Table 4.
Patients who received no SpaceOAR (reference group) compared to those who received SpaceOAR prior to any radiation therapy and compared to those who received SpaceOAR on the day of brachytherapy seed implant
| Continuous variable | No SpaceOAR (n = 174) |
SpaceOAR before XRT (n = 83) |
SpaceOAR at brachy (n = 91) |
p-value† | p-value‡ | |||
|---|---|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | Mean | SD | |||
| TRUS prostate volume (cm3) | 23.4 | (6.1) | 22.7 | (6.3) | 23.5 | (5.7) | 0.362 | 0.919 |
| Planning target volume, PTV (cm3) | 48.0 | (9.8) | 48.0 | (10.5) | 48.3 | (9.6) | 0.970 | 0.763 |
| PTV D90 (%) | 123.4 | (8.7) | 123.3 | (10.7) | 119.1 | (9.0) | 0.973 | < 0.001 |
| PTV V100 (%) | 97.9 | (1.5) | 98.0 | (1.6) | 97.4 | (1.9) | 0.563 | 0.020 |
| PTV V150 (%) | 73.3 | (6.6) | 73.4 | (7.1) | 70.7 | (7.2) | 0.910 | 0.003 |
| PTV V200 (%) | 44.9 | (6.1) | 46.1 | (7.1) | 43.2 | (6.5) | 0.148 | 0.036 |
| Prostatic urethral dose (%) | 112.9 | (12.2) | 115.4 | (14.1) | 108.5 | (8.5) | 0.141 | 0.002 |
| Prostatic urethral dose, max. (%) | 130.5 | (17.2) | 132.8 | (22.1) | 122.2 | (14.0) | 0.359 | < 0.001 |
| Bulbomembranous dose (Gy) | 33.0 | (12.4) | 34.9 | (12.7) | 34.3 | (15.8) | 0.264 | 0.492 |
| Rectal dose (%) | 34.2 | (15.4) | 23.8 | (8.5) | 21.8 | (8.5) | < 0.001 | < 0.001 |
| Rectal dose, max. (%) | 51.8 | (23.0) | 33.9 | (12.5) | 31.4 | (11.5) | < 0.001 | < 0.001 |
| Rectum V110 (cm3) | 0.009 | (0.033) | 0.002 | (0.016) | 0.014 | (0.118) | 0.050 | 0.624 |
| Rectal wall V50 (cm3) | 1.90 | (1.07) | 0.596 | (0.801) | 0.571 | (0.754) | < 0.001 | < 0.001 |
†
Two sample t-test comparing No SpaceOAR with SpaceOAR before XRT, p-values ≤ 0.5 in bold, ‡two sample t-test comparing No SpaceOAR with SpaceOAR at brachytherapy, p-values ≤ 0.5 in bold