Table 1.
Cohort Characteristics. Characteristics of patients With CNS Malignancies Receiving Either Photon or Proton Radiotherapy. P Values from Chi-Square Test
| Characteristic | Photon (n = 74 787) | Proton (n = 1 370) | P | ||
|---|---|---|---|---|---|
| No. | % | No. | % | ||
| Year of diagnosis (median, IQR) | 2010 | 2007-2013 | 2013 | 2011-2014 | < .001 |
| Age, mean, SD, y | 54.71 | 17.71 | 29.86 | 22.85 | < .001 |
| Sex (n, %) | .552 | ||||
| Male | 42 607 | 57 | 769 | 56.1 | |
| Female | 32 180 | 43 | 601 | 43.9 | |
| Race (n, %) | < .001 | ||||
| White | 66 155 | 88.5 | 1155 | 84.3 | |
| Black | 53 16 | 7.1 | 71 | 5.2 | |
| Other | 3316 | 4.4 | 144 | 10.5 | |
| Charlson Comorbidity score (n, %) | < .001 | ||||
| 0 | 57 722 | 77.2 | 1207 | 88.1 | |
| 1 | 10 960 | 14.7 | 118 | 8.6 | |
| 2+ | 6105 | 8.2 | 45 | 3.3 | |
| Insurance status (n, %) | < .001 | ||||
| No insurance | 3060 | 4.1 | 29 | 2.1 | |
| Medicaid | 6683 | 8.9 | 207 | 15.1 | |
| Medicare | 22 221 | 29.7 | 135 | 9.9 | |
| Private insurance | 40 530 | 54.2 | 945 | 69 | |
| Unknown | 2293 | 3.1 | 54 | 3.9 | |
| Income (n, %), $ | < .001 | ||||
| < 38 000 | 1201 | 1.6 | 14 | 1 | |
| 38 000-47 999 | 10 686 | 14.3 | 126 | 9.2 | |
| 48 000-62 999 | 16 379 | 21.9 | 226 | 16.5 | |
| > 63 000 | 20 460 | 27.4 | 362 | 26.4 | |
| Unknown | 26 061 | 34.8 | 642 | 46.9 | |
| Region (n, %)a | < .001 | ||||
| Mountain | 3123 | 4.2 | 5 | 0.4 | |
| North Atlantic | 13 978 | 18.7 | 115 | 8.4 | |
| North Central | 17 038 | 22.8 | 97 | 7.1 | |
| Pacific | 7355 | 9.8 | 188 | 13.7 | |
| South Atlantic | 12 146 | 16.2 | 27 | 2 | |
| South Central | 7961 | 10.6 | 50 | 3.6 | |
| Unknown | 13 186 | 17.6 | 888 | 64.8 | |
| Tumor histology (n, %) | < .001 | ||||
| Embryonal | 2536 | 3.4 | 327 | 23.9 | |
| Ependymal | 2161 | 2.9 | 198 | 14.5 | |
| Germ cell | 367 | 0.5 | 33 | 2.4 | |
| Glial | 61 318 | 82 | 526 | 38.4 | |
| Meningeal | 4376 | 5.9 | 128 | 9.3 | |
| Other | 4029 | 5.4 | 158 | 11.5 | |
| WHO grade (n, %) | < .001 | ||||
| I | 2167 | 2.9 | 93 | 6.8 | |
| II | 6781 | 9.1 | 255 | 18.6 | |
| III | 9808 | 13.1 | 265 | 19.3 | |
| IV | 49 259 | 65.9 | 463 | 33.8 | |
| Unknown | 6772 | 9.1 | 294 | 21.5 | |
| Resection extent (n, %) | < .001 | ||||
| Biopsy | 9270 | 12.4 | 224 | 16.4 | |
| GTR | 14 175 | 19 | 494 | 36.1 | |
| STR | 13 594 | 18.2 | 307 | 22.4 | |
| Other/Unknown | 37 748 | 50.5 | 345 | 25.2 | |
| Academic facility (n, %)a | < .001 | ||||
| Yes | 12 146 | 19.7 | 27 | 5.6 | |
| No | 25 634 | 41.6 | 182 | 37.8 | |
| Unknown | 23 821 | 38.7 | 273 | 56.6 | |
| Time to treatment initiation, d | |||||
| Pediatric (median, IQR) | |||||
| Embryonal | 30 | 27 to 40 | 33 | 28 to 69 | < .001 |
| Ependymal | 41 | 32 to 60 | 48 | 38 to 67 | < .001 |
| Germ cell | 104 | 36 to 139 | 122 | 111 to 157 | .482 |
| Glial | 30 | 22 to 42 | 42 | 29 to 69 | < .001 |
| Meningeal | 57 | 45 to 94 | 59 | 36 to 63 | .584 |
| Other | 52 | 32 to 95 | 80 | 56 to 125 | < .001 |
| Adult (median, IQR) | |||||
| Embryonal | 41 | 31 to 55 | 43 | 32 to 57 | .770 |
| Ependymal | 54 | 37 to 80 | 74 | 50 to 112 | < .001 |
| Germ cell | 56 | 30 to 127 | 100 | 45 to 146 | .083 |
| Glial | 31 | 24 to 40 | 45 | 34 to 66 | < .001 |
| Meningeal | 64 | 43 to 104 | 99 | 69 to 149 | < .001 |
| Other | 68 | 39 to 119 | 97 | 70 to 136 | < .001 |
Abbreviations: GTR, gross total resection; IQR, interquartile range; STR, subtotal resection; WHO, World Health Organization.
Bold P values indicate statistical significance (p < 0.05).
aFacility type available only for patients age 40 or older.