A recent study compared the relative risk of cardiovascular ischemic events in patients with prostate cancer after surgical castration vs gonadotropin-releasing hormone agonist (GnRHa) therapy, published in the Journal of Clinical Oncology (online October 2, 2017; doi:10.1200/JCO.2016.71.4204).
Prior research has shown that androgen deprivation therapy (ADT) in patients with prostate cancer may increase the risk of cardiovascular ischemic events such as myocardial infarction and ischemic stroke. However, the data are limited for determining whether bilateral orchiectomy or GnRHa therapy results in worse long-term outcomes.
A group of Taiwanese researchers conducted a study to determine whether cardiovascular risk in patients with prostate cancer differs between those receiving ADT by surgical castration and those receiving GnRHa therapy. A total of 14,715 patients were identified from the Taiwan National Health Insurance Research Database from 1997 to 2011. Overall, 3578 patients (24.3%) underwent bilateral orchiectomy and 11,137 patients (75.7%) received GnRHa therapy.
Cox regression models were utilized to identify risk factors for myocardial infarction, ischemic stroke, and cardiac-related complications.
Researchers reported that patients from both groups had a similar risk of cardiovascular ischemic events (HR, 1.16; 95% CI, 0.97-1.38) during a median follow-up period of 3.3 years. However, data from the initial 1.5 years of follow-up showed that there was a higher percentage of cardiovascular ischemic events in the bilateral orchiectomy group than in the GnRHa group (HR, 1.40; 95% CI, 1.04-1.88). This discrepancy was particularly prominent in patients who were at least 65 years of age, demonstrated hypertension, had a Charlson comorbidity index score of at least 3, and had a previously documented history of myocardial infarction, ischemic stroke, or coronary heart disease.
In their concluding remarks, researchers wrote that bilateral orchiectomy and GnRHa offer comparable long-term risk of cardiovascular ischemic events in patients with prostate cancer. “These findings can help clinicians decide on the optimal castration strategy for individual patients,” they asserted.—Zachary Bessette