Heterogeneity of [68Ga]Ga-PSMA-11 PET/CT in metastatic castration-resistant prostate cancer: genomic characteristics and association with abiraterone response

Purpose The aim of this study was to evaluate the impact of the spatial heterogeneity of prostate-specific membrane antigen (PSMA) uptake on circulating tumor DNA (ctDNA) characteristics and the response rate to new hormonal agent (NHA) treatment. Methods This retrospective study included 153 patients with metastatic castration-resistant prostate cancer (mCRPC) who underwent gallium-68 [ 68 Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) and ctDNA sequencing with a less than 2-week interval. SUVhetero was defined as the variance of SUVmean for each PSMA-positive lesion. SUVmax-mean was obtained by subtracting the SUVmax by the SUVmean. Patients receiving abiraterone treatment after [ 68 Ga]Ga-PSMA-11 PET/CT and ctDNA sequencing and with complete follow-up record were included into prostate-specific antigen (PSA) response rate analysis. PSA response was defined as a reduction of greater than 50% from baseline. Results The ctDNA detection rate was 65% (100/153). Higher SUVhetero value contributed to higher ctDNA% (Spearman’s rho = 0.278, p