Treating prostate cancer patients with drugs that block hormonal activity does not appear to increase the risk of death from cardiovascular disease, according to a study led by Massachusetts General Hospital (MGH) researchers.
While a 2006 report from members of the same study team found that treatment with gonadotropin-releasing hormone (GnRH) agonists increased the risk of diabetes and heart disease, the current study is the first to examine whether treatment actually increased heart-disease-related deaths. In their Journal of Clinical Oncology report, which has been released online, the researchers note that GnRH agonist treatment has a number of adverse side effects, which should be kept in mind when determining treatment strategies.
"Hormonal therapy for prostate cancer has become routine for many patients, so it's even more important to understand the potential adverse effects of treatment," says lead author Jason Efstathiou, MD, DPhil, of the MGH Cancer Center and Department of Radiation Oncology. "Given recent concerns about the safety and impact on cardiac health of hormonal therapies - particularly GnRN agonists - our study is quite timely."
Since the male hormones called androgens can accelerate the development of prostate cancer, reducing their activity is a standard part of treating the disease. Most commonly this is done with GnRH agonists that block the production of all sex hormones. GnRH agonist therapy is routinely administered to men whose cancer has spread beyond the prostate gland, and its use in patients whose tumors appear confined to the prostate is becoming more common. It is estimated that one-third of the two million prostate cancer survivors in the U.S. are currently receiving this therapy, making understanding the potential adverse effects of treatment particularly important.
The earlier report from a Harvard Medical School team - including Matthew Smith, MD, PhD, of the MGH Cancer Center, who is corresponding author of the current study - found that men with localized prostate cancer who received GnRH agonist therapy had a greater risk of developing diabetes or cardiovascular disease than patients not receiving hormonal treatment. To specifically investigate the relationship between GnRH agonist therapy and death from cardiovascular disease, the current study analyzed data from a 1987-92 clinical trial run by the Radiation Therapy Oncology Group, in which almost 1,000 patients were treated for locally advanced prostate cancer with either the GnRH agonist goserelin plus radiation therapy or radiation therapy alone.