“Additional research is needed to better understand the potential risks and benefits of ADT, so that this treatment can be targeted to patients for whom the benefits are clearest,” conclude the Boston-based authors of the report in European Urology published online February 1.
Dr. Jim C. Hu, with Brigham and Women’s Hospital, and colleagues point out that ADT is known to increase the risk of coronary artery disease and stroke, but there’s little information abut its effect on peripheral vascular risk. To investigate, they examined data from the population-based SEER tumor registry linked to Medicare data and identified 182,757 men ages 65 and older with nonmetastatic prostate cancer.
“We focused on men with nonmetastatic disease, because the indication for ADT remains unclear for many men treated in this setting, and thus the risk of harm is potentially greater,” the researchers explain.
Half the men received ADT, either with GnRH agonists (47.8%) or orchiectomy (2.2%).
During a median follow-up of 5.1 years, incidence rates per 1000 person years for PAD were 30.5 in the GnRH group, 27.1 in the orchiectomy group, and 21.0 among those not treated with androgen deprivation. Corresponding rates of incident VTE were 13.2, 14.7 and 10.1 per 1000 person-years.
After adjustment, GnRH agonist use was associated with significantly increased risk of PAD (hazard ratio 1.16) and VTE (HR 1.10). Similarly, the hazard ratios associated with orchiectomy were 1.13 and 1.27, respectively.
The team also found that increasing levels of comorbidity were strongly associated with these outcomes. In discussing the findings, they comment: “It is also notable that the increased risks (with ADT) were relatively modest and smaller than for the risk of increasing levels of comorbidity. This finding underscores the importance of addressing known risk factors for PAD and venous thromboembolism, especially for patients who are likely to benefit from ADT.”