Table 1.
Baseline characteristics according to the radiotherapy dose of patients with bone metastases from solid tumors in the cohort study and after propensity score matching
| Entire cohort (n = 1795) | Propensity score matching (n = 1340) | |||||
|---|---|---|---|---|---|---|
| Standard‐dose RT n = 1125 (63%) | Dose‐escalated RT n = 670 (50%) | P | Standard‐dose RT n = 670 (50%) | Dose‐escalated RT n = 670 (50%) | P | |
| EQD2Gy | ||||||
| Mean±SD | 32.5 ± 0 | 40.4 ± 7.5 | <0.001 | 32.5 ± 0 | 40.4 ± 7.5 | <0.001 |
| Median (range) | 32.5 (0) | 38.1 (32.6–73.2) | 32.5 (0) | 38.1 (32.6–73.2) | ||
| Dose per fraction (cGy) | ||||||
| Mean±SD | 300 ± 0 | 317.13 ± 104.9 | <0.001 | 300 ± 0 | 317.13 ± 104.9 | <0.001 |
| Median (range) | 300 | 300 (167–800) | 300 | 300 (167–800) | ||
| RT duration (days) | ||||||
| Mean±SD | 14.3 ± 2.9 | 19.6 ± 9.3 | <0.001 | 14.4 ± 3.3 | 19.6 ± 9.3 | <0.001 |
| Age (years) | ||||||
| Mean±SD | 62.4 ± 12.6 | 59.6 ± 12.9 | <0.001 | 59.7 ± 12.0 | 59.6 ± 12.9 | 0.771 |
| <60, n (%) | 454 (40.4) | 340 (50.8) | <0.001 | 332 (49.5) | 340 (50.8) | 0.672 |
| ≥60, n (%) | 671 (59.6) | 330 (49.2) | 338 (50.4) | 330 (49.2) | ||
| Symptoms | ||||||
| Absence of symptoms, n (%) | 72 (6.4) | 61 (9.0) | 0.013 | 72 (10.7) | 61 (9.0) | 0.776 |
| Pain, n (%) | 735 (65.3) | 469 (70) | 467 (69.8) | 469 (70) | ||
| Neurological deficits, n (%) | 318 (28.3) | 141 (21.0) | 131 (19.5) | 141 (21.0) | ||
| Time to metastases (years) | ||||||
| Mean±SD | 1.06 ± 2.2 | 1.58 ± 2.7 | <0.001 | 1.62 ± 2.7 | 1.58 ± 2.7 | 0.388 |
| <1 year, n (%) | 842 (74.8) | 418 (62.4) | <0.001 | 413 (61.8) | 418 (62.4) | 0.803 |
| ≥1 year, n (%) | 283 (25.2) | 252 (37.6) | 257 (38.2) | 252 (37.6) | ||
| Sex | ||||||
| Male, n (%) | 475 (42.2) | 300 (44.8) | 0.343 | 289 (43.1) | 300 (44.8) | 0.337 |
| Female, n (%) | 650 (57.8) | 370 (55.2) | 381 (56.9) | 370 (55.2) | ||
| Performance status | ||||||
| ECOG 0–1, n (%) | 515 (45.8) | 354 (52.8) | 0.002 | 352 (52.4) | 354 (52.8) | 0.878 |
| ECOG 2–4, n (%) | 610 (54.2) | 316 (47.2) | 318 (47.6) | 316 (47.2) | ||
| Site of bone metastases | ||||||
| Spinal lesions, n (%) | 863 (76.7) | 368 (54.9) | <0.001 | 408 (60.8) | 368 (54.9) | 0.031 |
| Nonspinal lesions, n (%) | 262 (23.3) | 302 (45.1) | 262 (39.2) | 302 (45.1) | ||
| Metastases to >1 site | ||||||
| No, n (%) | 270 (24) | 168 (25.2) | 0.518 | 169 (25.2) | 168 (25.2) | 0.903 |
| Yes, n (%) | 855 (76) | 502 (74.8) | 501 (74.8) | 502 (74.8) | ||
| Location of primary cancer | ||||||
