Brain cancer patients who are able to exercise live significantly longer than sedentary patients, scientists at the Duke Cancer Institute report.
The finding, published online Monday in the Journal of Clinical Oncology, adds to recent research that exercise improves how cancer patients feel during and after treatments, and may also extend their lives.
"This provides some initial evidence that we need to look at the effects of exercise interventions, not only to ease symptoms but also to impact progression and survival," said Lee W. Jones, PhD, associate professor in the Duke Cancer Institute and senior author of the study.
Although the study was not designed to test whether regular exercise actually causes longer survival among brain cancer patients, it established a strong correlation that could give doctors and patients a more accurate prognosis of long-term survival.
The study enrolled 243 patients at the Preston Robert Tisch Brain Tumor Center at Duke with advanced recurrent gliomas, lethal brain malignancies that typically result in a median life expectancy of less than six months.
The patients who reported participating in regular, brisk exercise ¬- the equivalent of an energetic walk five days a week for 30 minutes - had significantly prolonged survival, living a median 21.84 months vs. 13.03 months for the most sedentary patients.
The self-reported exercise behavior offered an important additional means of predicting survival among the glioma patients beyond other measures traditionally used for prognosis, including a six-minute walk test.
Jones said the walk test is a good way to gauge the functional capacity of people with heart failure or other cardiac or pulmonary disorders, but it may not be informative for brain cancer patients who frequently suffer dizzy spells and other neurological problems that hamper walking.
Jose Cortes, a Duke patient who has battled inoperable anaplastic astrocytoma since 2009, has been an avid proponent of the power of exercise during his treatment.
"I exercised regularly prior to my illness and I wanted to stay as active as possible," Cortes said. "But it was impossible for me to do things that I could do easily before. My first goals in physical therapy were to put on my shoes without tipping over and keep my equilibrium while walking and talking or walking and turning my head."
As he met and surpassed his early goals, he began walking for 30 minutes a day and last year joined a Zumba fitness-dance class at his local YMCA.
"I wanted to be able to exercise because it makes me feel alive again," Cortes said. He cautioned that exercise is no cure – his cancer has responded well to chemotherapy – but he said being active helps both physically and mentally.
"Exercise is a very good way to overcome the side effects of your disease," he said. "You can feel more positive about your life even if you are in a terminal state. The most important thing is to just do it at your own pace and do your best."
The Duke study demonstrates that if doctors know about their patients' exercise regimens, they will have a better way to assess long-term outcomes. Jones said an accurate prognosis is important to determine the overall health of patients, potential tolerance for certain types of treatment, and eligibility for clinical trials.
Jones said a major goal of his research is to discover why exercise may lead to improvements in survival following a cancer diagnosis.
"Discovering these mechanisms could provide new insights into cancer progression," Lee said. "It could also lead to novel studies where exercise is combined with certain cancer therapies to see if both interventions together are more effective at inhibiting cancer recurrence or progression, not just minimizing the adverse side effects of the cancer therapies."