Long-term Impact of Androgen-deprivation Therapy on Cardiovascular Morbidity After Radiotherapy for Clinically Localized Prostate Cancer

ObjectiveTo characterize the impact of androgen-deprivation therapy (ADT) on the incidence of cardiovascular events (CE) in prostate cancer patients treated with radiotherapy (RT).Materials and MethodsThere were 2211 patients with localized prostate cancer treated with RT from 1988 to 2008 at our institution. There were 991 patients (44.8%) who received ADT at the time of RT for a median of 6.1 months. Salvage ADT was initiated prior to CE in 365 men (16.5%) at a median of 5.5 years (range: 0.6 to 18.4 years) after RT and continued for a median of 4.3 years. A nomogram was constructed to predict the 10-year risk of CE “post-RT” (i.e., after RT).ResultsPatients receiving ADT at the time of RT exhibited significantly higher 10-year incidence of CE (19.6%, 95% CI 17.0%-22.6%) than those not receiving ADT (14.3%, 95% CI 12.2%-16.7%, P  =  .005). On multivariate analysis, both ADT at the time of RT (P  =  .007) and the time of salvage (P = .0004) were associated with increased CE risk, as were advanced age (P  =  .02), smoking (P  =  .0007), history of diabetes (P  =  .0007), and history of CE before RT (P  <  .0001). A nomogram using patient age, smoking status, history of pre-RT CE, history of diabetes, and ADT use at the time of RT predicted the rate of 10-year CE with a C-index of 0.81 (95% CI, 0.72-0.88).ConclusionWhile ADT is often an essential part of prostate cancer treatment, patients should be counseled regarding increased risks of CE and prophylactic efforts should be considered to mitigate that risk.