 21.6 | 19 | 17.6 | .835 |
| 1 | 97 | 53.3 | 37 | 50 | 60 | 55.6 | |
| 2 | 34 | 18.7 | 15 | 20.3 | 19 | 17.6 | |
| 3 | 16 | 8.8 | 6 | 8.1 | 10 | 9.3 | |
| Histology | |||||||
| Breast | 40 | 22.0 | 9 | 12.2 | 31 | 28.7 | .013 |
| Lung | 43 | 23.6 | 17 | 23.0 | 26 | 24.1 | |
| Prostate | 32 | 17.6 | 17 | 23.0 | 15 | 13.9 | |
| Kidney | 10 | 5.5 | 8 | 10.8 | 2 | 1.8 | |
| Melanoma | 7 | 3.8 | 2 | 2.7 | 5 | 4.6 | |
| Other∗ | 50 | 27.5 | 21 | 28.4 | 29 | 26.9 | |
| Metastatic burden† | |||||||
| 1 | 41 | 22.5 | 18 | 24.3 | 23 | 21.3 | .497 |
| 2 | 58 | 31.9 | 24 | 32.4 | 34 | 31.5 | |
| 3 | 42 | 23.1 | 13 | 17.6 | 29 | 26.9 | |
| ≥4 | 41 | 22.5 | 19 | 25.7 | 22 | 20.4 | |
| Spine level | |||||||
| Cervical | 8 | 4.4 | 4 | 5.4 | 4 | 3.7 | .559 |
| Thoracic | 84 | 46.2 | 30 | 40.5 | 54 | 50.0 | |
| Lumbar | 74 | 40.7 | 34 | 45.9 | 40 | 37.0 | |
| Spine | 16 | 8.8 | 6 | 8.1 | 10 | 9.3 | |
| SINS | |||||||
| 0-6 | 71 | 39.0 | 28 | 37.8 | 43 | 39.8 | .786 |
| 7-12 | 99 | 54.4 | 40 | 54.1 | 59 | 54.6 | |
| ≥13 | 12 | 6.6 | 6 | 8.1 | 6 | 5.6 | |
| Ambulatory | 172 | 94.5 | 69 | 93.2 | 103 | 95.4 | .536 |
| Cord compression | 19 | 10.4 | 8 | 10.8 | 11 | 10.2 | .892 |
| Neuropathic pain‡ | 96 | 52.7 | 43 | 58.1 | 53 | 49.5 | .230 |
| Paraspinal disease‡ | 61 | 33.5 | 21 | 28.4 | 40 | 37.4 | .224 |
| Epidural involvement§ | 99 | 54.4 | 43 | 68.3 | 56 | 59.6 | .405 |
| Total RT dose (Gy) | |||||||
| Median | 30 | - | 30 | - | 30 | - | - |
| Range | 8-40 | - | 8-40 | - | 8-37.5 | - | - |
| Dose regimens | |||||||
| Single-fraction (8 Gy) | 32 | 17.6 | 18 | 24.3 | 14 | 13.0 | .048 |
| Multifraction‖ | 150 | 82.4 | 56 | 75.7 | 94 | 87.0 | |
| Cumulative BED¶ | |||||||
| 40 Gy | 32 | 17.6 | 18 | 24.3 | 14 | 13 | .197 |
| 41-60 Gy | 29 | 15.9 | 11 | 14.9 | 18 | 16.7 | |
| 61-75 Gy | 94 | 51.6 | 33 | 44.6 | 61 | 56.5 | |
| ≥76 Gy | 27 | 14.8 | 12 | 16.2 | 15 | 13.9 | |
| Number of vertebral bodies covered by RT | |||||||
| 1 | 2 | 1.1 | 0 | 0 | 2 | 1.9 | .525 |
| 2 | 1 | 0.5 | 0 | 0 | 1 | 0.9 | |
| 3 | 43 | 23.6 | 20 | 27 | 23 | 21.3 | |
| 4 | 50 | 27.5 | 20 | 27 | 30 | 27.8 | |
| 5 | 29 | 15.9 | 15 | 20.3 | 14 | 13 | |
| 6 | 19 | 10.4 | 5 | 6.8 | 14 | 13 | |
| 7 | 17 | 9.3 | 5 | 6.8 | 12 | 11.1 | |
| 8 | 10 | 5.5 | 5 | 6.8 | 5 | 4.6 | |
| ≥9 | 11 | 6.0 | 4 | 5.4 | 7 | 6.5 | |
Abbreviations: BED = biological equivalent dose; ECOG PS = Eastern Cooperative Oncology Group Performance Status; RT = radiation therapy; SINS = spinal instability neoplastic score.
Other histology includes: Adrenal (n = 1), carcinoid (n = 2), colon (n = 9), dermatofibroid (n = 1), endometrium/uterine (n = 4), esophagus (n = 14), head and neck (n = 9), leiomyosarcoma (n = 1), liposarcoma (n = 1), meningioma (n = 1), mesothelioma (n = 1), neuroendocrine (n = 2), nuclear protein in testis midline carcinoma (n = 1), pancreas (n = 4), sacromatoid (n = 1), salivary (n = 1), sarcoma (n = 9), skin (n = 3), stomach (n = 2), thyroid (n = 5), and urothelial (n = 9).
Metastatic burden refers to the number of systems with metastatic disease (eg, lung, liver, etc).
Presence of neuropathic pain and paraspinal disease was unknown for 1 patient, who did not experience local failure.
Presence of epidural involvement was unknown for 25 patients, 11 of whom experienced local failure.
Multifraction regimens included 20 Gy in 5 fractions (n = 20), 30 Gy in 10 fractions (n = 95), 35 to 37.5 Gy in 14 to 15 fractions (n = 23), and other radiation therapy regimens (n = 12).
BED refers to the biological equivalent dose of the cumulative dose of RT delivered to the spine