3249 - Low-Dose-Rate Brachytherapy for Focal Salvage of Prostate Cancer Local Recurrence Using Scintigraphic Guidance
Presenter(s)
J. P. Ciezki1, C. A. Reddy2, M. D. Kolar1, K. Angermeier3, A. Altman3, P. Bajic4, R. Bole4, F. Secin4, and S. Campbell5; 1Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH, 2Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, OH, 3Glickman Urologic and Kidney Institute, Cleveland Clinic Foundation, Cleveland, OH, 4Cleveland Clinic, Cleveland, OH, 5West Virginia University Department of Urology, Morgantown, WV
Purpose/Objective(s): Report the early efficacy and toxicity of focal salvage with low-dose-rate brachytherapy (LDR) using scintigraphic localization after definitive radiotherapy, HIFU, or cryotherapy.
Materials/Methods: The records of 105 patients (initial treatments: LDR -54, external beam radiation (EBRT) – 40, EBRT + LDR – 5, Cryotherapy – 3, EBRT + high-dose-rate brachytherapy (HDR) – 1, HIFU – 1, proton beam -1) who received focal salvage LDR were reviewed. There were 77.1 % of patients who had biochemical failure according to the nadir + 2 ng/mL definition, but all had scintigraphic evidence of local recurrence. The LDR was guided by scintigraphic documentation of avidity in the prostate or seminal vesicle. A dose of 144 Gy was prescribed with I-125. A margin of 0.5 cm was given except when adjacent to bladder, urethra, or rectum in which case no margin was given with any of those structures. The efficacy was assessed by PSA readings and imaging. Toxicity was assessed by CTCAE v6.0.
Results: The median follow-up was 22.3 months (m) (range: 1.1 -67.9). At last follow-up, 83 (79%) were without evidence of disease (NED). One patient is dead of disease. Pre-salvage biopsies were obtained on 37 (35.2%) of patients. The driver of focal salvage LDR was scintigraphically defined with not all patients having a biochemical failure prior to clinical failure (cF) treated with focal salvage LDR. On univariable analysis of cF after focal slavage LDR, longer time to local failure (p=0.0231, HR: 0.981-0.999) and seminal vesicle treatment (p=0.0272. HR: 1.119-6.536) were significant. No variable was significant on multivariable analysis. Neither initial therapy type nor having had a biopsy to confirm local failure had any effect on outcome. Toxicity is reported in the table.
Conclusion: Using scintigraphic localization to target LDR is a safe and effective means to achieve local control for prostate cancer recurrence.
| Toxicity Change Over Time | ||
| Toxicity (grade) | Pre-Salvage (number of patients) | Last Follow-up (number of patients) |
| GU Toxicity | ||
| 0 | 55 | 43 |
| 1 | 28 | 38 |
| 2 | 16 | 17 |
| 3 | 6 | 7 |
| GI Toxicity | ||
| 0 | 100 | 101 |
| 1 | 4 | 2 |
| 2 | 0 | 2 |
| 3 | 1 | 0 |