Should doctors prescribe exercise?

“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!

Physical Activity Increases Prostate Cancer Survival

What You Need to Know: Yet another study is confirming the benefits of physical activity following the diagnosis of cancer, this time of prostate cancer, on all-cause and prostate-specific survival. Higher levels of physical activity are associated with reduced rates of overall and prostate cancer–specific mortality.

Background: Few studies have investigated the association between post-diagnosis physical activity and mortality among men diagnosed with prostate cancer. The aim of this study was to investigate the effect of physical activity after a prostate cancer diagnosis on both overall and prostate cancer–specific mortality in a large cohort.

Methods: Data from 4,623 men diagnosed with localized prostate cancer 1997–2002 and followed-up until 2012 were analyzed. Researchers in Sweden examined the association between post-diagnosis recreational MET-h/d, time spent walking/bicycling, performing household work or exercising, and time to overall and prostate cancer–specific death. All models were adjusted for potential confounders.

Results:

  • Men who walked or cycled for 20 minutes a day or more had a 30% lower risk for all-cause mortality and a 39% decreased risk for prostate cancer–specific mortality compared with men who walked or cycled less than 20 minutes a day, investigators report.
  • For those exercising 1 or more hours a week, all-cause mortality was reduced by 26% and prostate cancer–specific mortality by 32% compared with men who reported exercising less than 1 hour a week.
  • After considering all time spent walking, cycling, exercising, and doing household work, researchers found that all-cause mortality was 37% lower while prostate cancer–specific mortality was 22% lower for men who had a total MET of 5 or more hours a day compared with those who had a total MET of less than 5 hours a day.

 

Activity After Prostate Cancer Diagnosis Overall Mortality Prostate Cancer–Specific Mortality
  Walking/cycling <20 min/day vs ≥20 min/day 0.70 0.61
  Household work <1 h/day vs ≥1 h/day 0.71 0.86
  Exercise < 1 h/wk vs ≥1 h/wk 0.74 0.68

Conclusions: Higher levels of physical activity were associated with reduced rates of overall and prostate cancer–specific mortality.

Impact: This study further strengthens previous results indicating beneficial effects of physical activity on survival among men with prostate cancer.

Reference: Cancer Epidemiol Biomarkers Prev; 1–8. ©2014 AACR.

Aspirin May Reduce Your Risk of Prostate Cancer

What You Need to Know: A recent meta-analysis (study of a group of studies) demonstrated an association between aspirin use and a reduced risk of prostate cancer.

Background: Anti-inflammatory medications lower prostate-specific antigen (PSA) levels; therefore, whether these findings reflect reduced prostate cancer detection or lower risk of the disease is not known.

The Study: Researchers tested the association between aspirin and non-aspirin nonsteroidal anti-inflammatory drug (NSAID) on prostate cancer diagnosis in the REDUCE trial, where all men underwent biopsy at 2- and 4-years largely independent of PSA. The researchers examined the association between aspirin, NSAID, or both and total, low-grade (Gleason <7) prostate cancer, or high-grade (Gleason ≥7) prostate cancer vs. no prostate cancer using multinomial logistic regression among 6,390 men who underwent on-study biopsy one or more times. Overall, 50% of the men were nonusers, 21% used aspirin, 18% used NSAIDs, and 11% of the men used both.

Results: In multivariable analyses, aspirin was associated with reduced total prostate cancer risk, but use of NSAID or NSAIDs and aspirin was not associated with reduced risk of prostate cancer. Therefore, we created a dichotomous variable of aspirin and/or NSAID user vs. not. On multivariable analysis, the use of aspirin and/or NSAID was significantly associated with decreased total and high-grade (dangerous-type) prostate cancer risk, but not with risk in low-grade prostate cancer.

