Serial FDG-PET imaging of metastatic prostate cancers reveals intrapatient intermetastases polyclonality through same patient heterogeneous responses to systemic therapy.

e590Background: Although intrapatient prostate cancer (PCa) metastasis polyclonality has been recently characterized by genomic and transcriptomic studies, systemic treatment response heterogeneity has yet to be reported or imaged. It remains unknown if polyclonal differentiation leads to heterogeneous treatment responses between metastases in a single patient undergoing therapy. Methods: Between 2010 and 2015, fifteen patients with metastatic PCa were imaged by FDG-PET/CT before and during systemic therapy, and metabolic response was recorded for individual metastatic lesions. Intermetastasis heterogeneity was defined by opposite metabolic responses of at least two metastases from the same compartment (bone or soft tissue) between the two scans. We examined intrapatient intermetastasis heterogeneity of response to systemic therapy based on the assessment of metabolic response in a total of 165 individual lesions (change in SUVmax, complete response, or new lesion). Change in total lesion glycolysis (TLG)...