New ASCO/AUA guideline recommends men and their doctors discuss using 5-ARIs to reduce prostate cancer risk

A newly released joint guideline produced by the American Society of Clinical Oncology (ASCO) and the American Urological Association (AUA) recommends that healthy men who are screened regularly for prostate cancer and show no symptoms of the disease should talk to their doctors about using a 5-alpha reductase inhibitor (5-ARI) to prevent the disease. 5-ARIs lower the level of the hormone dihydrotestosterone (DHT), which can contribute to the growth of prostate cancer. This guideline aims to provide a useful tool for clinicians and their patients in making an informed decision about the potential benefits and risks of taking 5-ARIs for preventing prostate cancer and examines the use of 5-ARIs as a method of "chemoprevention" for prostate cancer. Chemoprevention is the use of a natural, synthetic or biologic substance to reverse, suppress or prevent the development of cancer. Currently, 5-ARIs are used to treat other non-cancerous conditions, such as male-pattern baldness and benign prostatic hyperplasia.

Prostate cancer is the most common non-skin cancer among men and the second-leading cause of cancer death in men. "Although one in every six men in the United States will be diagnosed with prostate cancer, we are not recommending that all men take 5-ARIs," said Barnett S. Kramer, MD, MPH, Associate Director for Disease Prevention at the National Institutes of Health and co-chair of the guideline panel. "However, we would encourage men to begin a dialogue with their doctors to determine if they could benefit from taking 5-ARIs to reduce their prostate cancer risk."

The key recommendations in the guideline include:

• Men with a prostate-specific antigen (PSA) score of 3.0 or below who are screened regularly (or plan to get yearly PSA tests) and currently show no signs of prostate cancer are encouraged to talk with their doctor about the risks and benefits of taking a 5-ARI to further prevent their likelihood of getting prostate cancer
• Men who are already taking a 5-ARI for other conditions should talk to their doctor about continuing to use this drug for the prevention of prostate cancer

The ASCO/AUA recommendations on chemoprevention for prostate cancer are based on evidence gathered from clinical trials, including the Prostate Cancer Prevention Trial (PCPT), in which participating men took a 5-ARI for one to seven years. Trial data showed an overall relative risk reduction of approximately 25 percent in most men who took a 5-ARI to prevent prostate cancer.

"Although a large clinical trial has shown that 5-ARIs can decrease the incidence of prostate cancer, we are still not able to determine if the mortality from prostate cancer is reduced," said Paul F. Schellhammer, MD, a past president of the AUA and co-chair of the panel that developed the guideline. "However, the demonstrated effect of 5-ARIs in reducing prostate cancer incidence makes it reasonable to recommend them for use to prevent the disease. But, as with any drug, patients should discuss the risks and benefits with their physicians."

In conjunction with this guideline, ASCO developed a Decision Aid Tool, which uses straightforward charts and diagrams to explain the risks and benefits of 5-ARIs to patients and their families. One section, called "Thinking It Over," encourages patients to discuss potential treatment decisions with their doctors and their family and determine what risks and benefits matter most to them.

The guideline will be published in the March issue of the Journal of Clinical Oncology and the March issue of The Journal of Urology®. Along with the new guideline and the Decision Aid Tool, ASCO has released a corresponding patient guide available on ASCO's patient Web site, www.cancer.net.

Source: American Urological Association