Research is now quite consistent in showing that cancer survivors benefit from regular physical activity. This has been demonstrated in studies that follow large populations over time and in randomized controlled intervention trials. Now come many questions about who benefits most and who warrants extra precautions in exercise, as well as questions about type, intensity and timing of exercise.
In the first portion of my interview with Lee Jones, PhD, he discussed the current understanding about physical activity for cancer survivors. He discussed why the common cancer-related fatigue should not deter a survivor from aiming for some exercise. Dr. Jones is among researchers at the forefront of intervention trials with cancer survivors, and in this portion of our interview, he shares what he sees research showing about the optimal timing of physical activity following a cancer diagnosis.
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Cancer therapy & “the hit”
Advances in cancer treatments, including chemotherapy, radiation therapy and surgery, are causes for celebration, as survival rates of many cancers are improving. However, Dr. Jones notes, many of these treatments have side effects, including damage to the heart and lungs. As a result, fitness levels decrease, which in turn has a negative effect on quality of life, since people may find themselves unable to do the things they want to do.
Furthermore, as treatment for some cancers, such as breast cancer have become more effective, survivors of these cancers may be more likely to die from heart-related causes than from cancer.
- Dr. Jones notes that people may experience a decline in heart- and lung-related fitness in just 12 weeks of chemotherapy that is comparable to the decline that might normally occur over 10 years of normal aging.
- The decline in fitness resulting from chemotherapy does not automatically resolve when treatment ends. Dr. Jones notes that in one study, even seven years after therapy ended, women were still substantially below the fitness of sedentary women the same age without cancer.
Overall research findings
- In an analysis of six intervention trials of people with early stage cancers, those not assigned to exercise decline in fitness, while those in supervised exercise programs during, and especially following treatment, improve. People varied in how well they responded to exercise, and generally improved in fitness more slowly than do typical people without cancer.
- An analysis of 82 studies, mostly randomized controlled trials, found that fatigue, quality of life and depression improved most in exercise programs following, rather than during cancer treatment.
- Other reviews of combined studies show that quality of life and cancer-related fatigue improve more in supervised, facility-based exercise programs rather than when survivors are given handouts and asked to exercise on their own. And moderate exercise seems more effective than very light exercise.
However, researchers consistently note that exercise goals and plans need to be tailored to the health, treatment effects and needs of each individual cancer survivor.
Balancing benefits & concerns
Besides damage to heart and lung function, some cancer treatments can lead to nerve damage, muscle pain or impaired immune function, each of which may pose challenges to exercise and change recommended approach to activity.
Breast cancer survivors are often afraid that exercising the arm on the same side as their affected breast could lead to the major swelling called lymphedema. According to two respected researchers in oncology exercise, several studies have looked at this issue and concluded that the benefits of appropriate upper body exercise far exceed the risks. These researchers, Kathryn Schmitz, PhD, MPH, and Rebecca Speck, MPH, say,
“Unfortunately, the fear of lymphedema leads many women to adopt lifestyle choices that decondition the arm, which may place the arm at a greater risk than gradually and progressively increasing the strength and endurance of the arm after surgery.”
Looking specifically at breast cancer survivors, Schmitz and Speck do caution that cancer and its treatment can have long-lasting effects that call for extra caution in exercise testing and extra awareness of signs of trouble while exercising. For example, they say that a woman under 50 years old after chemo- or radiation therapy needs the same precautions in exercise testing as a woman over 50 who never had cancer. They conclude that regularly engaging in exercise that improves aerobic, strength, flexibility and balance conditions will probably improve the experience of survivorship, both medically and psychologically.
In our interview, Dr. Jones also emphasized that for all the potential benefits of exercise for cancer survivors, the extra risks associated with cancer treatments make checking with the doctor before any significant change in physical activity especially important for cancer survivors.
Bottom line: Studies so far show exercise providing greater benefits after cancer treatment than during treatment. However, the potential Dr. Jones notes in our interview for survivors to reduce the negative side effects of cancer therapies by getting some exercise during treatment, which is currently not established by research, would be a benefit with great potential, indeed.
LIVESTRONG at the YMCA is a twelve-week, small group program designed for adult cancer survivors. Check the program website to see if the program is available in your community.
You can find an ACSM/ACS Certified Cancer Exercise Trainer, someone who knows how to adapt physical activity to meet specific exercise-related concerns of cancer survivors. Find one in your area through the ACSM ProFinder website: http://certification.acsm.org/pro-finder
Jones LW et al. Effect of exercise training on peak oxygen consumption in patients with cancer: a meta-analysis. Oncologist. 2011. 16(1):112-20.
Speck RM et al. An update of controlled physical activity trials in cancer survivors: a systematic review and meta-analysis. Journal of Cancer Survivorship, 2010. 4(2):87-100.
Ferrer RA et al. Exercise interventions for cancer survivors: a meta-analysis of quality of life outcomes. Ann Behav Med. 2011 Feb;41(1):32-47.
Brown JC et al. Efficacy of exercise interventions in modulating cancer-related fatigue among adult cancer survivors: a meta-analysis. Cancer Epidemiol Biomarkers Prev. 2011. 20(1):123-33.
Schmitz KH and Speck RM. Risks and benefits of physical activity among breast cancer survivors who have completed treatment. Women’s Health, 2010. 6(2):221-238.