More studies are needed to be sure of that. Meanwhile, men with prostatecancercancer and their doctors should weigh the risks and benefits of such treatment, say the researchers.
They included Nancy Keating, MD, MPH, of Harvard Medical School's health care policy department. Their study appears in the Journal of Clinical Oncology.
"This study shows that a common hormonal treatment for prostate cancer may put men at significant risk for other serious diseases," Keating says, in a Harvard news release.
"Patients and physicians need to be aware of the elevated risk as they make treatment decisions," Keating adds.
About the Study
Keating and colleagues checked medical records of more than 73,000 men enrolled in MedicareMedicare who were diagnosed with prostate cancer between 1992 and 1999.
The men were all at least 66 years old (average age: 74). They had local or regional prostate cancer, meaning their cancer hadn't spread far beyond the prostate.
Keating's team didn't assign the men to any particular treatment. Instead, the researchers simply noted the men's hormonal treatment.
A third of the men took hormonal drugs called gonadotropin-releasing hormone agonists (GnRH agonists such as Lupron and Zoladex) and 7% of the men had surgery to remove both of their testicles (bilateral orchiectomy).
The researchers followed the men for about 4.5 years, on average. During that time:
- 3,917 men had a heart attackheart attack (about 5%)
- 3,301 men had sudden cardiac death (4.5%)
During the follow-up period, diabetesdiabetes was diagnosed in 11% of the men who didn't have diabetes when the study started.
Coronary heart diseaseheart disease was diagnosed in a quarter of the men who didn't have coronary heart disease when the study started.
Risk Higher With Hormone Therapy
During the study, men taking a GnRH agonist were 16% more likely to die from sudden cardiac death, 11% more likely to have a heart attack, 16% more likely to be diagnosed with coronary heart disease, and 44% more likely to be diagnosed with diabetes, compared to those with no treatment.
The higher risk of being diagnosed with diabetes and coronary heart disease "was evident among men on GnRH agonist therapy for as few as one to four months," the researchers write.
Higher risk of heart attack and sudden cardiac death were also seen in men who only used GnRH agonists for a short time, but those findings may have been due to chance.
Men who had orchiectomy were 34% more likely to develop diabetes than those who didn't get treatment.
The odds of having a heart attack, sudden death, or new coronary heart disease weren't associated with testicle removal.
The study doesn't show that androgen deprivation therapy was responsible for diabetes, heart disease, heart attacks, or sudden death in any of the patients.
Observational studies, like this one, don't prove cause and effect.
The researchers call for more studies on the topic. They note that diabetes and heart disease become more common with age; their findings didn't change when they took that into account.