ESTRO 2024 - Abstract Book

S2613

Clinical - Urology

ESTRO 2024

Results:

84 pts with BCR following RP (72 pN0, 12 pNx) plus P-bed RT and staged with PSMA-PET (between June 2016 and October 2020) were included in the present analysis. Median follow-up from PSMA-PET was 48.7 months. Overall, 14 pts had received ADT along with the previous P-bed RT. P-bed RT was performed as adjuvant RT (ART) in 27 pts. The remaining 57 pts had received salvage RT (SRT), with a median pre-treatment PSA of 0,47 ng/ml. The median interval from the end of the previous P-bed RT to BCR was 35,1 months. Median PSA at PSMA-PET was 0,58 ng/ml. PSMA-PET was positive in 45 patients (53.6%) with a total of 74 lesions detected. The median number of lesions per positive PSMA-PET was 3 (2-4) in 16/45 patients; the remaining 29/45 pts had a single relapse site. Positive regional nodes were detected for 22/45 pts. Positive distant nodes were detected for 3/45 pts. Positive bone mets were detected in 9/45. In 2/45 pts a visceral met (lung) was detected. Eight pts had multiple different sites of PSMA-PET positivity. Only 1/45 had a PSMA uptake exclusively within the P-bed. Positive PSMA-PET tailored treatments were: ADT for 17 pts (37.8%), SBRT (n = 9) or Salvage-Pelvic Lymph Node Dissection (S-PLND, n = 2) for 11 pts (24.4%), and SBRT/S-PLND + ADT for 17 pts (37.8%). Figure 1 depicts differential survival rates according to the treatment option received. A statistically significant difference (p = 0.02), in terms, of bPFS was recorded between the treatment options adopted: at 36 months bPFS was 43.3%, 18.2% and 36.1% for ADT, SBRT/S-PNLD and combined SBRT/S-PLND + ADT, respectively [Fig.1]

An MDT approach with exclusive SBRT was adopted in 9/45 pts. The median bPFS was 8.9 months. Two pts are free from progression and from ADT after 26.5 and 54 months. In 7/9 pts a new BCR was observed after a median interval of BCR after 7.8 months. Within this cluster 1/7 started ADT alone after 5.2 months, while 6/7 pts had a second round SBRT (in 2 cases combined with ADT). Overall, only 1 death was recorded, due to non-oncological cause.

Conclusion: