With the largest high-risk prostate cancer (PCa) cohort to date undergoing 68 Ga-prostate-specific membrane antigen (PSMA) PET/CT primary staging, we aimed to 1) characterize the metastatic spread of PCa in relation to tumor 68 Ga-PSMA-uptake and the D'Amico classification, and 2) compare 68 Ga-PSMA PET/CT findings with radical prostatectomy (RP) with pelvic lymph node dissection (PLND) histopathology. Methods A total of 691 consecutive newly diagnosed, biopsy-proven, treatment-naïve, D'Amico high-risk PCa patients primary staged by 68 Ga-PSMA PET/CT were included. PSMA maximum standardized uptake value (SUV max) and metastatic findings were compared to PSA level, International Society of Urologic Pathology (ISUP) grade, and clinical stage as traditional risk stratification parameters. Moreover, 68 Ga-PSMA PET/CT findings were compared with histology in RP patients undergoing PLND. Undetected lymph node metastases (LNMs) underwent immunohistochemical PSMA staining. Results Advanced disease (N1/M1) was observed in 35.3% of patients (244/691) and was associated with increasing PSA levels, ISUP grades, and clinical stages. LNMs (N1/M1a) were detected in 31.4% (217/691) and bone metastases (M1b) in 16.8% (116/691). Advanced disease frequencies in patients with ISUP grade 2 and 3 were 10.8% (11/102) and 37.1% (33/89), respectively. Risk of advanced disease for cT2a/cT2b/cT2c tumors were almost equal (24.2%, 27.9%, and 22.4%, respectively). We observed a weak correlation between SUV max and biopsy ISUP grade (ρ = 0.21; P < 0.001) and a modest correlation between SUV max and post-prostatectomy ISUP grade (ρ = 0.38; P < 0.001). Sensitivity, specificity, positive and negative predictive value, and accuracy for LNMs detection on 68 Ga-PSMA PET/CT in the PLND cohort were 30.6%, 96.5%, 68.8%, 84.5%, and 83.1%, respectively. Undetected LNMs were either micrometastases located in the lymph node border or without PSMA expression. Conclusion In this high-risk PCa cohort, we identified advanced disease in about one-third at diagnosis. ISUP grade was the superior predictor for advanced disease at diagnosis. We found a significant difference in frequency of advanced disease between ISUP grade 2 and 3, which supports the Gleason Score 7 subdivision. Interestingly, we observed no significant differences in risk of advanced disease when comparing the different cT2 stages. The undetected LNMs were either PSMA-negative or micrometastases.

There was no difference between NaF PET/CT and BS in the detection of PD and non-PD; however, BS seemingly detects PD by the PCWG-2 criteria earlier than NaF-PET, which might be explained by the fact that NaF-PET is more sensitive at the baseline scan.

Ga-PSMA PET/CT scan on a 70-year-old man with recently diagnosed prostate cancer revealed a spiculating nodule in the apex of the left lung with intense Ga-PSMA uptake. The nodule had no pathological F-FDG uptake and turned out to be a primary adenocarcinoma of the lung. Cases with complementary pattern of uptake in F-FDG and Ga-PSMA in metastatic clear cell renal carcinoma and in well-differentiated hepatocellular carcinoma have previously been reported; however, this case illustrates that this unusual pattern can also be present in primary lung cancer.

The aim of this study was to determine if additional 18 F-sodium fluoride PET/CT (NaF PET/CT) improves the prognostic accuracy in the initial staging of prostate cancer patients with normal bone scintigraphy undergoing prostatectomy. Methods: A prospective cohort study examined NaF PET/CT in intermediate-or high-risk prostate cancer with negative bone scintigraphy who were scheduled for prostatectomy. Biochemical response: PSA levels , 0.2 ng/mL at 6 wk and 6 mo postoperatively, PSA level $ 0.2 ng/mL was biochemical failure. Results: Eighty-one patients were included in the study; 75 patients (93%) achieved biochemical responses, 6 patients had biochemical failure. NaF PET/CT indicated bone metastasis in 1 patient (1.2%), was equivocal in 7 patients (8.6%), without bone metastases in 73 patients (90.1%). Eight patients with bone metastases or equivocal results on NaF PET/CT exhibited biochemical responses. All patients with biochemical failure had negative NaF PET/CT and bone scintigraphy for bone metastases. Conclusion: NaF PET/CT has no added value for bone staging in intermediate-and high-risk prostate cancer patients with normal bone scintigraphy results undergoing prostatectomy.

