68Ga-PSMA-11 PET/CT in Newly Diagnosed Prostate Adenocarcinoma

Introduction Prostate-specific membrane antigen (PSMA) ligand PET/CT is an emerging modality to detect the metastatic disease, especially in intermediate- and high-risk prostate cancer (PCa). In this study, we analyzed the contribution of 68 Ga-PSMA-11 PET/CT in staging and therapy management of newly diagnosed PCa. Materials and Methods A total of 78 patients with biopsy-proven PCa who were referred for 68 Ga-PSMA-11 PET/CT for primary staging were retrospectively analyzed. The patients were divided into risk groups according to the D'Amico risk stratification criteria. All of the patients had undergone pelvic MRI, and 65 patients had bone scintigraphy also. The findings of 68 Ga-PSMA-11 PET/CT were compared with these conventional imaging (CI) methods for staging of the disease. The relations between SUV max of the primary tumors and Gleason scores (GSs), prostate-specific antigen (PSA) levels, and metastatic extent of the disease were analyzed. Results Of 78 patients, 5 patients were in low-risk group, 18 patients were in intermediate-risk group, and 55 patients were in high-risk group. Metastatic disease was found in 40 (51.2%) of 78 patients in 68 Ga-PSMA-11 PET/CT. Ten patients had regional lymph node metastases, and 30 patients had distant metastases. 68 Ga-PSMA-11 PET/CT changed the staging in 44 (56.4%) of 78 patients compared with CI. There was significant difference between the SUV max of the tumors with GSs of 6 and 7 compared with GSs of 8, 9, and 10 ( P = 0.003). The SUV max were significantly different between the patients with no metastasis (n = 38) and patients with regional lymph node metastases or distant metastases (n = 40; 16.1 ± 10.9, 28.7 ± 25.8, P = 0.003, respectively). There was significant difference between the SUV max of patients with PSA level less than 10 ng/mL compared with patients with PSA level of 10 or greater and less than 20 ng/mL and PSA 20 ng/mL or greater ( P = 0.009). A weak correlation between PSA and primary tumor SUV max was also found ( r = 0.21). Conclusions 68 Ga-PSMA-11 PET/CT is an important imaging modality for primary evaluation of newly diagnosed PCa changing the disease stage substantially. Also the SUV max of the primary tumor has a relation with GS, metastatic extent of disease, and PSA levels defining the prognosis.