For patients undergoing prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) for recurrent prostate cancer (rPC), the probability of a true positive finding is higher with use of [68Ga]Ga-PSMA-11 than [18F]PSMA-1007, according to a study published online in the European Journal of Nuclear Medicine and Molecular Imaging.
Ian Alberts, MD, from the University of Bern in Switzerland, and colleagues retrospectively analyzed 244 patients undergoing PSMA PET/CT for rPC (122 with [68Ga]Ga-PSMA-11 and 122 with [18F]PSMA-1007). The clinical performance of the two tracers was examined, and their clinical cost efficacies were determined using data from several countries that routinely use both radiotracers.
The researchers found that compared with [68Ga]Ga-PSMA-11, the PET positivity rate was nonsignificantly higher for [18F]PSMA-1007 (91.8 versus 86.9 percent), while the rate of uncertain findings was significantly higher (17.2 versus 8.25 percent). The probability of a true positive finding was higher for [68Ga]Ga-PSMA-11 than [18F]PSMA-1007 (0.90 versus 0.81). The positive predictive value was significantly higher for [68Ga]Ga-PSMA-11 than [18F]PSMA-1007 (0.99 versus 0.86). [68Ga]Ga-PSMA-11 was favored in the intervention efficacy analysis, with a number need to image of 10.58 to achieve a true positive finding and number needed to image to harm of −8.08. In three of four jurisdictions where health economic data were available, the cost efficacy analysis favored [68Ga]Ga-PSMA-11, while in one jurisdiction, [18F]PSMA-1007 was favored.
“The higher frequency of false positives, additional imaging, or additional intervention to clarify a higher rate of indeterminate findings are indicative of a less favorable clinical performance for [18F]PSMA-1007 compared to [68Ga]Ga-PSMA-11,” the authors wrote.