PV QA 1 - Poster Viewing Q&A 1
SU_26_2260 - PSMA-PET-Based Salvage By Image-Guided Adaptive HDR-Brachytherapy (HDR-IGABT) for Locally Relapsed Prostate Cancer or Stereotactic Radiation Therapy (SRT) for Distant Oligometastatic Progression - One-Year Outcomes of a Prospective Assessment in 35 Patien
Sunday, October 21
1:15 PM - 2:45 PM
Location: Innovation Hub, Exhibit Hall 3
PSMA-PET-Based Salvage By Image-Guided Adaptive HDR-Brachytherapy (HDR-IGABT) for Locally Relapsed Prostate Cancer or Stereotactic Radiation Therapy (SRT) for Distant Oligometastatic Progression – One-Year Outcomes of a Prospective Assessment in 35 Patien
R. Galalae1,2, R. Hepp2, C. Morgenstern2, J. P. Exner2, and G. Schabl2; 1Medical Faculty, Christian-Albrechts-University, Kiel, Germany, 2Evangelical Clinics Gelsenkirchen, Radiotherapy Department, Gelsenkirchen, Germany
Purpose/Objective(s): To analyze prospectively outcomes of salvage HDR-IGABT for locally relapsed radioresistent/recurrent prostate cancer (LR-PC) and SRT for oligometastatic prostate cancer disease (OM-PC).
Materials/Methods: PSMA-PET was used to detect LR-PC and/or OM-PC in patients with rising PSA values following pre-irradiation or radical prostatectomy (RPE). Thirty-five patients were included with detection of 20 local relapses (5 patients after RPE without irradiation, 10 patients externally pre-irradiated with a mean dose of 69 Gy, and 5 patients following HDR monotherapy pre-treated with 3 x 11.5 Gy), 8 patients with OM-PC (6 externally pre-irradiated with a mean dose of 67.15 Gy), and 7 patients without any PSMA-radioligands accumulation. Thus, the detection rate was 80%. Eligible for this analysis were 18 patients with LR-PC irradiated with a salvage HDR-protocol of 3 x 9 Gy (EQD2 alpha/beta 3 >100 Gy), and 7 patients with OM-PC treated with SRT (EQD2 alpha/beta 3 >70 Gy) with a follow-up (FU) >3 months. The acute/chronic toxicity was assessed according to CTCAE classification. The biochemical control was measured by repetitive PSA measurements along with clinical examination incl. ultrasound. In recurrently rising values a new PSMA-PET was performed.
Results: Mean FU was 10 months (3-26 months). Mean iPSA pre-salvage was 3.68 ng/ml. Mean one-year post-salvage PSA was 0.9 ng/ml (local salvage), and 0.05 ng/ml (SRT). The one-year overall and cancer specific survival was 100% for the entire cohort. The one-year biochemical control (BC) according ASTRO/Phoenix definitions was 81.25% for the local salvage and 71.4% for the SRT treatments, respectively. The one-year disease-free survival (DFS) was 88% for the local salvage and 71.4% for the SRT treatments, respectively. In general, the observed acute/chronic toxicity was very low. Local salvage acute toxicity grade 1-2 haematuria/cystitis occurred in weeks 2-4 only, and one patient developed a grade 2-obstruction in week 5. One patient was treated with TURP for grade 3 obstruction at 20 months. Acute/chronic gastrointestinal toxicity was insignificant (one grade 2 proctitis at 6 months). Rectal spacers were implanted prior intervention in 7 patients with local salvage. One patient developed pronounced fatigue. SRT-toxicity was insignificant as well (two patients with fatigue and one patient with grade 3 proctitis in week 3).
Conclusion: The one-year outcomes of PSMA-PET based salvage brachytherapy for locally relapsed radioresistent/recurrent prostate cancer and stereotactic radiotherapy for oligometastatic prostate cancer disease were very promising with very low prospectively measured acute/chronic CTCAE toxicity profiles. Table 1: One-year results for PSMA-PET based salvage HDR-IGABT in locally relapsed prostate cancer and SRT in oligometastatic prostate cancer
| RT Method (N) ||Indication ||1-Y OS ||1-Y CSS ||1-Y BC || 1 Y-DFS |
| HDR-IGABT (N=18) ||Local relapse ||100% ||100% ||81.25% || 88% |
| SRT (N=7) || Oligometastatic disease ||100% ||100% ||71.4% ||71.4% |
Author Disclosure: R. Galalae: None. R. Hepp: None. C. Morgenstern: None. J. Exner: None. G. Schabl: None.