Comparative analysis of treatment response to PSMA radioligand therapy using Ga-68 PSMA-11 and F-18 DCFPyL PET imaging.

Abstract

PurposeMultiple prostate-specific membrane antigen (PSMA) PET tracers are used for patient selection in radioligand therapy (RLT). This study compared treatment response to RLT across different PSMA tracers.MethodsWe retrospectively analyzed patients who underwent Lu-177 PSMA-617 RLT with baseline imaging using either Ga-68 PSMA-11 or F-18 DCFPyL PET. PET parameters were measured, including SUVmean, SUVmax, and total tumor volume (TTV). Univariable and multivariable logistic regression analyses were performed to evaluate factors associated with PSA50 response, and Cox proportional hazards regression analyses were performed to evaluate factors associated with overall survival.ResultsOf 140 patients analyzed (Ga-68 PSMA-11: n=51; F-18 DCFPyL: n=89), SUVmax and SUVmean did not differ significantly between groups; however, TTV was significantly higher in the Ga-68 PSMA-11 group (p=0.038). In multivariable analysis adjusted for age, baseline PSA, PET tracer type, SUVmean, and log-transformed TTV, PET tracer type was not significantly associated with PSA50 response (OR, 1.318; 95% CI, 0.585-2.970; p=0.505), whereas higher SUVmean was associated with greater odds of PSA50 response (OR, 1.285; 95% CI, 1.126-1.466; pConclusionPET tracer type was not significantly associated with PSA50 response or overall survival following RLT. Higher SUVmean was associated with greater odds of PSA50 response and a lower risk of death, whereas higher TTV was associated with overall survival.