Table 1.
SpaceOAR vs. no SpaceOAR, continuous variables
| Continuous variable | No SpaceOAR (n = 174) | SpaceOAR (n = 174) | p-value† | Total pts. (N = 348) | |||||
|---|---|---|---|---|---|---|---|---|---|
| Mean | SD | Median | Mean | SD | Median | Mean | SD | ||
| Age at implant (years) | 64.8 | (6.7) | 64.3 | 64.8 | (7.4) | 65.2 | 0.914 | 64.8 | (7.0) |
| Pre-Tx PSA (ng/ml) | 10.6 | (13.9) | 6.7 | 9.5 | (8.9) | 6.8 | 0.367 | 10.1 | (11.6) |
| Gleason score | 7.3 | (0.6) | 7.0 | 7.5 | (0.8) | 7.0 | 0.005 | 7.4 | (0.7) |
| TRUS prostate volume (cm3) | 23.4 | (6.1) | 23.4 | 23.1 | (6.0) | 23.2 | 0.625 | 23.3 | (6.0) |
| Planning target volume, PTV (cm3) | 48.0 | (9.8) | 47.3 | 48.2 | (10.0) | 48.4 | 0.834 | 48.1 | (9.9) |
| Post-implant CT volume (cm3) | 64.3 | (12.3) | 63.2 | 65.9 | (11.9) | 64.9 | 0.221 | 65.1 | (12.1) |
| Plan vol. of Rx isodose (cm3) | 85.3 | (15.7) | 83.7 | 87.7 | (15.8) | 87.3 | 0.159 | 86.5 | (15.8) |
| CT vol. of Rx isodose (cm3) | 97.8 | (6.9) | 98.2 | 99.4 | (14.8) | 99.0 | 0.216 | 98.6 | (11.5) |
| Number of seeds | 104.3 | (11.3) | 103.0 | 106.0 | (11.6) | 105.5 | 0.185 | 105.2 | (11.5) |
| Seed strength (U) | 2.55 | (0.48) | 2.32 | 2.41 | (0.40) | 2.23 | 0.004 | 2.48 | (0.45) |
| Body mass index (kg/m2) | 30.0 | (5.5) | 29.3 | 30.5 | (6.0) | 29.6 | 0.372 | 30.2 | (5.8) |
| PTV D90 (%) | 123.4 | (8.7) | 122.6 | 121.1 | (10.0) | 119.9 | 0.025 | 122.2 | (9.4) |
| PTV V100 (%) | 97.9 | (1.5) | 98.3 | 97.7 | (1.8) | 98.3 | 0.254 | 97.8 | (1.6) |
| PTV V150 (%) | 73.3 | (6.6) | 73.0 | 72.0 | (7.3) | 72.0 | 0.070 | 72.7 | (7.0) |
| PTV V200 (%) | 44.9 | (6.1) | 44.3 | 44.6 | (6.9) | 43.6 | 0.671 | 44.7 | (6.5) |
| Prostatic urethral dose (%) | 112.9 | (12.2) | 111.9 | 111.8 | (12.0) | 109.8 | 0.397 | 112.4 | (12.1) |
| Prostatic urethral dose, max. (%) | 130.5 | (17.2) | 129.5 | 127.2 | (19.0) | 123.2 | 0.096 | 128.9 | (18.2) |
| Bulbomembranous dose (Gy) | 33.0 | (12.4) | 31.4 | 34.6 | (14.3) | 31.2 | 0.288 | 33.8 | (13.4) |
| Rectal dose (%) | 34.2 | (15.4) | 32.3 | 22.8 | (8.5) | 20.8 | < 0.001 | 28.5 | (13.7) |
| Rectal dose, max. (%) | 51.8 | (23.0) | 47.9 | 32.6 | (12.0) | 30.4 | < 0.001 | 42.2 | (20.7) |
| Rectum V110 (cm3) | 0.009 | (0.033) | 0.0 | 0.008 | (0.086) | 0.0 | 0.869 | 0.009 | (0.065) |
| Rectal wall V50 (cm3) | 1.90 | (1.07) | 1.88 | 0.58 | (0.77) | 0.21 | < 0.001 | 1.90 | (1.07) |
†
Two sample t-test, p-values ≤ 0.5 in bold, PTV – planned target volume, D90 – minimum dose to the hottest 90% of the volume as percentage of the prescribed (Rx) dose, Vpd – volume receiving pd percent of the prescribed PTV dose as percentage of the structure volume or cm3, as specified