The Risk of Cardiovascular Disease in Prostate Cancer Patients Receiving Androgen Deprivation Therapies

Background Androgen deprivation therapy (ADT), which has a proven role in prostate cancer management, has been associated with various cardiovascular diseases. However few studies have investigated these associations by type of ADT, particularly for newer ADTs such as the gonadotropin-releasing hormone (GnRH) antagonist degarelix. We investigated the risk of cardiovascular disease by type of ADT in a real world setting.MethodsMen newly diagnosed with prostate cancer, from 2009 to 2015, were identified from the Scottish Cancer Registry. ADTs were identified from the nationwide Prescribing Information System. Cardiovascular events were based upon hospitalisation (from hospital records) or death from cardiovascular disease (from death records). Cox regression calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for cardiovascular events with time-varying ADT exposure, comparing ADT users with untreated patients, after adjusting for potential confounders including prior cardiovascular disease.Results The cohort contained 20,216 prostate cancer patients, followed for 73,570 person years, during which there were 3,853 cardiovascular events. ADT was associated with a 25% increase in cardiovascular events (adjusted HR=1.25 95% CI 1.16, 1.35). This reflected increases in cardiovascular events associated with GnRH agonists (adjusted HR=1.26 95% CI 1.16, 1.36), degarelix (adjusted HR=1.49 95% CI 1.16, 1.90), but not bicalutamide monotherapy (adjusted HR=1.01 95% CI 0.82, 1.25). Conclusions There were increased risks of cardiovascular disease with use of GnRH agonists and degarelix, but not with bicalutamide monotherapy. This is the first study to observe increased cardiovascular risks with degarelix, but the cause of this association is unclear and merits further investigation.