"Identification of patients who will likely benefit from PSMA-targeted radiopharmaceutical therapy remains an unmet clinical need," said first author Dr. Masatoshi Hotta, PhD, in a news release from SNMMI. The study was published March 30 in the Journal of Nuclear Medicine.

In the study, the researchers created a quantitative PSMA-PET tumor-to-salivary gland ratio (qPSG) score based on imaging in 237 men. They then interpreted the scans and assigned a visual PSG score (vPSG) based on the data. When they tested the scores in patients receiving lutetium-177 PSMA-617, patients with high qPSG and vPSG scores had longer progression-free survival and longer overall survival, according to the findings.

Representative images of six patients classified as having high, intermediate, and low vPSG scores. Image courtesy of the Journal of Nuclear Medicine.

Ultimately, the findings could be valuable in advancing precision medicine in the emerging field of theranostics, the researchers said.