Table 4.
Baseline Demographic Characteristics for the IMRT vs Proton Therapy Comparison
| No. (%) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Before Propensity Matching | After Propensity Matching | |||||||
| Characteristics | IMRT (n = 9437) |
Proton (n = 685) |
P Value |
IMRT (n = 684) |
Proton (n = 684) |
P Value |
||
| Year of radiation | ||||||||
| 2002 | 448 (4.8) | 119 (17.4) |  |
<.001 | 110 (16.1) | 118 (17.3) | |
.34 |
| 2003 | 917 (9.7) | 127 (18.5) | 131 (19.2) | 127 (18.6) | ||||
| 2004 | 1334 (14.1) | 122 (17.8) | 122 (17.8) | 122 (17.8) | ||||
| 2005 | 1841 (19.5) | 102 (14.9) | 79 (11.6) | 102 (14.9) | ||||
| 2006 | 2226 (23.6) | 97 (14.2) | 99 (14.5) | 97 (14.2) | ||||
| 2007 | 2671 (28.3) | 118 (17.2) | 143 (20.9) | 118 (17.3) | ||||
| Age at diagnosis, y | ||||||||
| 66–69 | 1924 (20.4) | 248 (36.2) |  |
<.001 | 244 (35.7) | 247 (36.1) | |
.61 |
| 70–74 | 3366 (35.7) | 233 (34.0) | 249 (36.4) | 233 (34.1) | ||||
| ≥75 | 4147 (43.9) | 204 (29.8) | 191 (27.9) | 204 (29.8) | ||||
| Race | ||||||||
| White | 7991 (84.7) | 634 (92.6) | |
<.001 | 635 (92.8) | 633 (92.5) | |
.77 |
| Black | 772 (8.2) | 20 (2.9) | 16 (2.3) | 20 (2.9) | ||||
| Other/unknown | 674 (7.1) | 31 (4.5) | 33 (4.8) | 31 (4.5) | ||||
| SEER region | ||||||||
| Atlanta and rural Georgia | 161 (1.7) | <11 (<2.0) |  |
<.001 | <11 (<2.0) | <11 (<2.0) | |
.83 |
| California | 2928 (31.0) | 546 (79.7) | 560 (81.9) | 546 (79.8) | ||||
| Connecticut | 921 (9.8) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| Detroit | 619 (6.6) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| Hawaii | 230 (2.4) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| Iowa | 526 (5.6) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| Kentucky | 510 (5.4) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| Louisiana | 662 (7.0) | <11 (<2.0) | 13 (1.9) | <11 (<2.0) | ||||
| New Jersey | 2134 (22.6) | <11 (<2.0) | <11 (<2.0) | <11 (<2.0) | ||||
| New Mexico | 381 (4.0) | 26 (3.8) | 19 (2.8) | 26 (3.8) | ||||
| Seattle | 306 (3.2) | 42 (6.1) | 32 (4.7) | 42 (6.1) | ||||
| Utah | 59 (0.6) | 22 (3.2) | 22 (3.2) | 21 (3.1) | ||||
| Marital status | ||||||||
| Married | 6657 (70.5) | 530 (77.4) | |
<.001 | 539 (78.8) | 529 (77.3) | |
.70 |
| Not married | 1866 (19.8) | 109 (15.9) | 106 (15.5) | 109 (15.9) | ||||
| Missing/unknown | 914 (9.7) | 46 (6.7) | 39 (5.7) | 46 (6.7) | ||||
| Census income | ||||||||
| (%) Low income (0–25) | 2213 (23.5) | 175 (25.5) |  |
.004 | 128 (18.7) | 131 (19.2) | |
.84 |
| Low-medium income (26–50) | 2324 (24.6) | 177 (25.8) | 211 (30.9) | 211 (30.9) | ||||
| Medium-high income (51–75) | 2399 (25.4) | 195 (28.5) | 180 (26.3) | 190 (27.8) | ||||
| High income (>75) | 2501 (26.5) | 138 (20.2) | 165 (24.1) | 152 (22.2) | ||||
| Census proportion with at least high school education (%) |
||||||||
| Low education (0–25) | 2074 (22.0) | 131 (19.1) | |
<.001 | 163 (23.8) | 175 (25.6) | |
.50 |
| Low-medium education (26–50) | 2240 (23.7) | 211 (30.8) | 189 (27.6) | 177 (25.9) | ||||
| Medium-high education (51–75) | 2525 (26.8) | 191 (27.9) | 179 (26.2) | 195 (28.5) | ||||
| High education (>75) | 2598 (27.5) | 152 (22.2) | 153 (22.4) | 137 (20.0) | ||||
| Population density | ||||||||
| Metropolitan | 8091 (85.7) | 617 (90.1) |  |
.002 | 72 (10.5) | 68 (9.9) | |
.72 |
| Nonmetropolitan | 1346 (14.3) | 68 (9.9) | 612 (89.5) | 616 (90.1) | ||||
Abbreviations: IMRT, intensity-modulated radiation therapy; SEER, Surveillance, Epidemiology, and End Results.