Sweating Can Help Reduce Risks Of Prostate Cancer

Prostate cancer is the leading cancer health risk for men with new cases being diagnosed every three minutes. At the same time, lifestyle habits can have an enormous impact on our lives and may be the key to reducing these risks.

More specifically, research shows that there are a number of lifestyle factors that are associated with the risks of men developing a lethal type of prostate cancer. Now a new study reveals that adherence to a healthy lifestyle, particularly high physical activity and vigorous exercise, can help to lower these risks.

Led by the assistant professor of urology at the UCSF School of Medicine, Stacey Kenfield, ScD (see above right with her colleague June Chan, left), the new study utilized data from two previous US research studies, effectively tracking the men for more than 20 years. These studies were:

1. The Health Professionals Follow-up Study (HPFS) 1986-2010
2. The Physicians’ Health Study (PHS) 1982-2010

How the New Study Worked

What researchers did was to develop a lifestyle score for the 42,701 participants in the HPFS and then apply this to the 20,324 participants in the PHS. Points were scored for:

• Non smokers or those who had quit no less than 10 years before
• A body mass index (BMI) of less than 30 kg/m²
• Intense physical activity that was considered vigorous
• A diet that included lots of fatty fish and tomatoes
• A diet that did not include much processed meat

The study used the multivariable Cox proportional hazards regression to do an assessment of the risks of lethal prostate cancer. This result was adjusted to allow for “potential risk factors.” To reduce the possibility of errors, the men in the studies had to be free of diagnosed cancer.

The overall results were published in the Journal of the National Cancer Institute late last year (2015). These showed that there had been 576 lethal prostate cancer “events” in the HPFS group and 337 in the PHS group. Those who scored five to six (rather than zero to one) points in the HPFS group were estimated to have a 68 percent decreased risk of the lethal form of prostate cancer. This statistic was much lower (38 percent) in the PHS group. When only dietary factors were considered, participants scoring three points were found to have a 46 percent decreased risk (HPFS) and 30 percent decreased risk (PHS).

What the Study Tells Us

According to information released by the University of California San Francisco’s news center, the study tracked men in midlife and older for more than 20 years. Ultimately, it revealed that those who did vigorous exercise and followed other “healthy lifestyle habits” (listed above) could cut the risks of developing lethal prostate cancer by as much as 68 percent.

Commenting on the study, Kenfield said that they had estimated if men over the age of 60 had at least five healthy habits, almost half (47 percent) of lethal prostate cancer cases would have been prevented. And if men over 60 exercised at least three hours a week, “to the point of sweating,” more than a third (34 percent) of these cases could have been avoided.  

Most types of prostate cancer are “clinically indolent,” which means that they don’t metastasize and are therefore not life threatening. But when men suffer from the aggressive lethal type, the cancer generally invades body organs and bone, and is usually fatal.

Additionally, they found that eating tomatoes at least seven times a week and fatty fish once a week, could cut lethal prostate cancer by 15 and 17 percent respectively. A reduction in consumption of processed meat would cut the incidence of lethal prostate cancer by 12 percent.

Perhaps ironically, smoking was linked to only 3 percent because most older men in the US are understood to be long-term non-smokers.

About Prostate Cancer Research

One of the primary concerns about prostate cancer is that many men are subjected to treatment that isn’t necessary. Even though death rates have declined by 40 percent in the past two decades, screening is controversial because doctors cannot reliably identify which tumors will progress and which are low risk, and won’t be life-threatening. The problem is that this lack of knowledge leads to uncertainly and anxiety in both patients and their physicians, often resulting in low-risk, indolent types of prostate cancer being over-treated. Of course the anxiety can also impact negatively on patient health.  

Other Prostate Cancer Studies

Kenfield’s study is not the first to combine the effects of lifestyle, diet and exercise.

A 2007 study looked specifically at dietary and nutritional methods that could be used to slow the progression of prostate cancer in patients who opted not to have treatment. Researchers studied 23 men aged between 43 and 74 who had been diagnosed (via biopsy) with prostate cancer. They were put onto a modified Mediterranean diet and given a nutritional prostatitis supplement to take. The diet involved avoiding red meat, eggs and dairy food. Soy was also excluded from the diet and pasta was limited. They were encouraged to use virgin olive oil and to eat lots of fresh fruit and cruciferous vegetables (including broccoli, Brussels sprouts, cabbage, cauliflower and kohlrabi, all of which are brassicas) as well as Omega 3 fatty acids, fish, tomatoes and red wine. The supplement contained vitamins C, B6 and E as well as zinc and selenium, amino acids, and several herbs including Echinacea, gatlic, ginkgo biloba, stinging nettle, pumpkin seed, Saw palmetto, and Pygeum africanum.

Prostate-specific antigen (PSA) is a recognized marker of prostate cancer and so it was PSA that was used to validate the results of the study. Remarkably, 87 percent of the men were found to have a 58 percent reduction in PSA over a 13 to 84 month period.

Another study that involved men who had opted not to have treatment aimed to show how intense lifestyle changes – including a vegan diet and frequent exercise – could slow the growth of the cancer. After a year most of the participants had a slight drop in their PSA level.

Other studies have shown that drinking pomegranate juice or extract slow the cancer after radiation or surgery. Another showed flaxseed taken daily to have a similar effect.

Typically studies focus on different elements relating to prostate cancer, nutrition and lifestyle being one of these. Other specific topics include:

• Prevention with researchers looking for foods that may lower risks of prostate cancer. The lycopenes in tomatoes and isoflavones in soybeans are thought to be useful preventatives. Some vitamins are recommended (including C, B6 and E,) but research studies have reported contradictory results.
• Early detection to catch tumors before they cause health problems. It is currently thought that the Color Doppler Ultrasound might produce more accurate prostate biopsies.
• Diagnostic solutions that are more reliable than existing diagnoses.
• Treatments including surgery and radiation that is more effective than existing treatments and therapies. One of the newest treatments being used for early stage cancer is High-Intensity Focused Ultrasound (HIFU) that destroys cancer cells by heating them with ultrasonic beams.
• Staging that helps determine treatment options. This includes Enhanced MRI and the newer Positron-Emission Tomography (PET) scans.
• Therapies including hormones, chemotherapy drugs, and immunotherapy that relies on special vaccines. Currently a large study is looking at the use of PROSTVAC that contains a genetically modified virus that contains PSA. According to the American Cancer Society, early results are promising as the body’s immune system recognizes the virus and begins to destroy the cancer cells containing PSA.

In 2013, UCSF won a $9.5 million federal grant (for study over three years) aimed at transforming and revolutionizing prostate cancer treatment. There are at least 10 specialists in the team, including Kenfield. The principal investigator of this new study is Dr Peter R. Carroll, co-director of urologic cancer at UCSF’s Helen Diller Family Comprehensive Cancer Center and professor of the UCSF Department of Urology. The co-principal director is June M. Chan, who works closely with Kenfield.

Stacey Kenfield

A seasoned researcher, Dr Kenfield has worked in the field of cancer epidemiology for the past nine years. During this time, she was part of the HPFS team that was incorporated in the new study. She is particularly interested in the relationship between physical activity and prostate cancer survival, recurrence and mortality. She has co-authored 50 studies, and has been lead author of 11 of them. Most studies focused on cancer of some sort, primarily prostate cancer.