February 24, 2007 /BOSTON/ Androgen deprivation therapy -- one of the most common treatments for prostate cancer -- may increase the risk of death from heart disease in patients over age 65, according to a new study by researchers at Dana-Farber Cancer Institute, Brigham and Women's Hospital and other institutions.
The goal of ADT is to block the level of circulating androgens (male hormones), which can fuel the growth of prostate cancers. "Androgen deprivation therapy is associated with elevated body mass index, increased body fat deposits and diabetes, all of which raise the risk of death from heart diseased," explains the study's lead author, Henry Tsai, MD, a resident physician at Dana-Farber, Brigham and Women's and the Harvard Radiation Oncology Program.
Although the findings need to be confirmed in clinical trials, the study authors state that oncologists should weigh the benefits of androgen deprivation therapy, or ADT, against the risk of heart problems in older prostate cancer patients.
Charles E. Myers M.D., a medical oncologist and retired NCI researcher who has himself been treated for prostate cancer, commented: "Hormonal therapy does increase systolic blood pressure and insulin resistance, but any physician with any understanding of hormonal therapy should treat increasing blood pressure and insulin resistance if it develops. Also, the same Mediterranean heart healthy diet that markedly lowers the risk of heart disease also appears to lower the risk of prostate cancer progression. "
For Men Over 65, Risk Increases With Time on Hormonal Blockade Drugs
A large study published last fall found that androgen deprivation therapy for prostate cancer puts men at increased risk for diabetes as well as for cardiovascular disease. Now Dr. Tsai's team, drawing on a national registry of men with prostate cancer (CAPSURE) , has compared the number of cardiac-related deaths among 735 men with localized prostate cancer who received ADT and among 2,901 men with the disease whose treatment did not include ADT.
After factoring in other known risks for cardiovascular disease (such as diabetes, hypertension, body mass index and smoking), researchers found that the longer patients received ADT, the sooner they were likely to die from heart disease. When the researchers analyzed the data by patients' age, the link between ADT use and death from heart disease was significant in patients over age 65, but not in those under 65. After five years, 3 percent of older men who received androgen deprivation therapy died of cardiac causes, compared with only 0.9 percent of men who did not receive the therapy.
"These findings should help oncologists determine which older patients are the best candidates for ADT," Tsai remarks. "If a patient is at high risk of cardiovascular disease, it would be advisable for an oncologist to discuss the pros and cons of ADT treatment with him before proceeding on a course of treatment."
"Although our findings demonstrated that older men receiving this treatment may be at increased risk, even after taking into account other cardiovascular risk factors, a prospective clinical trial would be needed to confirm a cause-and-effect relationship."
The researchers presented their study at the Prostate Cancer Symposium in Orlando, Fla., on Saturday, Feb. 24. The symposium is sponsored by the American Society of Clinical Oncology, the American Society for Therapeutic Radiology and Oncology and the Society of Urologic Oncology.
