Should doctors prescribe exercise?

young woman running city park

“Although the data vary by different cancer types, there is a consistent trend suggesting that moderate daily exercise has a beneficial effect on preventing certain cancers. If you are a reasonably healthy adult, your should exercise regularly.” 

Let’s look at the relationship of exercise and selected cancers. The American Society of Clinical Oncology (ASCO) has done a nice job of summarizing:

Breast Cancer

While the amount of risk reduction varies among studies (20-80%), most suggest that 30 to 60 minutes of moderate to high-intensity exercise per day lowers breast cancer risk. Women who are physically active throughout their life appear to benefit the most, but those who increase physical activity after menopause also fare better than inactive women.1

Colon Cancer

Research suggests that people who increase their physical activity can lower the chance of developing colon cancer by 30 to 40% relative to sedentary adults.1,2 A decrease in colon cancer risk can be achieved regardless of body mass index (BMI) and people who are most active benefit the most. There is insufficient evidence of a protective effect of physical activity on the risk of rectal cancer (a protective effect was seen in some case-control studies, but not in cohort studies).3

Endometrial, Lung and Ovarian Cancer

A handful of studies have suggested that women who are physically active have a 20-40% reduced risk of endometrial cancer compared to those who don’t exercise.1 Higher levels of physical activity seem to also protect against lung cancer (up to 20% reduction in risk), particularly among men.1Although less consistent, research suggests that physical activity possibly reduces the risk of ovarian and prostate cancer.

What about Other Cancers?

While observational data on the benefits of exercise for prevention of the types of cancers listed above are fairly consistent, evidence of the effects of exercise on prevention of any other type of cancer either is either insufficient or inconsistent.2,4

Prostate Cancer

Prostate cancer is one disease in which the data are not consistent, however prostate cancer is a heterogeneous disease and risk factor associations for total non-aggressive disease are different from aggressive / lethal disease. Most population based studies show similar findings, with little effect of exercise on overall incidence of prostate cancer but lower risk of aggressive prostate cancers for those with the highest levels of VIGOROUS activity (rather than any type of activity). In the Health Professionals Follow-up Study men 65 years or older who engaged in vigorous physical activity, such as running, jogging, biking, swimming or tennis at least three hours per week  had a 67% lower risk of advanced prostate cancer and 74% lower risk of fatal prostate cancer.5

Conflicting data for other malignancies

For example, one recent study found no association between physical activity and risk of developing gastric, rectal, pancreatic, bladder, testicular, kidney and hematological cancers.4 In contrast, a pooled analysis of data from prospective trials with 1.4 million participants found that physical activity was linked to lower risk of 13 cancers: esophageal, lung, kidney, gastric, endometrial, myeloid leukemia, myeloma, colon, head and neck, rectal, bladder, and breast.6Interestingly, leisure-time physical activity was associated with a higher risk of melanoma (presumably due to time spent outdoors) and prostate cancer, although it is not clear from these data whether that association was with nonaggressive or aggressive prostate cancer.

While we wait for confirmation and clarity on the role of exercise in preventing all the 200+ types of cancer – should doctors prescribe exercise? The answer is simple: yes, because evidence of the protective role of exercise is already strong for some of the most common cancers.

References

  1. Lee I, Oguma Y. Physical activity. In: Schottenfeld D, Fraumeni JF, editors. Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press, 2006.
  2. Slattery, ML. Physical activity and colorectal cancer. Sports Medicine 2004; 34(4): 239–252.
  3. Pham NM, et al. Physical activity and colorectal cancer risk: an evaluation based on a systematic review of epidemiologic evidence among the Japanese population. Jpn J Clin Oncol. 2012 Jan;42(1):2-13.
  4. Friedenreich CM, Neilson HK, Lynch BM. Eur J Cancer. State of the epidemiological evidence on physical activity and cancer prevention. 2010 Sep;46(14):2593-604.
  5. Giovannucci E, Liu Y, Leitzmann MF, et al. A prospective study of physical activity and incident and fatal prostate cancer. Arch Intern Med. 2005; 165(9):1005-1010.
  6. Moore SC, Lee IM, Weiderpass E, et al. Association of Leisure-Time Physical Activity With Risk of 26 Types of Cancer in 1.44 Million Adults. JAMA Intern Med. 2016 Jun 1;176(6):816-25.
  7. http://www.asco.org/about-asco/press-center/asco-resources-media/cancer-perspectives/should-cancer-doctors-prescribe?et_cid=38723632&et_rid=463715101&linkid=Read+more

 

I’m Dr. Michael Hunter. Of course, the disclaimer: Do not begin an exercise program without input from an appropriate medical professional. Many can simply start with a brisk walk for 30 minutes daily, 5 days per week. Have a wonderful day!

