Hormone blockade makes radiation therapy more effective for medium and high-risk localized prostate cancer

Improvements comparable to adding hormones to radiation for advanced-stage cancers

BOSTON September 13, 2000 -- Researchers at Brigham and Women's Hospital (BWH) and Dana-Farber Cancer Institute (DFCI) have found that combined radiation therapy (RT) and androgen suppression therapy (AST) is a more effective treatment for localized, early-stage prostate cancer compared to treatment using radiation therapy alone. The findings are published in the September 13th issue of JAMA (Journal of the American Medical Association).

"Previous studies have shown a benefit to treating advanced-stage prostate cancer with radiation and hormone therapy," said Anthony V. D'Amico, MD, PhD, of BWH and DFCI. "This is the first study to show that the combination treatment may also benefit [men] with early-stage cancer."

In the study, researchers compared the relative risk of prostate specific antigen (PSA) failure during a five-year period in men who underwent radiation therapy and androgen suppression as treatment for diagnosed early-stage prostate cancer compared with men who received RT alone..

Although no significant difference between treatment groups was found in patients in the low-risk category, men who were classified in the intermediate-risk group and received both therapies for their cancer were five times less likely to have PSA failure than men who received RT alone.

For men in the high-risk group who received both RT and AST, the effectiveness of combination therapy was more profound. They were two and one-half times less likely to have PSA failure than men who had received RT. "While further research is needed, it appears that the one-two punch of RT and AST may be a more effective treatment in the battle against both advanced-stage and early-stage prostate cancer," D'Amico said.

The 1,586 study participants were categorized using a combination of their PSA levels, biopsy Gleason score, and stage of tumor into three groups. All patients in the study had cancer that was localized to the prostate by rectal exam. The more aggressive the participant's tumor, the higher the risk category in which he was placed. The men's cancers were treated using a three-dimensional conformal RT with or without AST.

AST is a type of hormonal therapy that is often used in all phases of prostate cancer treatment to help block production or action of the male hormones that have been shown to fuel prostate cancer.

Biochemical Outcome Following External Beam Radiation Therapy With or Without Androgen Suppression Therapy for Clinically Localized Prostate Cancer Anthony V. D'Amico, MD, PhD et al, JAMA, Vol. 284 No. 10, September 13, 2000 "Our data suggest a significant benefit in 5-year PSA outcomes for men with clinically localized prostate cancer in intermediate- and high-risk groups treated with RT plus AST vs those treated with RT alone. Results from prospective randomized trials.

Dana-Farber Cancer Institute

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