Retirement-age men with slow-growing prostate cancer may wish to consider monitoring their disease rather than being treated immediately, according to a new study led by investigators at Dana-Farber Cancer Institute and Massachusetts General Hospital (MGH).

The study results, to be published in the Dec. 1 issue of the Journal of the American Medical Association, provide information to the thousands of American men in the 65-year-old age range who each year face the decision of how to deal with newly diagnosed prostate cancer when the cancer has characteristics that suggest a very low risk of spreading beyond the prostate.

Because there is limited information comparing outcomes of treatment options for low-risk disease, investigators developed a computer model simulating hypothetical patients whose quality of life and response to treatment were based on reports in medical literature.

“The analysis demonstrates that for this group of prostate cancer patients, a course of ‘active surveillance’ in which patients receive a blood test (PSA) every three to six months, a physical exam every six months, and periodic re-biopsies of their tumor tissue is a reasonable alternative to immediate treatment in terms of quality of life,” says study lead author Julia Hayes, MD, of Dana-Farber and the MGH Institute for Technology Assessment. If surveillance reveals that the cancer has become more of a threat, it can then be treated.

Every year, about 200,000 men are diagnosed with prostate cancer in the United States, 90% of whom receive immediate treatment, which can include surgery, hormonal treatment, or radiation therapy.

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However, in more than 70% of men with prostate cancer, the disease is low-risk, meaning it is unlikely to become life-threatening, and may not require immediate treatment. “In recent years, active surveillance has emerged as an alternative to initial treatment for men with this type of prostate cancer,” Hayes says.

“But, while clinical studies are under way comparing active surveillance to front-line treatment, it will be years before they yield definitive results. The computer model we created allows us to anticipate those studies’ findings, and provides information to help men and their physicians negotiate this difficult decision.”

“Our analysis showed that 65-year-old men with low-risk, localized prostate cancer who chose active surveillance had a higher quality of life than those who received surgery or radiation right away, in part because they were able to avoid or delay adverse effects of treatment,” she states.

Patients approach the decision with different sets of preferences: some may be anxious about leaving the disease untreated; others may be more concerned about the potential side effects of treatment, which can include urinary incontinence, erectile dysfunction, and bowel disturbances.

When these patient preferences were changed in the model, the results of the model changed, in some cases favoring initial treatment. Therefore, the authors urge patients to discuss these issues with their families and doctors in order to choose the approach that best reflects their own preferences and values.

In the study, researchers used a measure called Quality-Adjusted Life Expectancy (QALE) to compare active surveillance to initial treatment. “QALE takes into account both the quality and length of each patient’s life,” explains the study’s senior author, Pamela McMahon, PhD, of the Institute for Technology Assessment at MGH.

“It weighs the benefits and side effects of treatment, as well as how men feel about being treated or not being treated. It’s an attempt to capture the physical and psychological aspects of disease and its treatment as thoroughly as possible.”

One of the main surprises of the study was that active surveillance held its edge over immediate treatment from a quality-of-life standpoint even when researchers entered data into their computer model that exaggerated any negative health effects of active surveillance, Hayes says. “Thousands of men each year face the decision of whether to be treated immediately for low-risk prostate cancer or use active surveillance,” McMahon says. “Our study offers them evidence that can be a useful starting point for discussions with their families and doctors.”

The study was conducted as part of a series of comprehensive analyses of the comparative effectiveness of active surveillance versus treatment for men with low-risk prostate cancer conducted by the Institute for Clinical and Economic Review (ICER), based at MGH’s Institute for Technology Assessment.

ICER has also produced a website for low-risk prostate cancer patients based on these analyses to aid patients in their decision-making. The study was funded in part by grants from the National Cancer Institute, the U.S. Department of Defense, and the Prostate Cancer Foundation, and by funding from the Blue Shield of California Foundation.

For more information:
Thompson IM, Klotz L. Active Surveillance for Prostate Cancer JAMA. 2010 Dec 1;304(21):2373-80.

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