The Role of Ga-68 PSMA PET/CT Scan on Differentiating of Oligometastatic and High Risk Prostate Cancer

Objectives: In this study, we aimed to investigate whether Ga-68 prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) scanning is adequate to predict intermediate risk, high risk, or oligometastatic prostate cancer (PCa) as an initial staging modality. Methods: The Ga-68 PSMA PET/CT scan images of 50 PCa patients pathologically proven by transrectal ultrasound guided biopsy were evaluated retrospectively. The association of standard uptake value maximum (SUVmax) value of the area with the highest PSMA expression within the primary tumor with the risk groups and metastatic burden is investigated. Results: The SUVmax value was 6.18 in oligometastatic patients where it was measured as 10.93 in patients with higher metastatic burden (p=0.037). The cut-off SUVmax value for multiple metastases was 7.96 (p=0.047). According to the regression model, SUV max value has a positive influence [odds ratio (OR)=1.42], which was statistically significant (p=0.038). SUVmax values for intermediate and high risk patients were 6.91 and 11.44, respectively (p=0.014). The cut-off SUVmax value for the high risk group was 10.55 (p=0.006). In the regression model, SUV max value has a positive influence (OR=1.198), which was statistically significant (p=0.021). Conclusion: In this paper, we demonstrated the association between SUVmax value of primary tumor and Gleason score. Our results also allowed us to suggest that primary tumor SUVmax is a sufficiently accurate predictor of D'Amico risk groups in newly diagnosed PCa cases. Additionally, Ga-68 PSMA PET/CT turns out to be a useful tool in determiningoligometastatic PCa, which requires a different treatment approach.