Myocardial perfusion PET imaging to evaluate coronary microvascular dysfunction in men with prostate cancer receiving androgen deprivation therapy.

211 Background: Strategies to inform cardiovascular (CV) risk are needed for prostate cancer patients initiating androgen deprivation therapy (ADT). Reduced myocardial blood flow reserve (MBFR) and coronary microvascular dysfunction (CMD) represent functional counterparts of traditional CV risk factors, including hyperlipidemia, insulin-resistance, and the metabolic syndrome. Myocardial perfusion PET stress imaging quantifies MBFR and detects CMD. However, the potential utility of these measures to indicate adverse CV changes in prostate cancer patients receiving ADT is poorly understood. Methods: In this prospective study (NCT03535987), eligible prostate cancer patients were planned for at least 6 months of ADT and curative-intent radiation therapy. All patients had a Framingham 10-year general CV risk score of at least 10% and no prior ADT exposure. Myocardial perfusion PET stress imaging was performed within 3 weeks of ADT initiation and again following 6 months of ADT exposure. MBFR was calculated as the ratio of MBF during stress / MBF during rest, and CMD was defined per established criteria as reduced MBFR (ratio < 2.0) in patients without coronary artery disease. Study outcomes included the change in MBFR following 6 months of ADT exposure and the incidence of reduced MBFR and CMD. McNemar’s test and Wilcoxon signed rank test were used for comparison of paired data. Results: Fifteen patients completed baseline myocardial perfusion PET imaging, of whom 13 completed follow-up imaging at 6 months. At baseline, the median (IQR) Framingham CV risk score was 30.4% (19.6, 35.5). One patient (7.7%) had reduced MBFR at baseline, and 5 additional patients (46.2%) developed newly reduced MBFR (ratio < 2.0) within 6 months of ADT initiation (p = 0.025). While no patients had CMD at baseline, 3 patients (30%) developed incident CMD (p = 0.083). MBFR declined in 69% of patients [median decline -0.32 (IQR -0.51, -0.22)] over 6 months ADT exposure. Conclusions: Myocardial perfusion PET imaging demonstrated a high incidence of reduced MBFR and CMD within 6 months of ADT initiation. These findings support further investigation of myocardial PET imaging, a widely-available clinical tool, as a potential research and clinical strategy to inform CV risk assessment in prostate cancer patients receiving ADT. Clinical trial information: NCT03535987.