New Research Regarding Exercise, Depression Among Cancer Survivors

January 17, 2010

If you are not directly involved with it, the world of medical research can easily seem overly complicated and unnecessarily complex. The truth is this: research does get complicated at times; often many research projects address similar (if not exactly the same) questions. But researchers do recognize this, and ever-so-often, researchers will take a time-out to look at all the research on a specific topic. Sometimes researchers will do this in a more formal way, and they will publish their work as a systematic review and/or meta-analysis. Systematic reviews and meta-analyses are research projects in which the researchers examine all the research on a given topic, and then they summarize what was found.

For example, researchers might ask: Does taking drug X reduce a person's risk of getting disease Y? Then they will look at all the studies that ask this question, and with some fancy math, they will average all the results they find to produce one amalgamated result.

Just a few days ago, the Journal of Cancer Survivorship published a systemic review that examined the effect of physical activity on post-treatment cancer survivors. Essentially, the researchers said, “Everyone is saying that exercise is good for cancer survivors, and that looks to be true, but lets see what it (exercise) really does for cancer survivors!”

The systematic review looked at many articles, and the conclusions are as follows. Post-treatment, targeted physical activity does often increase upper and lower body strength. Additionally, physical activity helps some survivors’ improve their fatigue, but results improving fatigue are far from universal. Also, moderate improvements are seen in post-treatment breast cancer survivors who have experienced lyphadema (lymph node pain and swelling after surgery). When the researchers looked at post-treatment exercise and its effect on improving overall activity level, aerobic fitness, functional quality of life, anxiety, and self-esteem, the results were less clear. With a doubt, for some survivors, exercise improves some or all of these categories, but there are many other survivors who do not experience dramatic improvements due to exercise alone.

Does this mean that exercise should be abandoned if it's not working to solve a survivor’s specific concerns? No. Absolutely not. No. Absolutely absolutely not! The researchers who conducted the systematic review also found that with “few exceptions” exercise was tolerated well by survivors. So the danger of exercising (especially under the direction of a professional) is minimal (make sure you check with your physician before you start any exercise plan!).

For the survivors for whom exercise does not work fantastically, it is most likely the wrong choice to stop exercising (and conclude that it didn’t work). Most likely, the solution those survivors seek INCLUDES exercise, yet exercise alone is not enough. Moreover, often survivors have more than one long-term effect that plagues them. A targeted exercise program may be more effective in alleviating one group of symptoms as compared to another.

Bottom line, this systematic review suggests that the effects of exercise range from very positive to slightly positive and the risk of bad effects is less-than-minimal. So post-treatment exercise for cancer survivors promises some level of benefit with very little risk in exchange. This type of risk/reward ratio is rare in cancer, so it should be grasped when available. You can read more about the study here.

Also, exercise and depression among cancer survivors was the topic of a recently published study. The study population was breast cancer survivors from the very large Shanghai Breast Cancer Survivors' Study. According to this research team, it seems that exercise, in general, does reduce the risk of major depression among cancer survivors (at least breast cancer survivors). However, the story is a bit more complicated than that. The study suggests that the best results in the effort to reduce the risk of depression are achieved when one increases one’s exercise level from whatever point is current. For example, if you are currently a moderate exerciser, and you receive a cancer diagnosis, increasing to an above-moderate level of exercise would seem to reduce your risk of major depressive disorder more effectively than simply remaining at a steady moderate level. However, the bottom line is that when exercise is compared to not exercise or when more exercise is compared to less, exercise or more exercise is always preferable with respect to reducing risk of depression.

What if your treatment or disease makes it impossible for you to exercise during treatment or even after? Are you just out-of-luck? Are you doomed to face major depressive disorder? No! The study also suggests that not exercising does not increase your risk for depression.

This could all be a bit confusing, so think of it like this: a cancer survivor’s risk of depression is like a glass of water. Exercising is like drinking the water; it reduces the risk (the amount of water). But NOT exercising is like not drinking the water. You are not increasing the amount of water in the glass by not drinking; you are not reducing it either. You can read more about the study here.

The take home message from all of this is that exercise, on the whole is good for cancer survivors, and it can help survivors cope with the physical and psychological effects of cancer and treatment.

As always, you can leave a comment here or reach me via email with any questions or concerns.

Christian McEvoy, MPH

Director of Survivorship Information

christian@ctchallenge.org