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According to results presented at the 45th annual meeting of the American Society for Therapeutic Radiology and Oncology, intermittent hormone therapy appears to be a feasible treatment option for patients with prostate cancer that has recurred following radiation therapy.

Prostate cancer is the second leading cause of cancer deaths in men in the United States. However, when caught early, long-term survival is common. Standard treatment approaches for prostate cancer include radiation therapy, surgery, hormone therapy and/or watchful waiting. Prostate cancer is stimulated to grow by male hormones, particularly testosterone. One treatment approach, referred to as hormone therapy or androgen suppression, works by inhibiting growth stimulatory effects of male hormones on cancer cells. Unfortunately, patients ultimately become resistant to the effects of hormone therapy, and are considered to be hormone refractory. Since hormone therapy is often an integral part of treatment for prostate cancer, particularly cancer that has spread from its site of origin, researchers are ways to prevent cancer cells from becoming resistant to the effects of hormone therapy.

Intermittent androgen suppression (IAS) has been evaluated in the treatment of patients with prostate cancer. IAS is a type of hormone therapy in which treatment is given for a short duration, and then stopped for a given duration. IAS can then be repeated. However, optimal timing of IAS in terms of duration of a patient being on and off treatment has not been determined. Clinical trials are currently being conducted to directly compare IAS to continuous hormone therapy in the treatment of prostate cancer; however, results from these trials are still years away. The rationale behind the approach of IAS include the possibility of reducing side effects of continuous hormone therapy, such as osteoporosis, fractures, decreased sexual function, anemia and weight gain. In addition, IAS may delay resistance to hormone therapy in the course of treatment and drastically reduce medical costs.

Researchers from the Ottawa Regional Cancer Center recently conducted a clinical trial evaluating IAS in the treatment of patients with prostate cancer that has recurred following radiation therapy. The trial involved 95 patients who were treated with the hormone agents Lupron and Nilutamide. Patients received initial hormone therapy for 8 months, and again if their cancer progressed, as determined by a PSA rise of over 10 ng/ml or apparent tumor growth. The average time that patients had stabilized disease and were off hormone therapy was 9 months. The average duration time for patients to develop resistance to hormone therapy was 4 years. Testosterone rose to normal levels in 61% of patients, and anemia was improved in half of the patients.

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The researchers concluded that IAS was a feasible treatment option for patients with prostate cancer who had a recurrence following radiation therapy. Results from clinical trials directly comparing IAS to standard continuous hormone therapy are eagerly awaited; however, IAS appears to provide effective treatment with fewer side effects than continuous hormone therapy. Patients with prostate cancer that has recurred following radiation therapy may wish to speak with their physician about the risks and benefits of IAS or participation in a clinical trial further evaluating IAS or other novel therapeutic approaches. Two sources of information regarding ongoing clinical trials include the National Cancer Institute ( and Personalized clinical trial searches are also performed on behalf of patients at

Reference: Malone S, Remco D, Gad P, et al. Mature Phase II Study of Intermittent Androgen Suppression (IAS) in Prostate Cancer (PC): Efficacy and Long-Term Effect Profile. Proceedings of the 45th Annual Meeting of the American Society for Therapeutic Radiology and Oncology. International Journal of Radiation Oncology Biology Physics. 2003;57, Number 2, Supplement, Abstract Number 84:S174.

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