In men with localized but aggressive prostate cancer, the combination of testosterone-lowering therapy and radiation improves survival substantially more than radiation therapy alone. But testosterone-lowering therapy isn’t so hot for the heart, reports the April issue of the Harvard Heart Letter. Low testosterone can increase harmful LDL cholesterol, blood sugar, blood pressure, and weight. It can also make arteries stiffer, promote formation of artery-clogging plaque, and allow blood clots to form more readily.

Preliminary results show that testosterone-lowering therapy is associated with more diabetes, more heart disease, and earlier heart attacks. However, this hormone therapy does have a significant benefit in curing prostate cancer. For instance, one study of patients with localized but unfavorable prostate cancer found that about 90% of otherwise healthy men who underwent radiation and hormone therapy were still alive after eight years, compared with about 65% of those who had only radiation therapy. The reverse was true among those with moderate or severe health problems in addition to their prostate cancer: only about 25% of those who underwent the combination were still alive, compared with 55% of those who had radiation alone.

These findings don’t mean hormone therapy should be off limits. Quite the contrary—suppressing testosterone is a life-prolonging addition to radiation therapy for men with locally advanced prostate cancer or cancer that has spread. The Harvard Heart Letter suggests that hormone therapy be used with caution in men who have had a heart attack or who are at high risk for cardiovascular disease.