Impact of Dual-Tracer ⁶⁸Ga-PSMA/¹⁸F-FDG PET/CT on the Characterization of Tumor Heterogeneity and Clinical...

Prostate cancer is one of the most common malignancies among men worldwide, and its incidence is also significant in Ecuador. This disease can present marked biological heterogeneity, particularly in advanced stages, such as metastatic and castration-resistant prostate cancer, which may influence both imaging findings and therapeutic decisions. We report an index case in Ecuador in which combined gallium-68 prostate-specific membrane antigen (⁶⁸Ga-PSMA) and fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) was used for the comprehensive characterization and longitudinal follow-up of a patient with high-volume metastatic prostate cancer, highlighting the complementary metabolic and molecular information provided by both imaging tracers. The dual-tracer approach revealed discordant lesions - with differential PSMA and FDG uptake - highlighting substantial metabolic heterogeneity and guiding an intensified therapeutic strategy consisting of combined chemotherapy (docetaxel + carboplatin), androgen deprivation therapy, and androgen receptor inhibition. Follow-up dual PET imaging demonstrated a 99% reduction in tumor burden and complete metabolic remission, underscoring the value of this approach in treatment planning, assessment of disease extent, and response evaluation. This case illustrates the importance of dual-tracer PET/CT with PSMA and FDG as an essential tool for accurate disease characterization, personalized treatment selection, and identification of aggressive tumor subpopulations in advanced prostate cancer.