Role of FDG PET/CT in Management of Patients with Prostate Cancer

Prostate cancer is the second most common cancer in men worldwide. [¹⁸F]FDG PET/CT imaging, a well-known and effective technique for detecting malignancies, has not been considered a useful tool for prostate cancer imaging by many because of its perceived low [¹⁸F]FDG uptake. Incidentally detected focal [¹⁸F]FDG uptake in the prostate is not uncommon, and typically benign. Imaging features that would increase concern for an underlying prostatic carcinoma, include focal uptake in the periphery near the gland margin without calcifications. [¹⁸F]FDG PET/CT imaging provides little value in the initial staging of prostate cancer, particularly in the era of prostate specific membrane antigen (PSMA) radiotracer. In cases of biochemical recurrence, the value of [¹⁸F]FDG PET/CT increases notably when Grade group 4 or 5 and elevated PSA levels are present. Active research is underway for theranostic approaches to prostate cancer, including [¹⁷⁷Lu]Lu-PSMA therapy. Dual tracer staging using FDG and PSMA imaging significantly enhances the accuracy of disease site assessment. Specifically, the addition of [¹⁸F]FDG PET/CT imaging allows for the evaluation of discordant disease (PSMA negative/FDG positive). The maximal benefit from [¹⁷⁷Lu]Lu-PSMA therapy relies on significant PSMA accumulation across all disease sites, and the identification of discordant disease suggests that these patients may derive less benefit from the treatment. The genuine value of [¹⁸F]FDG PET/CT imaging lies in advanced prostate cancer, PSMA-negative disease, as a prognostic biomarker, and the realm of new targeted theranostic agents.