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!

In Prostate Cancer, Regular Walking May Boost Quality of Life

What You Need to Know: Engaging in a regular walking regimen can improve well-being for men with prostate cancer.

The Study: In the new study, a team led by Siobhan Phillips, Ph.D., of the Northwestern University Feinberg School of Medicine in Chicago, tracked outcomes for 51,529 early-stage prostate cancer survivors in the United States, who completed a survey about their quality of life.

  • Many of the men reported having urinary and bowel problems, erectile dysfunction, and other sexual function problems, as well as weight gain, fatigue, and depression.
  • The men also provided information about the average amount of time per week they spent walking, jogging, running, cycling, swimming, and playing sports.

Results: Three hours of “casual” walking per week boosted the men’s health-related quality of life by reducing fatigue, depression, and weight issues. Walking at a faster pace for 90 minutes a week provided similar benefits, the team found.

My Take: You don’t have to engage in high-impact, vigorous activities to improve your quality of life after a prostate cancer diagnosis. Just keep 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.

Reference: Phillips, Siobhan M., et al. “Physical activity, sedentary behavior, and health-related quality of life in prostate cancer survivors in the health professionals follow-up study.” Journal of Cancer Survivorship. DOI: 10.1007/s11764-015-0426-2. April 16, 2015.

Lethal Metastatic Prostate Cancer May Spread from Other Sites

What You Need to Know: Multiple targeted therapies may be needed to combat metastatic prostate cancer because metastasis may be spread from multiple tumor clones according to a new study. “{The findings} are eye-opening,” said study investigator William Isaacs, PhD, who is a professor of urology at the Johns Hopkins Brady Urological Institute and a member of The Johns Hopkins Kimmel Cancer Center in Baltimore, MD. “It emphasizes the aspects that these cancers are evolving at an almost continual rate.”

The Study: Using whole-genome sequencing, Dr. Isaacs and colleagues characterized multiple metastases arising from prostate tumors in 10 men with metastatic castration-resistant prostate cancer (mCRPC). The team analyzed the subclonal architecture of prostate cancer cells and found that:

  •  Metastasis-to-metastasis spread was found to be common through de novo monoclonal seeding of daughter metastases.
  • Researchers found a transfer of multiple tumor clones between metastatic sites in 5 of the 10 patients.

The researchers believe that a new view of mCRPC is now emerging that tumor cells share a common heritage but subclones develop metastatic potential. The data suggest clonal diversification may occur in part as a necessity to bypass androgen deprivation therapy (ADT) and subsequently drive distinct subclones onto a convergent path of therapeutic resistance.

My Take: Whole-genome sequencing on the samples showed that even though a single cell begins the metastatic process, the disease becomes very heterogeneous as it spreads throughout the body over time. These new findings support the notion that treatments for metastatic cancers should include a combination of therapies that target a variety of genetic pathways.  The idea that metastatic tumors can seed and establish other metastatic tumors in patients is different from traditional theories that the primary tumor is solely responsible for disseminating cancer cells with metastatic potential. To me, this work is beautiful, pointing to a new way to see and manage metastatic cancer. I’m Dr. Michael Hunter.

Reference: Gundem G, Van Loo P, Kremeyer B, et al. The evolutionary history of lethal metastatic prostate cancer. Nature. 2015;520(7547):353-357.

Prostate Cancer Family History Linked to Breast Cancer Risk

What You Need to Know: Family history is a significant risk factor for breast cancer, especially in women who have first-degree relatives with the disease. That risk might be even higher if there is a first-degree relative with prostate cancer, a new study suggests.

  • In women with a family history of prostate cancer, there was a 14% increase in the relative risk of developing breast cancer. However, in women with a family history of both breast and prostate cancer, the relative risk increased to 78%.
  • In addition, the risks associated with a family history of both breast and prostate cancer was higher in black women than in white women.

“While this study is limited to largely postmenopausal women, one might expect to see a similar or stronger risk in younger women,” said first author Jennifer Beebe-Dimmer, MPH, PhD, from the Karmanos Cancer Institute and Wayne State University School of Medicine in Detroit. “We tend to see a stronger family history of breast cancer among women diagnosed at younger ages, and the same may be true for a family history of prostate cancer,” Dr Beebe-Dimmer told Medscape Medical News. We believe that physicians may want to consider family history of prostate cancer in addition to breast cancer before making recommendations about screening,” she added.

Dr Beebe-Dimmer pointed out that there is some evidence that men might have a higher risk for prostate cancer if they have first-degree relatives with breast cancer.

“We and others have shown the opposite association, particularly when female relatives are diagnosed with early-onset disease,” she said. “It has been suggested that a relatively small proportion of the prostate cancer cases diagnosed in families with breast and/or ovarian cancer are related to BRCA1/2, suggesting that there may be other genes and/or shared environmental exposures that explain the clustering.”

