Prostate specific membrane antigen-based diagnostics

Abstract

At present, prostate cancer imaging is performed for lesion localization, detection of recurrent and/or metastatic disease, and staging. Despite significant efforts, conventional imaging of prostate cancer does not contribute to patient management as much as imaging performed for other common cancers. In addition, these imaging tests yield no information to differentiate aggressive from indolent disease that is a very important distinction in prostate disease management. In the absence of a clinically useful initial diagnostic imaging modality, biochemical tests (prostate specific antigen (PSA)), digital rectal exam, and TRUS (Transrectal Ultrasound)-guided biopsy have been widely adopted for initial diagnosis. The first post-diagnostic imaging test is often an extent-of-disease evaluation with magnetic resonance imaging (eMRI-endorectal coil). Computed tomography (CT) has a role in higher risk patients to evaluate locoregional lymphadenopathy, solid organ, or bony involvement. Bone scintigraphy with 99m Tc-MDP or, more recently, 18 F-NaF is widely used as an adjunct for detecting bone metastases. Positron emission tomography (PET) with fluorodeoxyglucose (FDG) has no role in early diagnosis and a limited role in late-stage prostate cancer because of low and heterogenous utilization of glucose by prostate carcinoma. Other nonspecific PET agents such as acetate and choline ( 11 C and 18 F-labeled) or MR-based nanoparticles, diffusion-weighted imaging, and spectroscopy may have a future role; however, the performance of these agents remains to be determined in controlled clinical trials.