Recent Smart Bytes™ posts have been sharing latest research on how time we spend in activity and time we spend sitting may impact health both directly and through effects on our weight. Cancer survivors are wondering how this information pertains to them. For a long time we didn’t have much research involving survivors. Today, it’s among the hottest areas of research looking at how cancer survivors can reduce risk of recurrence and improve their overall health outlook.
Here’s today’s bottom line on physical activity and cancer survivors from the latest major reviews that pull research together for the big picture view.
Why the Message is Changing
For a long time, experts were hesitant to say much about physical activity for cancer survivors, because there just wasn’t a lot of data to back them up. It seemed likely that physical activity could be a positive influence, since research has linked regular physical activity to lower cancer risk and so many other health benefits. But creating a more physically active lifestyle is not easy for anyone, let alone someone who may be experiencing cancer-related fatigue, trying to fit in a host of medical appointments, and already summoning considerable emotional energy to stay focused on recovery. Is getting more active worth the effort?
Now an analysis of 45 studies on physical activity and cancer survivors published in the Journal of the National Cancer Institute adds increased strength to the recommendation that physical activity may offer multiple benefits to cancer survivors.
- Breast cancer survivors, the most-studied group, show deaths due to breast cancer decreasing 13 to 51 percent by those who were most active compared to those least active.
- Deaths from all causes were 20 to more than 60 percent lower among the most active. This is important, since with improvements in cancer treatment, heart disease is the most common cause of death for breast cancer survivors.
- Survivors of colorectal cancer, one of our most common cancers in men and women, also show a fairly consistent 40 to 60 percent fewer colon cancer deaths and deaths from all causes among the most active.
- Among other cancer survivors, results about cancer-related deaths are less clear, but limited research suggests overall deaths are lower among those who get most activity.
- Moderate physical activity may lead to healthful changes in insulin and related growth factors that can promote cancer development, and possibly to decreased inflammation. The great news is that some evidence among breast cancer survivors suggests the protective insulin-related changes may be greatest for women most likely to have elevated insulin and benefit most from decreased levels – women who are obese or sedentary.
A few insights on the details from these studies
Hearing results phrased as reduction in risk among the “most active” may sound daunting. Don’t let it: these most active people were not running marathons. The survivors classified as most active were getting moderate activity, such as a brisk walk, three to six hours a week. That’s a big jump if you’re exhausted or not used to making time for activity, but it’s not training for the Olympics. Besides, what we see so far is that some is better than none when it comes to activity.
Studies consistently show that two of the most consistent benefits of physical activity among cancer survivors are decreased fatigue and increased quality of life. If energy is low during treatment, some people find that even very small amounts of light activity are helpful. Some studies find that activity when treatment (or all but hormonal treatment in breast cancer survivors) is completed may bring even greater improvements in energy level. So if you’ve gotten very sedentary and feel out of shape following treatment, supervised exercise with a professional who knows how to gradually work you up to moderate activity may bring many benefits.
The Fine Print
Could the links between exercise and better outcome following cancer treatment simply reflect that people able to be more active are healthier? In other words, is greater activity the result of improved survivorship, not the cause? That may be part of the link seen. However, especially in more recent studies, researchers often try to statistically adjust data for differences in stage and treatment of cancer, so that comparisons reflect people in similar situations. Also, the intervention trials testing impact on metabolic markers such as insulin and inflammation are adding important information.
Cancer survivorship occurs in stages. Decisions about the best time to start physical activity, and its type and intensity, should be made by cancer survivors based on input from their doctors about their individual medical condition. Those who were active before cancer may need to reduce intensity or time during chemo- or radiation therapy. People who have been sedentary and want to get some activity during treatment may need to start even more gradually than usual, possibly with slow, ten-minute walks and very light stretching.
Many survivors become deconditioned during cancer treatment, losing muscle strength and cardiovascular fitness. Some may have lost weight; others may lose muscle but gain body fat, especially men with prostate cancer treated with androgen deprivation therapy. Physical activity that’s the right match can make a difference for many.
Unique concerns of cancer survivors
Consequences of cancer or its treatment can pose unique concerns for cancer survivors:
- Survivors with severe anemia should postpone exercise, other than activities of daily living, until the anemia is improved.
- Other conditions don’t necessarily rule out physical activity, but make certain adaptations or choices advisable on a short-term basis: decreased immune function, radiation therapy, indwelling catheters, nerve damage, balance problems, bone metastases or hormonal treatments that put bone health at risk.
- Lymphedema, a swelling that can occur after lymph node removal or radiation to the underarm area, does not require avoidance of exercise, including strength training. It may even reduce incidence and severity of lymphedema, according to recent research. However, women should discuss with their doctor the potential need for a well-fitting compression garment during exercise.
- People who have received certain treatments that can damage the heart – certain medications or left-sided radiation therapy – may be at risk from adding exercise. Again, another reason that it’s very important to discuss plans for getting more active with your doctor, who knows your personal circumstances.
The most recent review from a combined team of the National Cancer Institute and researchers renowned in this field paints a picture showing that physical activity may be a valuable part of a health-promoting lifestyle for cancer survivors. We need to know more about how people at different stages in their journey as survivors may benefit. The results discussed above relate mainly to the growing population of survivors who are disease-free or who have stable disease following recovery from treatment. As cancer diagnosis and treatment continue improving, we will have more and more survivors in this boat.
The next Smart Bytes™ post will get back to our more typical nutrition discussions. Sign up by RSS feed or email to make sure you don’t miss a thing!
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.
You’ll find American Institute for Cancer Research physical activity guidelines for cancer survivors on the AICR website. AICR also offers a brochure, Surviving Cancer with Physical Activity, which is available for viewing or as up to six copies in print free of charge.
Ballard-Barbash R, et al. Physical Activity, Biomarkers, and Disease Outcomes in Cancer Survivors: A Systematic Review. J Natl Cancer Inst. May 8, 2012. ( epub ahead of print).
Schmitz, KH et al. American College of Sports Medicine Roundtable on Exercise Guidelines for Cancer Survivors. Medicine & Science in Sports & Exercise, July 2010. 42( 7):1409-1426.
Rock, CL et al. American Cancer Nutrition and Physical Activity Guidelines for Cancer Survivors. CA Cancer J Clin, 2012.
Schmitz KH, et al. Weight lifting for women at risk for breast cancer-related lymphedema: a randomized trial. JAMA. 2010 Dec 22;304(24):2699-705.