Serial [18F]-FDHT-PET to predict bicalutamide efficacy in patients with androgen receptor positive metastatic breast cancer

BackgroundThe androgen receptor (AR) is a potential target in metastatic breast cancer (MBC), and 16?-[18F]-fluoro-5?-dihydrotestosterone positron emission tomography ([18F]-FDHT-PET) can be used for noninvasive visualisation of AR. [18F]-FDHT uptake reduction during AR-targeting therapy reflects AR occupancy might predictive treatment response. We assessed the feasibility [18F]-FDHT-PET to detect changes availability bicalutamide correlated these with response.Patients methodsPatients + MBC, regardless oestrogen status, received an at baseline after 4–6 weeks treatment. Baseline was expressed as maximum standardised value. Percentage change tracer uptake, corrected background activity (SUVcor), between follow-up PET scan (% reduction), per-patient lesion. Clinical benefit determined accordance Response Evaluation Criteria Solid Tumours (RECIST) 1.1 or clinical evaluation (absence disease progression ?24 weeks).ResultsBaseline 21 patients detected 341 515 lesions found standard imaging new lesions. Follow-up evaluable 17 349 lesions, showing decrease median SUVcor from 1.3 0.7 lesion (P < 0.001). Median % ?45% per-lesion ?39%. In progressive (n = 11), ?30% versus ?53% who showed (in RECIST 3) 3); P 0.338).ConclusionIn this study, bicalutamide-induced could by MBC. However, not predict response.Clinical trial informationNCT02697032.