Risk of Cardiovascular Ischemic Events After Surgical Castration and Gonadotropin-Releasing Hormone Agonist Therapy for Prostate Cancer: A Nationwide Cohort Study

Abstract

Purpose Our aim was to determine whether cardiovascular (CV) risk in patients with prostate cancer (PCa) differs between those who receive androgen-deprivation therapy by surgical castration and those who receive gonadotropin-releasing hormone agonist (GnRHa) therapy. Patients and Methods By using the Taiwan National Health Insurance Research Database, we analyzed data from 14,715 patients with PCa diagnosed from January 1, 1997, through December 31, 2011. The patients were treated with bilateral orchiectomy or GnRHa therapy. We used inverse probability of treatment weighting with propensity scores to adjust for the imbalance in covariate baseline values between these two groups. Cox regression models were used to identify risk factors for myocardial infarction (MI), ischemic stroke (IS), and cardiac-related complications. Results Overall, 3,578 patients with PCa (24.3%) underwent bilateral orchiectomy and 11,137 patients (75.7%) received GnRHa therapy. Both groups had a similar risk of CV ischemic events (ie, MI or IS; hazard ratio, 1.16; 95% CI, 0.97 to 1.38) during a median follow-up time of 3.3 years. However, during the first 1.5 years of follow-up, there were higher CV ischemic events in the orchiectomy group than in the GnRHa group (hazard ratio, 1.40; 95% CI, 1.04 to 1.88), particularly in patients who were ≥ 65 years of age, had hypertension, had a Charlson comorbidity index score ≥ 3, and had a previous history of MI, IS, or coronary heart disease. Conclusion Compared with bilateral orchiectomy, use of GnRHa does not increase the risk of CV ischemic events in patients with PCa. Nonetheless, orchiectomy is associated with higher rates of CV ischemic events in older patients and those with a history of CV comorbidities within 1.5 years of initiating androgen-deprivation therapy. These findings can help clinicians decide on the optimal castration strategy for individual patients.