Obesity-related Cancers on the Rise Worldwide

What You Need to Know: A quarter of all obesity-related cancers worldwide in 2012 were attributable to the rising average body mass index (BMI) in the population since 1982, and were therefore “realistically avoidable”.
 
The Study: Using data from a number of sources including the GLOBOCAN database of cancer incidence and mortality for 184 countries, Arnold and colleagues created a model to estimate the fraction of cancers associated with excess bodyweight in countries and regions worldwide in 2012, and the proportion that could be attributed to increasing BMI since 1982.
  • Obesity-related cancer is a greater problem for women than men, largely due to endometrial (womb/uterus) and post-menopausal breast cancers. In men, excess weight was responsible for 1.9% or 136,000 new cancers in 2012, and in women it was 5.4% or 345,000 new cases.
  • Post-menopausal breast, endometrial, and colon cancers were responsible for almost three-quarters of the obesity-related cancer burden in women (almost 250,000 cases), while in men colon and kidney cancers accounted for over two-thirds of all obesity-related cancers (nearly 90,000 cases).
  • In developed (very high human development index; HDI) countries, around 8% of cancers in women and 3% in men were associated with excess bodyweight, compared with just 1.5% of cancers in women and about 0.3% of cancers in men in developing countries (low HDI).
  • North America contributed by far the most cases with 111,000 cancers — equivalent to almost a quarter (23%) of all new obesity-related cancers globally — and sub-Saharan Africa contributed the least (7300 cancers or 1.5%). Within Europe, the burden was largest in eastern Europe, accounting for over a third of the total European cases due to excess BMI (66,000 cancers).

The proportion of obesity-related cancers varied widely between countries. In men, it was particularly high in the Czech Republic (5.5% of the country’s new cancer cases in 2012), Jordan and Argentina (4.5%), and in the UK and Malta (4.4%). In women, it was strikingly high in Barbados (12.7%), followed by the Czech Republic (12%) and Puerto Rico (11.6%). It was lowest in both sexes in countries within sub-Saharan Africa (less than 2% in men and below 4% in women).

The global prevalence of obesity in adults has doubled since 1980. If this trend continues it will certainly boost the future burden of cancer, particularly in South America and North Africa, where the largest increases in the rate of obesity have been seen over the last 30 years.” I’m Dr. Michael Hunter.

My Take: Currently used gene signatures (including MammaPrint and OncoType DX) are associated with the probability of distant disease recurrence and are in clinical use as prognosticators. These signatures are primarily driven by genes reflecting the amount of cancer cell proliferation and the presence (or absence) or hormone receptors in the tumor. Now we have the exciting promise of adding in characteristics of the tumor microenvironment to offer better prognoses. I think this approach represents a fundamental change in how we approach cancer. I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

 

 

Journal Reference:

  1. Melina Arnold, Nirmala Pandeya, Graham Byrnes, Andrew G Renehan, Gretchen A Stevens, Majid Ezzati, Jacques Ferlay, J Jaime Miranda, Isabelle Romieu, Rajesh Dikshit, David Forman, Isabelle Soerjomataram. Global burden of cancer attributable to high body-mass index in 2012: a population-based study. The Lancet Oncology, 2014; DOI: 10.1016/S1470-2045(14)71123-4

Sleep Apnea Linked to Cancer and Stroke Risk

CPAP sleep apnea

What You Need to Know: Moderate to severe obstructive sleep apnea isassociated with an increased risk of stroke, cancer and death.

Background: Sleep apnea is a serious sleep disorder that occurs when a person’s breathing is interrupted during sleep. People with untreated sleep apnea stop breathing repeatedly during their sleep, sometimes hundreds of times. This means the brain — and the rest of the body — may not get enough oxygen.  There are two types of sleep apnea:

  • Obstructive sleep apnea (OSA): The more common of the two forms of apnea, it is caused by a blockage of the airway, usually when the soft tissue in the back of the throat collapses during sleep.
  • Central sleep apnea: Unlike OSA, the airway is not blocked, but the brain fails to signal the muscles to breathe due to instability in the respiratory control center.

