Adding hormone therapy to radiation therapy has been proven in randomized clinical trials to improve overall survival for men with intermediate- and high-risk prostate cancer. However, adding hormone therapy may reduce overall survival in men with pre-existing heart conditions, even if they have high-risk prostate cancer according to a new study.

From 1991 to 2006, 14,594 men with prostate cancer were treated with brachytherapy-based radiation therapy. Of these, 1,378 (9.4 percent) had a history of congestive heart failure or myocardial infarction. Among these men with heart conditions, 22.6 percent received supplemental external beam radiation therapy and 42.9 percent received four months of androgen deprivation therapy to reduce testosterone in their bodies, which can help the cancer grow.

For the entire group of men with a history of heart problems, adding hormone therapy led to a significant increase in overall mortality. For men with pre-existing heart conditions and high-risk prostate cancer, researchers found that by 5 years, 31.8 percent of the men who received hormones had died compared to 19.5 percent of the men who did not receive hormone therapy.

"We found that for men with localized prostate cancer and a history of heart problems, treatment with hormones plus radiation was associated with a higher all-cause mortality than treatment with radiation alone, even for patients with high-risk malignant disease," Paul L. Nguyen, M.D., lead author of the study and a radiation oncologist at the Dana-Farber/Brigham and Women's Cancer Center in Boston, said. "Despite Phase III data supporting hormone therapy use for men with high-risk disease, the subgroup of men with a history of heart disease may be harmed by hormone therapy."

He added, "Future research is necessary to understand the mechanisms of this effect. In the meantime, I encourage men with prostate cancer and a history of heart disease to talk to their doctor about the benefits and risks of hormone therapy."

Source: ASTRO