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!

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!

Doe Exercise Really Make You Smarter?

What You Need to Know: Recently, some scientists have begun to question whether the apparently beneficial effects of exercise on thinking might be a placebo effect. The benefits of aerobic exercise are not a placebo effect.

Background: Exercise seems to be good for the human brain, with many recent studies suggesting that regular exercise improves memory and thinking skills. Studying this issue is challenging, as there is no placebo for exercise and no way to blind people about whether they are exercising.

Study: An interesting new study asks whether the apparent cognitive benefits from exercise are real or just a placebo effect – that is, if we think we will be “smarter” after exercise, do our brains respond accordingly? Researchers at Florida State University (USA) came up with a clever way to evaluate this: They focused on expectations, on what people anticipate that exercise will do for thinking. If people’s expectations jibe closely with actual benefits, then at least some of the improvements are probably a result of a placebo effect (and not exercise).

Researchers asked half of the study population to estimate how much stretching and toning (three times per week) might improve various measures of thinking, including memory and multitasking. The other volunteers were asked the same questions, but about a regular walking program. In actual experiments, stretching and toning have little if any impact on cognitive skills. Walking, on the other hand, improves thinking. But the survey respondents believed the opposite, estimating that the stretching and toning program would be more beneficial for the mind than walking.

The results from the study suggest that the benefits of aerobic exercise are not a placebo effect. This study was small and involved a self-selected group of people who like completing online surveys. Still, the data suggest exercise really does change the brain and may improve thinking. We should now turn to 1) looking more closely, at a molecular level, at how exercise remodels the brain; and 2) get more of us to exercise. 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: NY Times 25 November 2014

Can African-American Women Reduce Their Breast Cancer Risk?

What You Need to Know: High levels of vigorous exercise or brisk walking may be associated with a reduction in incidence of breast cancer in African American women.

Background: Physical activity has been associated with reduced risk of breast cancer. However, evidence on the association in African Americans has been limited.

The Study: Using prospective data from the Black Women’s Health Study, researchers assessed vigorous exercise and walking in relation to incidence of invasive breast cancer overall (n=1,364), estrogen receptor–positive (ER+, n=688) cancer, and estrogen receptor–negative (ER–, n=405) cancer, based on 307,672 person years of follow–up of 44,708 African American women aged 30 or older at enrollment.

Results: This prospective study found that high levels of vigorous exercise or brisk walking may be associated with a reduction in incidence of breast cancer in African American women.

  • Vigorous exercise at baseline was inversely associated with overall breast cancer incidence (p trend=0.05): the IRR for ≥ 7 hour/week relative to < 1 hour/week was 0.74 (95% CI 0.57–0.96).
  • The association did not differ by ER status.
  • Brisk walking for ≥ 7 hours/week was associated with a reduction similar to that for vigorous exercise.
  • Vigorous exercise at age 30, age 21, or in high school was not associated with breast cancer incidence.
    Sitting for long periods at work or watching TV was not significantly associated with breast cancer incidence.

My Take: You can reduce your risk of breast cancer by about a quarter by simply walking briskly on a regular basis. Aim for an hour a day. Now, go do it! 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: Rosenberg et al. Cancer Epidemiology, Biomarkers & Prevention. Cancer Epidemiol Biomarkers Prev. 2014 Aug 7. [Epub ahead of print]

Sports Reduces Breast Cancer Risk

Seniors jogging exercise on forest woods road

Practising sport for more than an hour day reduces the risk of contracting breast cancer, and this applies to women of any age and any weight, and also unaffected by geographical location, according to research presented to the 9th European Breast Cancer Conference (EBCC-9). Compared with the least active women, those with the highest level of physical activity reduced their risk of breast cancer by 12%, researchers say.

The Study: Professor Mathieu Boniol, Research Director at the International Prevention Research Institute, Lyon, France, recently reported the results of a meta-analysis (study of a group of studies) of 37 studies published between 1987 and 2013, representing over four million women. “These are all the studies looking at the relationship between physical exercise and breast cancer risk that have been published to date, so we are confident that the results of our analysis are robust,” he said.

The Evidence: Although the results varied according to tumour type, the overall message was encouraging, the researchers say. However, in women taking hormone replacement therapy (HRT), the protective effect of exercise seemed to be cancelled out. But increased awareness of the side effects of HRT means that its use is decreasing in a number of countries, and this means that the beneficial effects of activity will most likely grow in the years to come. “Whether or not this will be the case is an interesting question and deserves to be followed up at a later date,” Prof Boniol said.

Physical activity is known to have a protective role in other cancers, as well as in disorders such as cardiovascular disease. Although the mechanisms for its effect are unclear, the results are largely independent of body mass index (BMI), so the effect must be due to more than weight control. And the age at which sporting activity starts also appears to be immaterial; the researchers found no indication that breast cancer risk would decrease only when physical activity started at a young age.

“Adding breast cancer, including its aggressive types, to the list of diseases that can be prevented by physical activity should encourage the development of cities that foster sport by becoming bike and walk-friendly, the creation of new sports facilities, and the promotion of exercise through education campaigns,” said Prof Boniol. “This is a low cost, simple strategy to reduce the risk of a disease that currently has a very high cost, both to healthcare systems and to patients and their families. It is good news both for individuals and for policy makers.”

