Common Prostate Cancer Treatment May Be Less Risky Than Thought

Dec. 6, 2011 -- Just over a year ago the FDA warned that commonly used hormone-blocking treatments may increase the risk for fatal heart attacks in prostate cancer patients, but a new analysis finds these fears to be unfounded for most men.

The review, which appears this week in the Journal of the American Medical Association, found no difference in heart attack deaths and death from other heart and stroke-related causes between patients who took androgen deprivation therapy (ADT) and those who did not.

ADT treatment was associated with a lower overall risk of death from prostate cancer.

The analysis did not specifically look at groups of men with known heart disease, but the findings should reassure other prostate cancer patients who might benefit from hormone-blocking treatments, says researcher Paul L. Nguyen, MD, of Boston’s Dana-Farber/Brigham and Women’s Cancer Center.

“Our study found that for men with [high]-risk prostate cancer, this therapy saves lives,” Nguyen tells WebMD.

Health Groups Warn of Possible Risk

ADT in the form of a medication called GnRH agonist has been a mainstay of treatment for men with high-risk prostate cancer.

The treatment blocks the male hormones that fuel tumor growth. But a 2006 study first raised concerns about the safety of ADT, finding an increased risk for diabetes, heart attack, and death from heart-related causes in users.

Several more studies linking hormone-blocking therapy to heart risk in prostate cancer patients followed, but other studies have failed to show the association.

Last year, prior to the FDA warning, health groups -- including the American Heart Association, the American Cancer Society, and the American Urological Association -- issued a joint statement designed to alert doctors and patients about the therapy’s potential risks.

In the new review -- designed to examine the treatment’s safety --  Nguyen and colleagues analyzed data from eight clinical trials comparing patients who were treated with ADT to a group of patients that did not receive ADT for the treatment of high-risk prostate cancer.

The analysis included 2,200 patients treated with ADT and nearly 2,000 patients that did not take the treatment.

Fewer ADT-Treated Patients Died

Study participants were followed for as long as 15 years, with an average follow-up of about eight to 10 years.

During this time, 11% of the patients treated with ADT died of heart or blood vessel disease-related causes, compared to 11.2% of patients who did not get the treatment.

The age of the patients and how long they took the hormone therapy did not influence the findings, and men who took ADT had a 31% lower risk of dying from prostate cancer during the study than men who did not take the treatment.

They also had a lower overall risk of death, with 38% dying during the study, compared to 44% of the comparison-group patients.

“For the majority of men considering ADT for aggressive prostate cancer, these results should be reassuring,” the researchers write.

Tomaselli: Men With Heart Disease Should Be Followed Closely

The researchers add that the treatment-related risk isn’t clear for men with known heart disease or those who have had a heart attack.

American Heart Association President Gordon Tomaselli, MD, tells WebMD that the research as a whole emphasizes the importance of individualizing decisions about the use of ADT.

He adds that if the risk-benefit analysis favors using the treatment in patients with heart disease and stroke risk, these patients need to be followed very carefully to ensure that modifiable risk factors for heart attack and stroke, such as high blood pressure and cholesterol, are treated aggressively.

American Cancer Society Chief Medical Officer Otis Brawley, MD, says the most recent data on ADT treatment suggest that concerns about its use in men with existing heart disease are well warranted.

“About a third of men in the U.S. who are diagnosed with prostate cancer have a stroke at some point in their lives,” he tells WebMD. “There is an appropriate use for these treatments and an inappropriate use for them and I would be leery of using them in men who would not have qualified for these studies.”