[F]Fluorthanatrace PET in Ovarian Cancer: Comparison with [F]FDG PET, Lesion Location, Tumor Grade, and Breast Cancer Gene Mutation Status.

Poly(adenosine diphosphate-ribose) polymerase-1 (PARP1) inhibitors have improved ovarian cancer treatment outcomes. However, clinical response remains heterogeneous. Existing biomarkers, mainly breast cancer susceptibility genes 1 and 2 (), are suboptimal. New tools are needed to guide patient selection. In this study, [F]fluorthanatrace ([F]FTT), a PET radiotracer for imaging PARP1, was compared with [F]FDG and tumor features commonly assessed in ovarian cancer. Subjects with epithelial ovarian cancer underwent both [F]FTT and [F]FDG PET before new oncologic treatment. The SUV of [F]FTT and [F]FDG was compared between lesions. [F]FTT SUV was compared with tumor location, tumor grade, and germline or somatic status. Linear mixed models were fitted to identify subject-level differences. Fifty-five lesions were identified in 14 subjects. No correlation was found between [F]FTT SUV and [F]FDG SUV per lesion, supporting distinct molecular targets. [F]FTT uptake varied widely across lesions, with no significant differences between mean SUV and tumor location, grade, or status. Our findings suggest that [F]FTT PET may provide unique information on ovarian cancer distinct from [F]FDG PET and commonly assessed tumor features. Our results imply a wide range of PARP1 expression in the studied ovarian tumors not explained by [F]FDG PET, location, grade, or mutational status.