PSMA Theranostics: A "Must Have" in Every Prostate Cancer Center. Illustration of Two Clinical Cases and Review of the Literature.

This manuscript describes the history of 2 patients with prostate cancer (PCa) and the role of prostate-specific membrane antigen (PSMA) theranostics in their clinical management. In the first patient, PSMA-directed positron emission tomography (PET)/computed tomography (CT) imaging was used for primary staging of high-risk PCa before initial therapy. Then after biochemical relapse it was used to plan the scope of further treatment, in which it allowed among others to perform precise target volume delineation for salvage radiotherapy for pathologic lymph nodes. In the second patient with metastatic castration-resistant prostate cancer (mCRPC), PSMA-guided imaging played a key role in the qualification for PSMA-directed radioligand therapy (RLT) with lutetium-177. We also present a review of the current literature concerning PSMA theranostics in the 2 clinical settings, ie, primary staging of PCa and PSMA RLT of mCRPC. In the first part of the review, we report on the diagnostic efficacy of various PSMA imaging radiotracers labeled with gallium-68, fluorine-18, and technetium-99m. In the second part, we describe the limitations and future perspectives of PSMA therapeutic radiopharmaceuticals, including various beta(-) and alpha emitters.