Interim Scan During Radioligand Therapy for Men With Advanced Prostate Cancer
Posted: Wednesday, July 3, 2019
The addition of an interim prostate-specific membrane antigen (PSMA) positron-emission tomography (PET) scan for patients with metastatic castration-resistant prostate cancer who are being treated with lutetium-177 (Lu-177)-PSMA radioligand therapy appears to have a significant predictive value for patient survival, according to a retrospective analysis presented at the 2019 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) in Anaheim (Abstract 73) and published in The Journal of Nuclear Medicine. The researchers also discovered that the occurrence of new lesions in the PSMA PET is a prognostic factor for disease progression.
Rather than utilizing a standard uptake value, the investigators used qPSMA, a software developed in house, to determine the whole-body tumor burden. “Tumor response was assessed by the changes in PSMA-avid tumor volume from baseline to the second PSMA PET using three classification methods,” explained Andrei Gafita, MD, of the Technical University Munich, Germany, in an SNMMI press release. “Subsequently, we found that tumor response assessed on interim PSMA PET after two radioligand therapy cycles was associated with overall survival.”
The analysis included patients who underwent a gallium-68–PSMA11 PET/computerized tomography at baseline and after two cycles of Lu-177–PSMA. Tumor response was assessed by the changes in PSMA-avid tumor volume from baseline to the second PSMA PET. In all three classification methods, PSMA was significantly correlated with overall survival.
“While further analyses involving clinical parameters are warranted, this analysis paves the way for use of interim PSMA PET in a prospective setting during Lu-177–PSMA radioligand therapy,” concluded Dr. Gafita and colleagues.
Disclosure: The study authors’ disclosure information can be found at jnm.snmjournals.org.