My Take: While I cannot make an across-the-board recommendation for everyone to take aspirin (we do not have high0level evidence to support doing so; in addition, there are potential serious risks associated with the use of NSAIDs and/or aspirin), I envision a future in which decisions will be individualized. We will look at your risk of heart disease, stroke, prostate and colon cancer as well as potential side effects such as stomach bleeding. I’m Dr. Michael Hunter, and I take a baby (81mg) aspirin daily (my dad had a stroke at 85 years-old).

Reference: Clinical Cancer Research, 12/18/2014 Clinical Article

Want To Stay Young? Start Moving.

women walking exercise

A new study finds that exercise among older adults helps ward off depressiondementia and other health problems, such as heart diseasecancer and diabetes. Exercise increased the odds of healthy aging as much as sevenfold, the researchers found. And apparently it’s never too late to start: Even adults who don’t begin exercising until they’re older could increase their odds of healthy aging threefold, the researchers said.

“In a growing elderly population, it is important to encourage healthy aging. Physical activity is effective in maintaining health in old age,” said lead researcher Mark Hamer, from the department of epidemiology and public health at University College London, in England.

For the study, Hamer and his colleagues collected data on nearly 3,500 people with an average age of 64 who took part in the English Longitudinal Study of Aging.

As part of the study, the participants reported their level of physical activity every two years between 2002-’03 and 2010-’11. The researchers categorized the participants by how much exercise they did each week. There were those who were inactive, those who did moderate exercise and those who exercised vigorously.

People who partook in moderate or vigorous physical activity at least once a week were three to four times more likely to be healthy agers, compared with those who remained inactive, the researchers found. Moreover, people who were active at the start of the study were seven times more likely to be healthy agers than people who were inactive and remained so, the researchers found.

My Take: Want to stay healthy? Get moving. 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.

Reference: The report was published online Nov. 25 in the British Journal of Sports Medicine.

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.

Can A Healthy Lifestyle Reverse Aging? Yes!

Telomere
Telomere (Photo credit: Wikipedia)

Wow. A program of healthy eating, exercise, and stress reduction can not only reverse some diseases – it may slow down the aging process as well. This headline certainly got this 50-year-old’s attention.

How: Lifestyle changes can affect the telomeres – little brush-like caps on the end of the chromosomes that carry your DNA. A team from the University of California, San Francisco just published a small series, based on men with prostate cancer. The research showed that men who switched to a vegan diet, added exercise, and stress reduction had longer telomeres. Drs. Ornish and Blackburn led a team that examined 10 patients with prostate cancer (who had no traditional treatment).

The program includes eating a diet high in whole foods, fruits, vegetables, unrefined grains, and keeping fat to 10% of calories. The men also exercised, walking at least 30 minutes a day, 6 days per week. They did yoga-based stretching end breathing exercises, practiced relaxation techniques, and had weekly one-hour stress-reduction group sessions. And they gave blood samples. About 85-95% of patients were compliant with the program.

Wow: This is the first study showing that an intervention (of any type) can reduce cellular aging. Telomerase levels increased by 30% in just 3 months. Telomerase is an enzyme that affects telomeres. They also looked at gene activity: Of 500 genes that changed, in every case it was in a beneficial way. Five years later, they drew more blood. The telomeres were an average of 10% longer. Of 25 men who did not follow the program, the telomeres were 3% shorter than average.

My Take: Dr. Ornish’s diet has been shown to reverse heart disease, diabetes, and may help keep early prostate cancer in check. Even if you or I can’t do everything the study participants did, we all can aim in that direction. I’m Dr. Michael Hunter, and I am excited to share the good news with you!

There are many problems with the study:

This was not a randomized trial. Patients in the treatment group agreed to intense and highly demanding lifestyle changes. They were compared with a group who had similar risk factors but who clearly did not share their high level of motivation. There is no way to know what other important differences might exist between the two groups.

This was a very small trial. The original 2008 trial enrolled 30 patients– there were no controls– and 24 patients had sufficient blood samples to assess telomerase activity. In the new report only 10 patients had adequate blood samples available for analysis. This limits the generalizability of the study.

