Outcome After 68Ga-PSMA-11 versus Choline PET-Based Salvage Radiotherapy in Patients with Biochemical Recurrence of Prostate Cancer: A Matched-Pair Analysis

Abstract

The purpose of this analysis was primarily to analyze biochemical-recurrence free survival (BRFS) after positron emission tomography (PET)-guided salvage radiotherapy (sRT) in a large cohort, and to further compare BRFS after PSMA vs. choline PET/ computer tomography (CT)-based sRT. This retrospective analysis is based on 421 patients referred for PSMA or choline PET/CT after radical prostatectomy due to biochemically recurrent or persistent disease. BRFS (PSA: 0.2 ng/mL) was defined as the study endpoint. Cox regression analyses were performed to assess the impact of different clinical parameters on BRFS. Additionally, propensity score matching was performed to adjust patient cohorts (PSMA vs. choline PET/CT-based sRT). The median follow-up time was 30 months. BRFS at three years after sRT was 58%. In the multivariate analysis, only PSA before PET imaging and PSA before sRT were significantly associated with BRFS (p < 0.05). After propensity score matching, 272 patients were further analyzed; there was no significant difference in three-year BRFS between patients with PSMA PET-based vs. choline PET-based sRT (55% vs. 63%, p = 0.197). The present analysis confirmed the overall high BRFS rates after PET-based sRT and the strong prognostic effect of PSA level prior to sRT. PSMA PET-based sRT did not have superior BRFS rates when compared with choline PET-based sRT.

Comparison of Hormone-Sensitive Oligorecurrent Prostate Cancer Patients Based on Routine Use of Choline and/or PSMA PET/CT to Guide Metastasis-Directed Therapy

“…On the other hand, this study, thanks to a median follow-up higher than that found in the literature [ 31 , 32 , 33 ], i.e., 42.2 months, demonstrated the prolonged efficacy of treatment using RT guided by PET/CT on both BR-FS and ADT-FS in the PET-PSMA group. The differences in duration of BR-FS and ADT-FS between the two groups could be explained by the more exhaustive PSMA PET/CT assessment when the PSA is ≤2 ng/mL due to the known performances of the two radiopharmaceuticals [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”

“…To our knowledge, 3 major points in our study need to be underlined and allow it to stand out in the literature, namely, the 3 studies comparing the efficacy of treatment focused on oligo-recurrences using RT guided by FCH or PSMA in clinical routine for PC recurrence [ 31 , 32 , 33 ]. The main results of these studies are detailed in Table S1 .…”

“…For this reason, it seemed interesting to us to compare the efficacy of RT treatment guided by PSMA-PET or FCH-PET in BR patients with low PSA values. The literature reports 3 retrospective studies comparing RT treatment guided by PSMA-PET or FCH-PET on small cohorts of BR patients with heterogeneous PSA values between the groups [ 31 , 32 , 33 ]. Two of these suggest that PSMA-PET-guided SBRT obtained better results than FCH-PET [ 31 , 32 ].…”

“…Two of these suggest that PSMA-PET-guided SBRT obtained better results than FCH-PET [ 31 , 32 ]. On the other hand, the other study did not find any difference in biological recurrence-free survival (BR-FS) between the two groups [ 33 ]. The debate remains open.…”

Adaptive sequential plan-on-plan optimization during prostate-specific antigen response guided radiotherapy of recurrent prostate cancer

“…New imaging methods with improved sensitivity and specificity will affect radiotherapy planning for future patients with recurrent prostate cancer. The diagnosis of lymph node metastases enables treatment planning upfront of both local recurrence and lymph node metastases [28] , [29] . However, still a large proportion of these patients will have either no lymph node metastases or possibly findings of uncertain value.…”