The American Academy of Sleep Medicine reports that obstructive sleep apnea is a common sleep disorder that affects up to seven percent of men and five percent of women. It involves repetitive episodes of complete or partial upper airway obstruction occurring during sleep despite an ongoing effort to breathe. The most effective treatment option for OSA is continuous positive airway pressure (CPAP) therapy, which helps to keep the airway open by providing a stream of air through a mask that is worn during sleep.

 The Study: The study involved 397 adults who are participating in the ongoing Busselton Health Study. Objective sleep data were gathered in 1990 using a portable home sleep testing device. Participants with a history of stroke or cancer were excluded from selected analyses.

The Evidence: Results of a 20-year follow-up study show that people with moderate to severe obstructive sleep apnea are

  • four times more likely to die (hazard ratio = 4.2), nearly four times more likely to have a stroke (HR = 3.7),
  • three times more likely to die from cancer (HR = 3.4), and
  • 2.5 times more likely to develop cancer.

Results were adjusted for potential confounding factors such as body mass index, smoking status, total cholesterol and blood pressure.

My Take: If you think you may have sleep apnea, get evaluated. You may need medical intervention. Are you at risk for having sleep apnea? Sleep apnea can affect anyone at any age, even children. Risk factors for sleep apnea include:

  • Being male
  • Being overweight
  • Being over age 40
  • Having a large neck size (17 inches or greater in men and 16 inches or greater in women)
  • Having large tonsils, a large tongue, or a small jaw bone
  • Having a family history of sleep apnea
  • Gastroesophageal reflux, or GERD
  • Nasal obstruction due to a deviated septum, allergies, or sinus problems

 I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad: Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

 References: Nathaniel S. Marshall, Keith K.H. Wong, Stewart R.J. Cullen, Matthew W. Knuiman, Ronald R. Grunstein. Sleep Apnea and 20-Year Follow-Up for All-Cause Mortality, Stroke, and Cancer Incidence and Mortality in the Busselton Health Study Cohort. Journal of Clinical Sleep Medicine, 2014; DOI: 10.5664/jcsm.3600; http://www.webmd.com/sleep-disorders/sleep-apnea/sleep-apnea

Smoking Linked to More Diseases

lips smoking

On the fiftieth anniversary of the first US Surgeon General’s report on smoking, researchers continue to link the practice to new diseases, and public health officials urge even more forceful efforts to bring America to the smoking “end game.”

US Department of Health and Human Services Secretary Kathleen Sebelius said, “We’ve made a lot of progress since the first Surgeon General’s report, but we’re still a country addicted to tobacco.”

The 980-page report is divided into 3 sections, starting with a historical perspective with overview and conclusions, followed by a compilation of available public and privately funded research about the health consequences of active and passive smoking and a section entitled “Tracking and Ending the Epidemic,” which provides data about smoking, along with recommendations for bringing the smoking “epidemic” to an end.

The research section is the largest, reflecting a huge accumulation of knowledge since the first Surgeon General’s report linking smoking with lung cancer. “Amazingly, 50 years in, we’re still finding out new ways that tobacco maims and kills people,” noted Thomas R. Frieden, MD, head of the Centers for Disease Control and Prevention (CDC), also speaking at the briefing.

Diabetes, rheumatoid arthritis, immune dysfunction, tuberculosis, colorectal cancer, liver cancer, age-related macular degeneration, and erectile dysfunction are among the diseases that can now be added to the ever-growing list for which evidence strongly supports a causal association with smoking. Also new on the list are orofacial clefts in the infants of women who smoke during pregnancy, as well as stroke resulting from secondhand smoke.

“Physicians may find surprising that we continue to causally link additional diseases to smoking. The list just keeps getting longer,” the report’s editor, Jonathan M. Samet, MD, told Medscape Medical News. I’m Dr. Michael Hunter.

Reference: Surgeon General’s Report Links More Diseases to Smoking; Medscape.com: http://www.medscape.com/viewarticle/819438

Where Are the Smokers? Start with Greece, Bulgaria, and Macedonia

Girl smoking outdoors

Interesting update yesterday from National Public Radio (NPR) on cigarette use.

