Risk of cardiovascular events following intermittent and continuous androgen deprivation therapy in patients with nonmetastatic prostate cancer

Background: Intermittent androgen deprivation therapy (iADT) alleviates some side effects of continuous (c) ADT in patients with prostate cancer (PC), but its relative impact on ADT-associated comorbidities is uncertain. We assessed real-world use of iADT and cADT and associated risk of cardiovascular and endocrine/metabolic events in patients with nonmetastatic (nm) PC.

Methods: This retrospective longitudinal cohort study included patients with nmPC initiating systemic ADT with gonadotropin-releasing hormone agonists (goserelin, histrelin, leuprolide, and triptorelin) or antagonists (degarelix) in the US Surveillance, Epidemiology and End Results-Medicare database (2010-2017), who had ≥ 36 months of continuous insurance coverage, unless death occurred, and did not receive chemotherapy or next-generation hormonal therapies during follow-up (through 2019). Risk of major adverse cardiovascular events (MACE [myocardial infarction, stroke, cardiomyopathy/heart failure, pulmonary embolism, ischemic heart disease, all-cause mortality]) and endocrine/metabolic events (diabetes, hypercholesterolemia, bone fractures, and osteoporosis) were examined between cohorts. Inverse probability of treatment-weighted Cox regression models estimated adjusted hazard ratios (HRs) of the outcomes.

Results: Of 10,655 eligible patients, 2,095 (19.7%) received iADT and 8,560 (80.3%) cADT. Median follow-up was 43.9 and 48.4 months and median ADT duration (excluding iADT gaps) was 22.0 and 13.5 months for the iADT and cADT cohorts, respectively. Patients receiving cADT had a lower risk of MACE vs. iADT (HR 0.90; 95% confidence interval [CI] 0.83-0.96). No difference in risk of endocrine/metabolic events was observed (HR 0.97; 95% CI 0.92-1.03). Subgroup analysis found that the difference in MACE was maintained in patients with a history of cardiovascular disease (HR 0.90; 95% CI 0.83-0.98) and eliminated in patients without (HR 0.94; 95% CI 0.82-1.08).

Conclusions: Patients with nmPC who received cADT had a lower risk of MACE and similar risk of endocrine/metabolic events vs. those who received iADT. Further research assessing both regimens is needed to inform treatment decisions.