"A critical weekly review of important new research findings for health-conscious readers..."
By, Robert A. Wascher, MD, FACS
The information in this column is intended for informational purposes only, and does not constitute medical advice or recommendations by the author. Please consult with your physician before making any lifestyle or medication changes, or if you have any other concerns regarding your health.
EXERCISE & PROSTATE CANCER RISK
Prostate cancer is the most commonly diagnosed cancer in men, and the second most common cause of cancer-associated death in men. In 2009, an estimated 192,000 men will be diagnosed with prostate cancer, and more than 28,000 will die from this disease. Based upon current trends, 1 in 6 males will go on to be diagnosed with prostate cancer during their lifetimes.
While several different risk factors have been implicated in the development of prostate cancer, male gender, increasing age, and being an African-American male are the three most important known risk factors for this disease. As none of these major risk factors can be eliminated, it is unlikely that prostate cancer can be completely eliminated, either. However, there is some clinical evidence to suggest that specific lifestyle and dietary modifications may reduce the risk of developing prostate cancer. One lifestyle factor that has previously been proposed to potentially reduce prostate cancer risk is exercise. However, the results of previous clinical research studies have provided contradictory evidence regarding the role of exercise in prostate cancer prevention.
An intriguing new clinical research study, just published in the Journal of Urology, raises the possibility that regular aerobic exercise may, indeed, be associated with a decreased risk of developing prostate cancer. In this study, 190 men who were undergoing prostate gland needle biopsy completed a validated lifestyle and exercise history questionnaire. Statistical adjustments were then made for known prostate cancer risk factors, including age, ethnic race, body weight, prostate specific antigen (PSA) levels, family history, and digital rectal examination (DRE) findings.
The authors of this study found that the men who exercised regularly (at least 9 METS, or metabolic-equivalent task hours, per week), when compared to the men who did not regularly exercise, had a markedly lower risk of prostate cancer. In fact, the men who vigorously and regularly exercised had a whopping 65 percent lower risk of prostate cancer when compared to the men who lived sedentary lives. Additionally, even moderate levels of exercise (3 to 8.9 METS per week) were associated with a lower risk of aggressive high-grade prostate tumors among the men who were diagnosed with prostate cancer (86 percent risk reduction for high-grade tumors).
While this rather small clinical study raises the possibility that high levels of aerobic exercise throughout the week may significantly decrease the risk of prostate cancer (and may decrease the likelihood of high-grade tumors in men who are diagnosed with prostate cancer), a larger prospective, randomized clinical research trial, with long-term follow-up, will be necessary to confirm the results of this small study. Small studies, such as this one, may come to erroneous conclusions due to their small sample size, and their limited follow-up of patients. Moreover, all survey-based research studies, such as this one, are susceptible to potential biases. Finally, this study’s finding that exercise reduces prostate cancer risk may only be indirectly true, as other dietary or lifestyle factors that are more common among men who exercise regularly may actually be responsible for the decreased prostate cancer risk observed in this clinical study. Having listed all of these disclaimers, we know, without a doubt, that regular aerobic exercise improves overall health and decreases the risk of premature death. Thus, there are many good reasons to engage in regular exercise, including the possibility that doing so might reduce your risk of developing prostate cancer.
Disclaimer: As always, my advice to readers is to seek the advice of your physicianbeforemaking any significant changes in medications, diet, or level of physical activity
Dr. Wascher is an oncologic surgeon, a professor of surgery, a widely published author, and a Surgical Oncologist at the Kaiser Permanente healthcare system in Orange County, California
(Anticipated Publication Date: March 2010)
(Click above image for TV36 interview of Dr. Wascher)