Ga-PSMA PET/CT is currently used for detection of prostate cancer including metastases, even at low prostate-specific antigen values. A grown number of reports have shown increased uptake of PSMA in neovessels of nonprostatic malignancies including lung cancer, and recently a case report has demonstrated increased PSMA uptake in colorectal adenocarcinoma. In this case report, we demonstrate increased Ga-PMSA uptake on PET/CT in metastases from previously treated colon adenocarcinoma, and it illustrates the importance of histology of suspicious lesions on Ga-PSMA PET/CT.

The aim of this work was to evaluate 82 Rb PET/CT as a diagnostic tool for quantitative tumor blood flow (TBF) imaging in prostate cancer (PCa). Study 1 was performed to evaluate 82 Rb as a marker of TBF, using 15 O-H 2 O PET as a reference method. Study 2 investigated the ability of 82 Rb uptake measurements to differentiate between PCa and normal prostate. Methods: Study 1: 9 PCa patients scheduled for radical prostatectomy were included. Prostate multiparametric MRI and both cardiac and pelvic 15 O-H 2 O PET and 82 Rb PET were performed. PET findings were compared with postprostatectomy Gleason grade group (GGG). Study 2: 15 primary highrisk PCa patients and 12 controls without known prostate disease were included in a clinical drug trial (EudraCT 2016-003185-26). 68 Ga-prostate-specific membrane antigen PET/CT scans of PCa patients were available. Pelvic 82 Rb PET was performed. Results: Study 1: both 82 Rb K 1 and 82 Rb SUVs correlated strongly with 15 O-H 2 O TBF (ρ 5 0.95, P , 0.001, and ρ 5 0.77, P 5 0.015, respectively). 82 Rb SUV and K 1 were linearly correlated (r 5 0.92, P 5 0.001). 82 Rb SUV correlated with postprostatectomy GGG (ρ 5 0.70, P 5 0.03). Study 2: 82 Rb SUV in PCa (3.19 ± 0.48) was significantly higher than prostate 82 Rb SUV in healthy controls (1.68 ± 0.37) (P , 0.001), with no overlap between groups. Conclusion: Study 1 shows that 82 Rb PET/CT can be used for TBF quantification and that TBF can be estimated by simple SUV and suggests that 82 Rb SUV is associated with postprostatectomy GGG and, hence, cancer aggressiveness. Study 2 shows that 82 Rb uptake is significantly higher in PCa than in normal prostate tissue with no overlap between cohorts, confirming the primary hypothesis of the clinical trial. Consequently, 82 Rb PET/CT may have potential as a noninvasive tool for evaluation of tumor aggressiveness and monitoring in nonmetastatic PCa.

We present a case of a subcutaneous process in the abdominal wall with high prostate-specific membrane antigen (PSMA) activity on Ga-PSMA PET/CT. Histology demonstrated a benign lobular capillary hemangioma with a high vascular density, with highly PSMA-positive endothelial cells. It is well known that PSMA is expressed in different tissue, including neovasculature in various malignant tumors, and the knowledge is rapidly evolving as new discoveries appear.

We present a case of a diverticulum of the sigmoid colon with intense prostate-specific membrane antigen (PSMA) activity on Ga-PSMA PET/CT. CT scan and colonoscopy showed no signs of inflammation or malignancy. This case presents an addition to the collection of benign pitfalls when reporting PSMA PET/CT; however, a Ga-PSMA up-taking focus in the colon should always cause further examination, as malignant etiology must be ruled out.