68Ga-PSMA-11 PET/CT in Primary and Recurrent Prostate Carcinoma: Implications for Radiotherapeutic Management in 121 Patients.

The present study analyzed the impact of Gallium-68 (68Ga)-labeled prostate-specific membrane antigen-HBED-CC (68Ga-PSMA-11) positron-emission tomography (PET)/computed tomography (CT) on radiotherapeutic management in a large cohort of men with primary or recurrent disease. Methods: This study investigated 121 men with carcinoma of the prostate who underwent 68Ga-PSMA-11 PET/CT as well as conventional imaging. 50 patients were treatment naive, 11 had persistent prostate-specific antigen (PSA) soon after surgery and 60 presented with recurrent PSA following definitive therapy. Changes in TNM classification of malignant tumors (TNM) stage and radiotherapeutic management after 68Ga-PSMA-11 imaging were compared to results achieved with conventional imaging. Results: In total, a change in TNM stage and radiotherapeutic management was observed for 49 patients (40.5%) and 62 patients (51.2%), respectively. In treatment naïve patients, a change in TNM stage and radiotheraeutic plan occurred in 26.0% and 44.0% of the cohort respectively. For patients with PSA persistence or recurrence, TNM and radiotherapeutic management changed in 50.7% and 56.3% respectively. Conclusion:68Ga-PSMA-11 PET/CT may shortly become an indispensable tool for detecting prostate cancer lesions in treatment-naïve patients as well as in men with recurrent disease or persistent PSA and seems to be very helpful in personalizing radiotherapeutic management to the individual patients' distribution of disease.

Biochemical Recurrence of Prostate Cancer: Initial Results with [18F]PSMA-1007 PET/CT.

Biochemical recurrence (BCR) is a concern for prostate cancer patients after local treatment. 68Ga-labeled prostate-specific membrane antigen (PSMA) ligands have significantly improved prostate cancer imaging. However, several 18F-labeled ligands that were developed as fluorinated tracers might present advantages. In this study, we analyzed the potential of 18F-PSMA-1007 in patients with BCR. Methods: Twelve patients with BCR after local treatment underwent PET/CT scans 1 and 3 h after injection of 18F-PSMA-1007. Results:18F-PSMA-1007 PET/CT detected lesions in 9 of 12 patients (75%). A significant difference was observed when comparing the tracer uptake in 18F-PSMA-1007-positive lesions 1 and 3 h after injection (median SUVmax, 7.00 vs. 11.34; P < 0.001; n = 76). Forty-four (88%) of 50 18F-PSMA-1007-positive lymph nodes had a short-axis diameter of less than 8 mm. Conclusion: In this pilot study, 18F-PSMA-1007 PET/CT presented high potential for localization of recurrent disease in prostate cancer patients with BCR.

Can pre-operative contrast-enhanced dynamic MR imaging for prostate cancer predict microvessel density in prostatectomy specimens?

The aim of this study was to correlate quantitative dynamic contrast-enhanced MRI (DCE MRI) parameters with microvessel density (MVD) in prostate carcinoma. Twenty-eight patients with biopsy-proven prostate carcinoma were examined by endorectal MRI including multiplanar T2- and T1-weighted spin-echo and dynamic T1-weighted turbo-FLASH MRI during and after intravenous Gd-DTPA administration. Microvessels were stained on surgical specimens using a CD31 monoclonal antibody. The MVD was quantified in hot spots by counting (MVC) and determining the area fraction by morphometry (MVAF). The DCE MRI data were analyzed using an open pharmacokinetic two-compartment model. In corresponding anatomic locations the time shift (Deltat) between the beginning of signal enhancement of cancer and adjacent normal prostatic tissue, the degree of contrast enhancement and the contrast exchange rate constant (k21) were calculated. The MVC and MVAF were elevated in carcinoma (p<0.001 and p=0.002, respectively) and correlated to k21 (r=0.62, p<0.001 and r=0.80, p<0.001, respectively). k21-values of carcinoma were significantly higher compared with normal peripheral but not central zone tissue. Deltat was longer in high compared with low-grade tumors (p=0.025). The DCE MRI can provide important information about individual MVD in prostate cancer, which may be helpful for guiding biopsy and assessing individual prognosis.