Dynamic 68Ga-PSMA-11 PET/CT for the Primary Evaluation of Localized Renal Mass: A Prospective Study

Purpose: The potential role of prostatic-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in non-prostate cancer tumors has shown promising results. We examined the performance of dynamic 68Ga-PSMA-11 PET/CT (DPSMA) for the evaluation of localized renal mass. Methods: A prospective case series of patients with a newly diagnosed renal mass who were referred for surgery. DPSMA was performed in a standardized manner before surgery. The final surgical histology served as the standard of reference. PSMA expression in the tumor vasculature was assessed and staining intensity was scored. Tracer uptake and PSMA expression were compared between benign and malignant tissue. Results: Of 29 enhancing renal masses evaluated in 27 patients, 24 (83%) were malignant lesions. The median mean standardized uptake value (SUVmean) of benign and malignant lesions was 2.3 (IQR 2.2-2.7) and 6.8 (IQR 4.2-10.2), respectively (P = 0.009). Median SUVmax of benign and malignant lesions was 3.8 (IQR 3.3-4.5) and 9.4 (IQR 5.4-15.8), respectively (P = 0.01), respectively. The median washout coefficient (K2) was significantly lower in malignant lesions compared to benign lesions (0.16 versus 0.80, P = 0.006). Positive PSMA staining was found in 20/24 malignant lesions and 2/5 benign lesions (P = 0.04). Conclusion: This pilot study demonstrated DPSMA uptake and kinetics in localized renal masses. Increased 68Ga-PSMA-11 tracer uptake and intra-tumoral retention correlate with PSMA expression in malignant renal tumors compared with benign renal masses, supporting further assessment of DPSMA as a potential tool for evaluating localized renal masses.