Oligometastatic Disease Detection with (68)Ga-PSMA-11 PET/CT in Hormone-Sensitive Prostate Cancer Patients (HSPC) with Biochemical Recurrence after Radical Prostatectomy: Predictive Factors and Clinical Impact

SIMPLE SUMMARY: The early treatment of oligometastatic disease (OMD) is a promising therapeutic option for prostate cancer as it has the potential of delaying androgen-deprivation therapy (ADT) and disease progression. Next-generation imaging targeting the prostate-specific membrane antigen (PSMA-PET/CT) is considered the most accurate technique for recurrent prostate cancer. Finding clinico-pathological factors predicting positivity with OMD detection on PSMA-PET/CT, as well as assessing its impact on treatment management, were the main objectives of our study. We selected a homogenous population of ADT-free prostate cancer patients with a PSMA-PET/CT performed at biochemical recurrence (BCR) after radical prostatectomy (RP). OMD was detected in 44% of patients for a total positivity rate of 60%. PSA at the moment of PET, PSAdt, and the absence of previous salvage treatment were factors predicting PSMA-PET/CT positivity with OMD. A change in clinical management occurred in more than half of the patients, mostly to perform metastasis-directed therapy after OMD detection. ABSTRACT: Metastasis-directed therapy (MDT) in oligometastatic prostate cancer has the potential of delaying the start of androgen deprivation therapy (ADT) and disease progression. We aimed to analyze the efficacy of PSMA-PET/CT in detecting oligometastatic disease (OMD), to look for predictive factors of OMD, and to evaluate the impact of PSMA-PET/CT findings on clinical management. We retrospectively analyzed a homogeneous population of 196 hormone-sensitive prostate cancer patients (HSPC), considered potential candidates for MDT, with a PSMA-PET/CT performed at biochemical recurrence (BCR) after radical prostatectomy (RP). Multivariable logistic regression analysis was performed based on several clinico-pathological factors. Changes in clinical management before and after PSMA-PET/CT were analyzed. The OMD detection rate was 44% for a total positivity rate of 60%. PSMA-PET/CT positivity was independently related to PSA (OR (95% CI), p) (1.7 (1.3–2.3), p < 0.0001) and PSAdt (0.4 (0.2–0.8), p = 0.013), and OMD detection was independently related to PSA (1.6 (1.2–2.2), p = 0.001) and no previous salvage therapy (0.3 (0.1–0.9), p = 0.038). A treatment change was observed in 58% of patients, mostly to perform MDT after OMD detection (60% of changes). This study showed that PSMA-PET/CT is an excellent imaging technique to detect OMD early in HSPC patients with BCR after RP, changing therapeutic management mostly into MDT.