Continuous vs. intermittent hormone therapy (IHT): No survival difference

Nancy Ferrari

Senior editor, Harvard Health

Physicians often prescribe hormone therapy to reduce testosterone levels in men with advanced prostate cancer. Without testosterone to fuel tumor growth, the cancer recedes. However, men often complain that the drugs dampen their libido, lead to weight gain, and cause fatigue, hot flashes, and breast enlargement. Some studies have shown that taking hormone therapy intermittently, rather than continuously, can improve patients’ quality of life. But does going off the medication from time to time hasten death?

According to a recent study conducted at 32 centers across Europe, the answer is no. Researchers started 626 patients on hormone therapy for three months. Patients were then randomly assigned to either intermittent or continuous therapy. Those on IHT stopped taking the drugs until their prostate-specific antigen (PSA) level rose to 10 ng/ml or greater or to 20 ng/ml or greater, depending on whether or not they had symptoms of disease progression. (Half were off therapy for at least a year.) After a median time of 14 weeks of treatment, they once again stopped taking the drugs. Those on continuous therapy never stopped treatment.

After following patients for a median time of 51 months, the researchers found that the cancer progressed a bit more quickly in men on IHT, but there was no difference in overall survival between the groups. Patients on IHT also experienced fewer side effects and had more sexual activity. Another plus: intermittent therapy could keep more money in patients’ pockets.

Given the beneficial effects and the lack of a survival difference, the researchers conclude that patients and doctors should consider IHT.

SOURCE: Calais da Silva FE, Bono AV, Whelan P, et al. Intermittent Androgen Deprivation for Locally Advanced and Metastatic Prostate Cancer: Results from a Randomized Phase III Study of the South European Uroncological Group. European Urology 2009;55:1269–77. PMID: 19249153.

Originally published Oct. 1, 2009;  last reviewed May 3, 2011.

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