Table 1.
Baseline patient-, tumour-, and treatment-related characteristics.
| Characteristic | Missing (%) | ||
|---|---|---|---|
| Primary treatment | |||
| Primary treatment, n (%) | 0 | ||
| EBRT | 80 (53.3) | ||
| LDR brachytherapy | 67 (44.7) | ||
| HDR brachytherapy | 3 (2) | ||
| EBRT dose (Gy), median (IQR) | 76.0 (71.5–77.0) | 12.5 | |
| LDR dose (Gy), median (IQR) | 145.0 (145.0–145.0) | 0 | |
| HDR dose (Gy), median (IQR) | 19.0 (19.0–38.0) | 0 | |
| PLND at primary treatment, n (%) | 30 (20.0) | 0 | |
| Initial NCCN risk group, n (%) | 5.4 | ||
| Low risk | 27 (18.0) | ||
| Intermediate risk | 56 (37.3) | ||
| High risk | 59 (39.3) | ||
| ADT use (adjuvant/neoadjuvant), n (%) | 30 (20.0) | 0 | |
| ADT duration (mos.), median (IQR) (n = 30) | 36.0 (18.0–36.0) | 10 | |
| PSA nadir post-primary treatment (ng/mL), median (IQR) | 0.56 (0.25–1.10) | 3.3 | |
| FS-HDR-BT | |||
| Pre-salvage PSADT (months), median (IQR) | 15.7 (11.6–23.6) | 0 | |
| Interval between primary and salvage treatment (months), median (IQR) | 97 (63–128) | 0 | |
| Age at FS-HDR-BT (years), mean (±SD) | 71.5 (±5.0) | 0 | |
| Pre-salvage PSA (ng/mL), median (IQR) | 4.88 (2.80–6.80) | 0 | |
| Imaging T-stage at FS-HDR-BT, n (%) | 0 | ||
| T1-2a | 45 (30.0) | ||
| T2b-2c | 40 (26.7) | ||
| T3a-3b | 63 (42.0) | ||
| T4 | 2 (1.3) | ||
| Gleason at FS-HDR-BT, n (%) | 45.4 | ||
| 3 + 3 = 6 | 14 (9.3) | ||
| 3 + 4 = 7 | 27 (18.0) | ||
| 4 + 3 = 7 | 21 (14.0) | ||
| Sum score = 8 | 6 (4.0) | ||
| Sum score = 9/10 | 14 (9.3) | ||
| Tumour location, n (%) | 0 | ||
| Base | 21 (14.0) | ||
| Midgland | 29 (19.3) | ||
| Apex | 21 (14.0) | ||
| Combination base/midgland/apex | 31 (20.7) | ||
| Seminal vesicle | 23 (15.3) | ||
| Prostate body and seminal vesicle | 25 (16.7) | ||
| Seminal vesicle involvement at FS-HDR-BT, n (%) | 48 (32.0) | 0 | |
| GTV at FS-HDR-BT (cm3), median (IQR) | 3.0 (1.7–5.1) | 0.7 | |
| CTV at FS-HDR-BT (cm3), median (IQR) | 8.5 (6.0–12.8) | 0 | |
| Prostate volume at FS-HDR-BT (cm3), median (IQR) | 31.4 (25.7–39.6) | 0 | |
| D95% CTV (Gy), median (IQR) | 18.8 (17.4–19.7) | 0 | |
| V200% CTV (%), median (IQR) | 26.3 (18.4–27.9) | 0 | |
| Post-salvage PSA nadir (ng/mL), median (IQR) | 0.76 (0.26–1.30) | 0 | |
| Post-salvage time to PSA nadir (months), median (IQR) | 6.1 (3.6–9.6) | 0 | |
| Percentage PSA reduction (%), median (IQR) | 84.2 (68.3–92.9) | 0 | |
| Biochemical recurrence, n (%) | 61 (40.7) | 0 | |
| Follow-up time (months), median (IQR) | 25.1 (13.5–36.1) | 0 | |
Abbreviations: IQR = interquartile range. SD = standard deviation. EBRT = external beam radiotherapy. LDR = low-dose rate. HDR = high-dose rate. PLND = pelvic lymph node dissection. NCCN = national comprehensive cancer network. ADT = androgen deprivation therapy. PSA = prostate specific antigen. FS-HDR-BT = focal salvage high-dose-rate brachytherapy. PSADT = PSA doubling time. GTV = gross tumour volume. D95% = dose to 95% of the volume. V200% = volume receiving 200% or more of the prescribed dose. CTV = clinical target volume.