Positron Emission Tomography Radiotracers for Identification of Site of Recurrence in Prostate Cancer After Primary Treatment Failure.

Despite substantial improvement in the definitive management of primary prostate cancer, a significant number of patients experience biochemical recurrence-a clinical state in which serum prostate-specific antigen (PSA) levels rise prior to the development of physical signs or symptoms. The early detection and localization of biochemical recurrence may confer eligibility for salvage therapy; therefore, imaging techniques that provide accurate disease visualization are imperative. In this review, we discuss various imaging methods for localizing disease in the context of biochemical recurrence in prostate cancer. Particularly, we describe available or investigational positron emission tomography (PET) radiotracers, such as F-FDG, F-NaF, choline (both F and C), the F-labeled amino acid derivative fluciclovine, prostate-specific membrane antigen (PSMA) radioligands, and the short peptide compound bombesin. Generally, PET radiotracers such as F-FDG, F-NaF, and F/C choline have fallen out of favor because of their inferior sensitivity and/or specificity in relation to more recently developed radiotracers. F-fluciclovine has addressed these shortcomings by exploiting the upregulation of amino acid transporters in tumors; however, PSMA-targeting agents have significantly advanced the management of biochemical recurrence of prostate cancer through their high sensitivity and specificity, enabling the identification of candidates for radionuclide therapy. Investigational agents, such as bombesin-based radiotracers, may address the shortcomings of treating prostate cancer with little to no PSMA expression.