The University of Pennsylvania has reported that exercise may help to boost the cancer fighting effect of chemotherapy.
Please do not read this as “exercise cures cancer” (no doubt at least one tabloid newspaper will interpret this research in this way). The research has so far only been carried out on mice with melanoma (skin cancer). The research found that when exercise and chemo was combined tumors shrink more than if only chemo if given.
Joseph Libonati was lead researchers and author, the research paper was published in the American Journal of Physiology. Joseph Libonati is associate professor in the School of Nursing at University of Pennsylvania.
Exercise and cancer
Exercise has actually been prescribed to cancer patients for many years since doctors recognized that it provides both physical and psychological benefits that can improve quality of life during treatment. However, it was not known if it had any real benefit on killing cancer cells. When cancer is diagnosed late there is not an opportunity to do some exercise before chemo; often treatment will have to commence almost immediately to have a chance of being successful.
Prof. Joseph Libonati decided to test the hypothesis that exercise could protect patients from the side effects of the cancer drug doxorubicin, which can often cause cardiac damage. Doxorubicin has been known to damage heart cells and this is thought to pose a risk long-term heart health. Because cancer is the immediate concern, the risks of the drug are acceptable; without the drug patients are unlikely to survive long enough to develop age related health problems.
Previous studies had indicated that people who exercised before receiving chemotherapy were able to provide their hearts with some protection from the toxic damage caused by doxorubicin. Nobody had tested to see if exercise during chemo treatment could have a similar effect.
The study took fours groups of mice, each group suffering from melanoma on their necks. Two of the groups received doxorubicin and the other two groups had no drug (given a placebo). One of each group exercised by walking for 45 minutes a day, while the other groups did no exercise at all. The experiment was designed to see if exercise could reduce damage to the heart when chemo was given.
After two weeks the researchers examined their hearts using echocardiogram (ultrasound scan) and tissue analysis.
As expected, mice that were given the drug showed signs of heart damage, with noticeable reduction in the heart’s function, size and increased fibrosis. The mice that exercised suffered the same damage, i.e. exercise did not help protect the heart at all.
However, the researchers made a very surprising discovery. Prof. Libonati explained: “We looked, and the exercise didn’t do anything to the heart — it didn’t worsen it, it didn’t help it. But the tumor data — I find them actually amazing.”
The amazing effect of exercise on cancer
The mice that had received chemotherapy and exercised had much smaller tumors than those that only received chemo.
This initial study appears to show that when exercise helps to boost the positive effect of chemotherapy. The researchers do not know why and further research is needed to investigate this result.
The researchers believe that the positive effect could simply be because exercise increases blood flow to the tumor and this may help to flood the cancer cells with the drug. In sedentary patients much of the drug may never reach the cells that are being targeted.
Smaller dosages and less side effect
If this turns out to be true, that exercising during chemo can help to reduce cancer faster, it may mean that doctors will be able to prescribe smaller doses of the drug. This will mean that there will be a reduced risk of cardiac damage. So in a way, exercise will actually help to protect the heart – by allowing less doxorubicin to be administered for the same effect.
Of course, chemotherapy is a very aggressive treatment and patients will often not want to exercise during treatment. However, if they can be encouraged to do some supervised exercise there is a possibility that it might help with their treatment.
“Exercise Boosts Tumor-fighting Ability of Chemotherapy, Penn Team Finds” Penn News, The University of Pennsylvania.