My Take: Women have a real impetus to increase their physical activity by even modest increments. This review comfirms that improvements in breast health can now be added to the other established health benefits of physical activity. So keep moving! I love for my patients to get a minimum of the equivalent of a brisk walk, 5 times per week. If you can do more, great. But even that small amount of additional activity can add years to your life, while potentially lowering your risk of heart attack, stroke, dementia, and 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.

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 European CanCer Organisation (ECCO). “Regular physical activity reduces breast cancer risk irrespective of age.” ScienceDaily. ScienceDaily, 20 March 2014. <www.sciencedaily.com/releases/2014/03/140320100816.htm>.

Exercise Protects Against Aggressive Breast Cancer in Black Women

imsis530-020

A nearly 20-year observational study involving more than 44,700 black women nationwide found that regular vigorous exercise offers significant protection against development of an aggressive subtype of breast cancer. The findings from the Black Women’s Health Study were presented at the 2013 San Antonio Breast Cancer Symposium, December 10-14, 2013.

The research team, co-led by scientists at Georgetown Lombardi Comprehensive Cancer Center in Washington, DC, and Boston University in Massachusetts, found that black women who engaged in brisk exercise for a lifetime average of 3 or more hours a week had a 47% reduced risk of developing estrogen receptor (ER)-negative breast cancer compared with those exercising an average of 1 hour per week, according to a preliminary analysis. The study included 44,704 women age 30 years or older.

This form of breast cancer, which includes human epidermal growth factor receptor 2 (HER2)-positive and triple-negative tumors, is linked to both higher incidence and mortality in black women, relative to white women. ER-negative tumors do not respond to hormone therapies used to treat tumors that have the estrogen receptor.

“These findings are very encouraging. Knowing that exercise may protect against breast cancers that disproportionately strike black women is of great public health importance,” said Lucile Adams-Campbell, PhD, professor of oncology and associate director of Minority Health & Health Disparities Research at Georgetown Lombardi. We all want to do what we can to reduce our risk of disease and improve our health, and along with other well-known benefits, we now show that exercise can possibly stave off development of potentially lethal breast cancer in black women,” she said.

Exercise, at any level, appeared to have no effect on development of ER-positive breast cancer in these women, the researchers said. They cannot offer a reason why because their study was not designed to answer this question. They also cannot speculate on whether vigorous exercise in white or Asian women would have any effect.

My Take: This study adds to a growing body of literature pointing to a role for exercise in reducing cancer risk. While more appears to be better, many find success startnig with 15o minutes of brisk walking daily (30 minutes, 5 times per week, for example), and build up from there. 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.

Physical Activity Extends Lives of Cancer Survivors

exercise jogging mature older elderly man activity physical

Physical activity significantly extends the lives of male cancer survivors, a new study of 1,021 men has found.

During the period while the men were followed, those who expended more than 12,600 calories per week in physical activity were 48 percent less likely to die than those who burned fewer than 2,100 calories per week. Kathleen Y. Wolin, PhD, of Loyola University Chicago Stritch School of Medicine, is co-author of the study, published in the Journal of Physical Activity & Health, the official journal of the International Society for Physical Activity and Health.

Background: Many cancer survivors are living longer, due to earlier diagnosis and better treatment, and their numbers are increasing rapidly. “Thus physical activity should be actively promoted to such individuals to enhance longevity,” researchers concluded. There has been extensive research showing that among generally healthy, cancer-free populations, physical activity extends longevity. But there has been relatively little such research on physical activity among cancer survivors.

Study Design: Researchers examined data from the Harvard Alumni Health Study, an ongoing study of men who entered Harvard as undergraduates between 1916 and 1950. Researchers looked at 1,021 men (average age 71) who previously had been diagnosed with cancer. In questionnaires conducted in 1988, men reported their physical activities, including walking, stair-climbing and participation in sports and recreational activities. Their physical activities were updated in 1993, and the men were followed until 2008.

Results: Compared with men who expended fewer than 2,100 calories per week in physical activity, men who expended more than 12,600 calories per week were 48 percent less likely to die of any cause during the follow-up period. This finding was adjusted for age, smoking, body mass index, early parental mortality and dietary variables. (By comparison, a 176-pound man who walks briskly for 30 minutes a day, five days a week burns 4,200 calories.)

What You Need to Know: There were similar findings for mortality from cancer and cardiovascular disease: the most physically active cancer survivors were 38 percent less likely to die of cancer and 49 percent less likely to die of cardiovascular disease during the follow-up period. If you are able to do so, aim for a minimum of 30 minutes of the equivalent of a brisk walk at least 5 days per week. If your healthcare provider gives you clearance to do even more, this study suggests that you should do so. 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: Loyola University Health System. “Physical activity significantly extends lives of cancer survivors.” ScienceDaily. ScienceDaily, 23 January 2014. <www.sciencedaily.com/releases/2014/01/140123124652.htm>.

Journal reference: I-Min Lee, Kathleen Y. Wolin, Sarah E. Freeman, Jacob Sattlemair, Howard D. Sesso. Physical Activity and Survival After Cancer Diagnosis in MenJournal of Physical Activity and Health, 2014; 11 (1): 85 DOI: 10.1123/jpah.2011-0257