What caused the changes (if there were changes)? The Ornish program is contains several interventions, including drastic reductions in dietary fat and sugar, significant increases in exercise , as well as yoga classes and group therapy. There is no way to know the relative importance, of any of the individual elements of his program.

Do we have to go vegetarian or super low fat? (I doubt it) It is entirely possible that other healthy interventions might similarly change telomere length favorably. Might a Japanese diet? Mediterranean diet? South Beach diet? And what about vigorous regular exercise (here, we have Canadian data linking it to telomere stabilization, as I recall). It is entirely possible that other, completely different interventions would have a similar effect.

Might other factors lengthen life? We know a big indicator of length of life among men over the last 100 years has been work. Keep working…

So, no. I am not foolish enough to believe that a 10 person trial proves anything. (Although it can be helpful: Hodgkin’s original observation in the 1830s of adenopathy had only a dozen or so patients included, pointed the way to some of the most extraordinary progress in the cancer business ever.) . Prospective, randomized trials will need to be conducted to provide high level evidence, and the authors make this very clear in their conclusions. For now, however, we have one more brick in the wall… As for me, I’ll stick to healthy living (hopefully with a few more fruits!). And choosing my parents well (Go mom: pushing 80 and still walking 4 miles daily, and close to her weight from 40 years ago; Go dad: pushing 85, and not a single significant health problem. Still not as good as my in-laws, who all lived 94-102 years, seemingly healthy ’til the very end).

That’s my 2 cents.

Want to Try It? The men on the study followed a program advocated by Dr. Dean Ornish, an expert who has long been an advocate of very low-fat, vegetarian diet in improving health. Dr. Ornish worked with the telomere expert (and 2009 Nobel Prize winner) Dr. Elizabeth Blackburn.

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: Lancet Oncology, 2013

Can Orange Juice Reduce Your Risk of Cancer?

orange juice splashing

Background: Who amongst us doesn’t love a nice, cold glass of orange juice at breakfast? Orange juice has many potential positive anti-cancer effects , particularly because it is high in antioxidants from flavonoids such as hesperitin and naringinin. Evidence from previous laboratory studies has indicated that orange juice might reduce the risk of leukemia in children, and may aid in chemoprevention against breast, liver, and colon cancers.

The Study: In a review article in Nutrition and Cancer: An International Journal, researchers review the available evidence that links orange juice with cancer chemoprevention. The review article, “Orange Juice and Cancer Chemoprevention” discusses the putative mechanisms involved in the process, the potential toxicity of orange juice, and the available data in terms of evidence-based medicine.

This review article summarizes several biological effects of orange juice that might contribute to chemoprevention, including antioxidant, anti-mutation,  and antigenotoxic, cell protective, hormonal, and cell signaling modulating effects. Orange juice has antimicrobial and antiviral action and modulates the absorption of xenobiotics. “Orange juice could contribute to chemoprevention at every stage of cancer initiation and progression,” the researchers explained.Among the most relevant biological effects of OJ is the juice’s antigenotoxic and antimutagenic potential, which was shown in cells in culture and in rodents and humans.”

My Take: This study is hypothesis -generating: Orange juice may have significant anti-cancer effects associated with it. It does not provide high-level evidence to prove it. The authors rightfully point out the dangers of too much of a good thing:  Consumed in excess amounts — especially for children, hypertensive, kidney-compromised, and diabetics – OJ can cause noxious effects, including hyperkalemia (blood levels of potassium that are too high), and has been associated with both food allergies and bacterial outbreaks in cases where the juice was unpasteurized. “Excessive intake of any food, even for the healthiest, can lead to oxidative status imbalance,” write the researchers. Still, OJ looks promising, and I really hope that additional research is done to determine the optimal amount of orange juice for cancer chemoprevention. As for me, I’m heading for my daily glass of OJ with breakfast!

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.