We have reached the 50th anniversary of the landmark US Surgeon General’s report exposing the dangers associated with smoking, including lung cancer. The proportion of Americans who smoke cigarettes has dropped fairly dramatically. About 19 percent of American adults smoke these days, compared with about 42 percent in 1965. Smoking has become less prevalent in other countries, too, including Canada, Mexico and Iceland. Worldwide, smoking dropped 10 percentage points to 31 percent among men in 2012, from 41 percent in 1980. For women, it has been almost halved, falling from about 11 percent to 6 percent over the same period.

Where is smoking common? To see a global map, pleasego to: http://viz.healthmetricsandevaluation.org/tobacco/. Greece, Bulgaria and Macedonia look like the burning tip of a cigarette on the map. Russia, France and Austria aren’t far behind. Smoking has gone up recently in Sweden, Belarus and Mexico. It’s down in the U.S., Hungary and Argentina.

Bottom line: Worldwide, there were 967 million people who smoked in 2012, compared with 721 million in 1980. I’m Dr. Michael Hunter.

Reference: The numbers were crunched by The Institute for Health Metrics and Evaluation (IHME) is an independent global health research center at the University of Washington (Seattle, USA) that provides rigorous and comparable measurement of the world’s most important health problems and evaluates the strategies used to address them. IHME makes this information freely available so that policymakers have the evidence they need to make informed decisions about how to allocate resources to best improve population health.

Boost Your Immune System: Take a Walk in the Woods

Forest
Forest (Photo credit: Moyan_Brenn)

When we walk in a forest or park, our levels of white blood cells increase and it also lowers our pulse rate, blood pressure and levels of the stress hormone cortisol.

– Dr. Aaron Michelfelder

Unmanaged stress can lead to serious health conditions, including high blood pressure, heart disease, obesity, and diabetes. Now research from Japan suggests that walking in the woods may play a role in fighting cancer. Plants emit a chemical (phytoncides) that protect them from rotting and insects. When we humans breathe it in, we increase our own levels of natural killer (NK) cells, a part of a person’s immune response to cancer. In addition, our levels of white blood cells increase, and our pulses and blood pressure may lower. Finally, levels of the stress hormone cortisol can drop.

If you want to wind down, stay away from electronic screens, as they activate the mind. Try to have quite time in the hour before sleeping. And consider a walk in the woods, preferably not at night, and in a zombie-free zone (for all of my fellow Walking Dead television series fans). I’m Dr. Michael Hunter.

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad:  Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minute; Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

Maximizing Broccoli’s Cancer-Fighting Potential

broccoli

Ugh. My mother was right when she told me to eat my broccoli, kale, collard greens, and cabbage. We believe that diet can influence your risk of getting cancer. Consumption of the so-called cruciferous vegetables has been associated with a lower risk of prostate, colon, breast lung, and skin cancers.

How Does Broccoli Lower Cancer Risk? In that super food, glucosinolates (GSs) and the substances that are left behind when GSs are broken down can boost the levels of a broccoli enzyme that helps rid the body of carcinogens. What is new is that reearchers sprayed a plant hormone called methyl jasmonate on broccoli. Jasmonate is a natural hormone that protects plants againsts pests.

Researchers found that sulforaphane is the major contributor to enhancing cancer-fighting enzyme levels. Environmental conditions played a role, too. The investigators believe that this information may be used to identify superior types of broccoli and to breed even more healthful broccoli plants. I’m Dr. Michael Hunter, and even though I don’t love broccoli, I’ll be adding a bit to my lung today!

Action Point: As little as three to five servings of broccoli a week provides some protection against cancer. This is not true for frozen broccoli, but scientists are developing techniques to make frozen as nutritious as fresh (by blanching broccoli at a slightly lower temperature than industry standard (University of Illinois, 2013: Dosz EB and Jeffery EH. Journal of Food Science 2013).

The small print: The material presented herein is informational only, and is not designed to provide specific guidance for an individual. Please check with a valued health care provider with any questions or concerns. As for me, I am a Harvard- , Yale- and UPenn-educated radiation oncologist, and I practice in the Seattle, WA (USA) area. I feel genuinely privileged to be able to share with you. If you enjoyed today’s offering, please consider clicking the follow button at the bottom of this page.

Available now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Both can be found at the Apple Ibooks store. Coming Soon for iPad:  Understand Breast Cancer in 60 Minutes; Understand Colon Cancer in 60 Minuteable now: Understand Colon Cancer in 60 Minutes; Understand Brain Glioma in 60 Minutes. Thank you.

Reference: Kang Mo Ku, et al. J Agricultural and Food Chemistry, 2013.