| Lung, n (%) | 443 (39.5) | 164 (24.5) | <0.001 | 156 (23.3) | 164 (24.5) | 0.372 |
| Urinary tract, n (%) | 193 (17.2) | 103 (15.4) | 100 (14.9) | 103 (15.4) | ||
| Breast, n (%) | 122 (10.8) | 120 (17.9) | 115 (17.1) | 120 (17.9) | ||
| Other primary cancer location, n (%) | 367 (32.6) | 283 (42.2) | 309 (44.7) | 283 (42.2) | ||
| Systemic therapy | ||||||
| No, n (%) | 642 (57.1) | 355 (52.9) | 349 (52.1) | 355 (52.9) | 0.836 | |
| Yes, n (%) | 483 (42.9) | 315 (47.1) | 0.132 | 321 (47.9) | 315 (47.1) | |
| Comorbidities | ||||||
| No, n (%) | 699 (62.1) | 396 (59) | 403 (60.1) | 396 (59) | 0.798 | |
| Yes, n (%) | 426 (37.9) | 274 (41) | 0.284 | 267 (39.9) | 274 (41) | |
| Employment status | ||||||
| High‐wage employed, n (%) | 233 (20.7) | 154 (23.0) | 150 (22.4) | 154 (23.0) | 0.821 | |
| Low‐wage employed, n (%) | 360 (32) | 193 (28.8) | 0.299 | 205 (30.6) | 193 (28.8) | |
| Unemployed, n (%) | 532 (47.3) | 323 (48.2) | 315 (47.0) | 323 (48.2) | ||
| Education level | ||||||
| None/primary | 674 (59.9%) | 347 (51.7%) | 334 (49.9%) | 347 (51.7%) | 0.531 | |
| Higher | 451 (40.1%) | 323 (48.3%) | 0.002 | 336 (50.1%) | 323 (48.3%) | |
| Place of residence | ||||||
| Urban, n (%) | 651 (57.8) | 382 (57.1) | 391 (58.2) | 382 (57.1) | 0.648 | |
| Rural, n (%) | 474 (42.2) | 288 (42.9) | 0.912 | 279 (41.8) | 288 (42.9) | |
| Cigarette smoking | ||||||
| No, n (%) | 675 (60) | 401 (59.9) | 385 (57.4) | 401 (59.9) | 0.442 | |
| Yes, n (%) | 450 (40) | 269 (40.1) | 0.849 | 285 (42.6) | 269 (40.1) | |
| Betel quid chewing | ||||||
| No, n (%) | 1008 (89.6) | 584 (87.2) | 569 (84.9) | 584 (87.2) | 0.401 | |
| Yes, n (%) | 117 (10.4) | 86 (12.8) | 0.322 | 101 (15.1) | 86 (12.8) | |
| Alcohol drinking | ||||||
| No, n (%) | 864 (76.8) | 494 (73.8) | 477 (71.2) | 494 (73.8) | 0.291 | |
| Yes, n (%) | 261 (23.2) | 176 (26.2) | 0.127 | 193 (28.8) | 176 (26.2) | |
| Propensity score | ||||||
| Mean±SD | 0.672 ± 0.146 | 0.586 ± 0.157 | <0.00 | 0.599 ± 0.115 | 0.586 ± 0.157 | 0.264 |
| OS, months | ||||||
| Median (range) | 5.75 (5.17–6.34) | 8.48 (7.16–9.80) | <0.0010 | 6.27 (5.39–7.36) | 8.48 (7.16–9.80) | <0.0010 |
| 1‐year OS rate, % | 30.4 | 40.7 | <0.00 | 34.2 | 40.7 | <0.00 |
| 2‐year OS rate, % | 16.0 | 23.7 | 19.1 | 23.7 | ||
| Local control, months | ||||||
| 1‐year LC rate, % | 96.7 | 98.3 | 0.007 | |||
| 2‐year LC rate, % | 90.3 | 95.2 | 0.014 | |||
| 4‐year LC rate, % | 81.5 | 86.4 | 0.031 | |||
LC, Local control; OS, overall survival; RT, radiotherapy.