Multiple Relatives Increases Risk

  • The study included  78,171 women who participated in the Women’s Health Initiative Observational Study from 1993 to 1998. The women were followed for a median of 132 months from the date of enrollment, and there was a median of 60 months between enrollment and the diagnosis of breast cancer. There were 3506 cases of incident breast cancer diagnosed in the cohort up to August 31, 2009.
  • Participants with breast cancer were more likely than those without to be white non-Hispanic and college educated, and to have a history of hormone use and benign breast disease. They were also more likely to have undergone mammography screening within 2 years of the baseline examination.
  • Median age at the time of breast cancer diagnosis was 69 years (range, 50 – 90 years).
  • A positive family history of breast cancer was reported by 11,608 women in the cohort, and women with breast cancer were more likely than those without to report a family history of the disease (20.5% vs 14.6%).
  • Having a single family member with breast cancer was associated with an increase in risk of approximately 40%, after adjustment for cofounders (hazard ratio [HR], 1.42; 95% CI, 1.30 – 1.55). Having multiple family members with breast cancer increased that risk (adjusted HR [aHR], 1.66; 95% confidence interval [CI], 1.32 – 1.88).
  • Women with breast cancer were also more likely than those without to report that at least one first-degree relative had been diagnosed with prostate cancer (11.6% vs 10.1%). This family history was associated with a significant, albeit modest, increase in breast cancer risk after adjustment for confounders such as a family history of breast cancer (aHR, 1.14; 95% CI, 1.02 – 1.26).
  • The risk was highest for those with a family history of both breast and prostate cancer (aHR, 1.78; 95% CI, 1.45 – 2.19).
  • When the data were stratified by race, the risk was highest in black women who had “multiple affected first-degree family members” (aHR, 2.85; 95% CI, 1.33 – 2.08). A family history of prostate cancer was modestly predictive in both white and black women, but only reached statistical significance in white women. Although black women with a family history of both diseases appeared to be at greater risk of developing breast cancer (aHR, 2.34; 95% CI, 1.09 – 5.02), “the risk estimates were not significantly different as evidenced by the overlapping CIs,” note Dr Beebe-Dimmer and colleagues.

Reference: Cancer. Published online March 9, 2015. Abstract    

Electronic Noses Sniff Out Cancer

Earlier this year, I speculated that electronic “noses” would someday be able to detect cancer. Now, I can report that we are getting closer (although trained dogs still seem better at the task!).

Background: It’s the second most common cancer for men worldwide, but prostate cancer remains difficult to diagnose, with standard blood tests criticized for delivering a high rate of false positives. But in a study presented in May this year, trained detection dogs were able to identify prostate cancer from a few sniffs of a urine sample with a staggering 98% accuracy, with few false positives. Although the study is by no means conclusive, it joins a growing body of research suggesting dogs could be able to smell out cancers.

However, there are numerous practical problems in using dogs to detect cancers in a medical setting (not least training, consistency and identifying exactly which chemicals the dogs are detecting), which is why scientists are seeking to harness the potential detection ability of man’s best friend through the development of an “electronic nose” capable of making a diagnosis.

Finnish researchers are using a device that conducts molecular analysis of the atmosphere in the “headspace” above urine samples, and tests it for the volatile organic compounds associated with prostate cancer. In a study published earlier this year, the method had a detection rate of 78%, and a specificity (the probability of the test being negative when cancer is absent) of 67%.

Researchers continue to refine the method, such as through removing impurities for cleaner sample analysis, but he believes the principle is reliable and can be applied to many other cancers.

“We have found there are over 30 molecule compounds in a tumor that are very smelly and easily sniffed. Eventually this can be used as a test for every cancer in the Western world,” he added.

Around the world, similar approaches are being applied to offer simple diagnosis for the world’s greatest killers. In 2011, the Gates Foundation announced funding for a battery-operated electronic nose prototype in India that functions as a breathalyzer test for tuberculosis.

The “NaNose” is being developed by the Israeli Technion Institute, claiming 90% accuracy in detecting lung cancer from a breath test, and providing enough information to distinguish between subtypes of the disease.

My Take: Dogs are still better, but I am confident that they will help to recognize diseases based on body odors. A dog recognizes thousands of odors at a time, so machines have a bit of learning to do to catch up. 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: http://www.cnn.com/2014/07/16/tech/innovation/electronic-noses-sniff-out-disease/index.html?hpt=hp_bn5

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.

PSA Blood Test Saves Lives

What You Need to Know: Prostate-specific antigen (PSA) screening is controversial, but a new study shows PSA is associated with a lasting reduction in your risk of dying from prostate cancer, with an increased effect at 13 years compared with nine or 11 years.

The Study: European Randomised study of Screening for Prostate Cancer (ERSPC) is a multi center, randomized trial assessmentt of PSA testing in eight European countries for men ages 50 to 72. Data truncated at 13 years.

Results: At 13 years, the absolute risk reduction of death from prostate cancer was 0.11 per 1,000 person-years or 1.28 per 1,000 men randomized.

My Take: In this update, the ERSPC confirms a meaningful reduction in prostate cancer mortality attributable to the PSA blood test, with an even greater effect at 13 years compared to 9 and 11 years. While the use of screening PSA is controversial, this well-done study points to a PSA-linked reduction in the risk of prostate-related death. 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 Lancet, Early Online Publication, 7 August 2014.