SAN FRANCISCO – New findings on cardiovascular and metabolic risks in men receiving androgen deprivation therapy for nonmetastatic prostate cancer may help individualize decisions about whether to initiate this therapy and how long to continue it.
In a population-based cohort study of more than 3,500 men followed up for 15 years, taking androgen deprivation therapy (ADT) for 2 years or less did not significantly increase the risk of either cardiovascular disease or diabetes, researchers reported at the 2014 Genitourinary Cancers Symposium sponsored by the American Society of Clinical Oncology.
Dr. Alicia K. Morgans
Taking it for more than 2 years did increase these risks, but only for men about 75 years of age or older at baseline, first author Dr. Alicia K. Morgans of Vanderbilt University, Nashville, Tennessee, reported in a poster presentation.
As would be expected, comorbidities were also a risk factor for both cardiovascular disease and diabetes.
"There may be a different risk-benefit ratio of ADT in younger men as compared to older men," Dr. Morgans commented in an interview.
"The take-home message is that younger men don’t need to worry so much about the development of diabetes and cardiovascular disease directly related to ADT. Certainly, their other comorbidities may predispose them to developing that complication, but not related to ADT," she elaborated.
"For older men, especially men who have more complicated medical histories with more comorbidities, it is something that they need to consider, and potentially, if they have the ability to choose not to have ADT, if they have a more complicated medical picture and are older, they may want to opt against it," she added.
While acknowledging the potentially heightened risks of these conditions with ADT, guidelines are vague as to monitoring for them, according to Dr. Morgans. "We simply say at this point: watch. Watch for the development of diabetes, watch for the development of cardiovascular disease. And there are no age criteria for that either," she said, so these new data may help in that arena, too.
The investigators analyzed data from the Prostate Cancer Outcomes Study for men aged 39-89 years from six U.S. geographic regions with nonmetastatic prostate cancer diagnosed during 1994-1995 and followed up through 2009-2010.
The presence of cardiovascular disease and diabetes was ascertained from patient surveys at baseline; at 6 months; and at 1, 2, 5, and 15 years, and from death certificates.
Analyses were based on 3,526 men who survived at least 2 years after diagnosis. They had a median age of about 68 years at baseline, and roughly half had at least one comorbidity.
Overall, 23% took ADT for 2 years or less, 9% took ADT for more than 2 years, and the rest did not take any. The median duration of follow-up was about 10 years.
Main results showed that taking ADT for 2 years or less did not significantly increase the risk of developing cardiovascular disease or diabetes, regardless of age at the start of therapy, Dr. Morgans reported.
In contrast, among patients who took ADT for more than 2 years, the risks increased with age at baseline and became significant in the mid-70s. Specifically, men older than 74 years had a significantly elevated risk of cardiovascular disease and men older than 76 years had a significantly elevated risk of diabetes.
Risks also rose with the number of comorbidities, but tumor grade, extent of prostate cancer, and race did not significantly affect these outcomes.
Dr. Morgans disclosed no relevant conflicts of interest.