The Role of Radiolabeled PSMA PET/CT for the Evaluation of Renal Cancer - Beyond the Abstract

Prostate specific membrane antigen (PSMA) is highly expressed in the cell surface of the tumor microvasculature of several solid tumors, including renal cell carcinoma (RCC). Radiolabeled PSMA-based positron emission tomography (PET)/computed tomography (CT) has extensively used for the detection of recurrent prostate cancer, but it would be useful also in other solid cancer, like RCC. In the present mini-review, we aim to understand the current role of PSMA PET/CT in patients affected by RCC.

A systematic literature search for studies on PET/CT in patients with RCC until to April 2018 was carried out. MEDLINE databases, such as Pubmed, Web of Science and Scopus were consulted. Thirteen articles were retrieved from the available literature.

UroToday BTA PRISMA flow chart
Figure 1. The PRISMA flow-chart

The majority of them were relative to the metastatic RCC (n=11/13, 85%), and in many cases, they were configured as a clinical case (n=9/13; 69%). A total of 37 patients with RCC underwent PSMA for the staging/restaging of disease, while only 3 patients affected by urothelial cancer were sent to PSMA PET/CT. In the studies above the initial staging of RCC, PSMA-based PET/CT was found to be a useful imaging modality in the assessment of lesions that remained unclear on conventional imaging. In the metastatic setting, PSMA PET/CT was able to detect more RCC lesions than Fluorodeoxyglucose (FDG) PET/CT, particularly in patients with a well-differentiated tumor. Moreover, the opportunity to detect the presence of metastasis by 68Ga-PSMA PET/CT open the opportunity to treat with 177Lu-PSMA. Finally, PSMA offers the possibility of being used as a functional imaging agent to measure and/or predict response to agents that target the tumor neovasculature (e.g. tyrosine kinase inhibitors and bevacizumab) by providing an in vivo readout of neovascular density in these lesions. In conclusion, PSMA PET seems a useful imaging modality for the evaluation of disease widespread and for the evaluation of response to target and local therapy in patients with RCC.

Written By: Laura Evangelista, M.D., Ph.D., Nuclear Medicine and Molecular Imaging Unit, Veneto Institute of Oncology, Padova, Italy