AUTHOR=Fernandes Bruna , Roy Jyoti , Basuli Falguni , Warner Blake M. , Lindenberg Liza , Mena Esther , Adler Steven S. , Griffiths Gary L. , Choyke Peter L. , Lin Frank I. 

TITLE=Salivary excretion of systemically injected [18F]DCFPyL in prostate cancer patients undergoing PSMA scans

JOURNAL=Frontiers in Oncology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2024.1367962

DOI=10.3389/fonc.2024.1367962

ISSN=2234-943X

ABSTRACT=<sec><title>Introduction</title><p>Prostate-specific membrane antigen (PSMA) is present in high amounts in salivary glands, but it is unclear whether labeled binders of PSMA are excreted in the saliva.</p></sec><sec><title>Methods</title><p>Ten patients with prostate cancer underwent whole-body [<sup>18</sup>F]DCFPyL PET/CT (NCT03181867), and saliva samples were collected between 0-120 minutes post-injection. [<sup>18</sup>F]DCFPyL salivary excretion was measured over 120 minutes and expressed as %ID/g. Protein-associated binding was estimated by the percentage of [<sup>18</sup>F]DCFPyL versus parent radiotracer.</p></sec><sec><title>Results</title><p>All PET scans of 10 patients (69 ± 8 years) with histologically confirmed prostate cancer (PSA= 2.4 ± 2.4, and Gleason Grade = 6-9) showed high uptake of [<sup>18</sup>F]-DCFPyL in salivary glands while 8 patients demonstrated high uptake in the saliva at 45 minutes. The intact [<sup>18</sup>F]-DCFPyL (98%) was also confirmed in the saliva samples at 120 min with increasing salivary radioactivity between 30-120 min.</p></sec><sec><title>Conclusion</title><p>Systemically injected [<sup>18</sup>F]DCFPyL shows salivary gland uptake, an increasing amount of which is secreted in saliva over time and is not maximized by 120 minutes post-injection. Although probably insignificant for diagnostic studies, patients undergoing PSMA-targeted therapies should be aware of radioactivity in saliva.</p></sec>