Table 2.
Distribution of patients, tumors, and treatment factors for proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) in patients matched by propensity score (n = 220).a
|
Characteristic |
IMRT (n = 110) |
PBT (n = 110) |
P
value |
| Age (y), at diagnosis, mean, median (minimum-maximum) | 69, 69 (44-84) | 69, 70 (41-86) | .93 |
| PTV (cm3), mean, median (minimum-maximum) | 546, 508 (96-1570) | 534, 510 (104-1303) | .88 |
| Sex, No. (%) | .23 | ||
| Female | 25 (22.7) | 18 (16.4) | |
| Male | 85 (77.3) | 92 (93.6) | |
| Stage, No. (%) | .98 | ||
| I | 6 (5.5) | 4 (3.6) | |
| IIA | 34 (30.9) | 35 (31.8) | |
| IIB | 4 (3.6) | 4 (3.6) | |
| III | 62 (56.4) | 64 (58.2) | |
| IVA | 4 (3.6) | 3 (2.7) | |
| KPS, No. (%) | .82 | ||
| 70 | 11 (10) | 10 (9.1) | |
| 80-100 | 99 (90) | 100 (90.9) | |
| Tumor location in esophagus, No. (%) | 1.00 | ||
| Upper and middle | 26 (23.6) | 26 (23.6) | |
| Lower | 84 (76.4) | 84 (76.4) | |
| Induction chemotherapy, No. (%) | .88 | ||
| No | 79 (71.8) | 80 (72.7) | |
| Yes | 31 (28.2) | 30 (27.3) | |
| Histology, No. (%) | .44 | ||
| Adenocarcinoma | 84 (76.4) | 79 (71.8) | |
| Squamous cell carcinoma | 26 (23.6) | 31 (28.2) |
Abbreviations: PTV, planning treatment volume; KPS, Karnofsky performance status.
a
To calculate the propensity score, age, log (PTV), clinical stage, KPS, and tumor location were included.