Exercise generally helps the nation's 12 million cancer survivors, but researchers are still working toward being able to prove, with scientific certainty, that prescriptions for daily yoga or 20 minutes of walking will likely extend a patient's survival.
Understanding specifically how exercise benefits subpopulations of cancer patients is among the big topics at the American Society of Clinical Oncology (ASCO) 2012 annual meeting in Chicago, June 1-5, 2012. Several scientists from the James P. Wilmot Cancer Center at the University of Rochester Medical Center are part of the ASCO discussion, including Lisa K. Sprod, Ph.D., a junior faculty member who is being recognized with an ASCO Merit Award.
"In 15 years we've gone from being afraid to recommend exercise to people with cancer, to having enough data that shows, by and large, it is safe and effective, particularly for relief of treatment side effects," said Karen Mustian, Ph.D., M.P.H., assistant professor of Radiation Oncology at URMC and an exercise psychologist specializing in cancer. "But when a patient walks in the door, he or she wants to know how to tailor exercise to their own situation. Should I bike, walk, or lift weights? Is there anything I should avoid? Can certain exercises lower my fatigue? And the scientific community has not settled into a place where we've developed explicit exercise prescriptions, or can effectively narrow the choices for patients."
Several URMC suggest that knowing how to develop and apply specific exercise programs (dose and timing to achieve a certain outcome) is a realistic goal.
Mustian and Sprod investigated physical activity among older people, a group they describe as often overlooked and underestimated in terms of their ability to live with cancer. On June 2 at ASCO they will present two studies in a session titled, Staying Bold While Old:
Mustian conducted a phase II clinical trial to discover whether six weeks of a home-based exercise plan (walking and resistance bands) improved cancer-related fatigue and strength in 58 men with prostate cancer who were treated with radiation and androgen deprivation therapy.
The mean age of the group was 67. The men had a wide range of fitness levels, from frailty to golfers who were fit and active. A control group that did no exercise was also established.
Researchers measured cardiopulmonary function (through a gold-standard test called Vo2-peak) and muscular strength, and found that all exercisers improved while the control group declined in performance. The most significant information, Mustian said, was that everyone who exercised regularly achieved some added benefit even the fittest participants.
A larger study is planned to explore whether the physiological effects of exercise are responsible for improvements, or if a psychological component is also present, such as the personal attention one often gains from an exercise program, or the camaraderie of being with friends at a gym.
Sprod investigated the appropriate amount, type, and intensity of exercise in cancer survivors older than 65, who are also experiencing the natural functional declines associated with aging. The double hit, she said, is an understudied issue.
After analyzing a national sample of 14,887 people, Sprod established that older cancer survivors engage in less physical activity even routine activity such as stooping, lifting, and walking than people without a history of cancer. This may lead to less independence, a higher risk of the cancer coming back, and reduced survival.
The study raises new questions, such as whether the treatment contributes to less activity, or whether patients and physicians are worried about the safety of becoming physically active during and after cancer treatment, or a combination of the two factors, Sprod said.
In another exercise-related study, Luke J. Peppone, Ph.D., a research assistant professor, investigated the effects of a yoga program on women with breast cancer who were taking aromatase inhibitors, medications that deplete estrogen and often cause severe menopause-like symptoms. A frequent complaint is joint pain and muscle aches, sometimes making it difficult for women to get out of bed or grip a fork and knife.
Peppone said a high percentage of breast cancer survivors discontinue aromatase inhibitor therapy because of side effects, putting them at greater risk for cancer recurrence. His study measured the self-reported quality of life and physical discomfort among 95 women taking aromatase inhibitors and 72 women who were not taking the drug.
Each group took part in a four-week gentle yoga program. The women taking aromatase inhibitors reported a significant reduction in pain, muscle aches, and total physical discomfort, Peppone said. The study will serve as a pilot to launch a larger study of exercise to relieve musculoskeletal pain.
His research, as well as Sprod's study, also was selected for presentation at the Multinational Association of Supportive Care in Cancer meeting in June in New York.
Finally, a controlled study of yoga therapy in middle-aged, mostly female cancer survivors showed that a four-week, customized gentle yoga plan significantly reduced perceived difficulty with memory. Michelle C. Janelsins, Ph.D., research assistant professor at Wilmot, randomized patients to one of two groups: standard follow-up care after receiving adjuvant cancer treatment, and standard care plus a program that consisted of breathing exercises, gentle Hatha and Restorative yoga postures, and meditation.
The yoga group had significantly reduced memory difficulty compared to the standard care control group.
Improved memory also partially contributed to improved fatigue and improved quality of life, Janelsins noted.
In some ways, Mustian said, the exercise-and-cancer dilemma harkens to the days when it was not known what types of chemotherapy and how much should be given to cancer patients. Through rigorous scientific inquiry, physicians were able to refine the way they prescribe and administer chemo and Mustian believes the same refinement is possible with exercise.
"I think we do an incredible disservice to people who have just been diagnosed with cancer when we say, 'Just do it!' Mustian added. "Sometimes we see 72-year-olds who are more fit than 55-year-olds, and so it is best to look at functional capacity, and then to be as specific as possible when it comes to personalizing exercise for people with cancer. Otherwise we are sending mixed messages."
Sprod, a research assistant professor, will receive the ASCO Pain and Symptom Management Research Merit Award; she is one of 4 young investigators whose ASCO research presentations were selected for a high impact. All exercise studies were funded through a variety of private and government sources, including the National Cancer Institute.
|Contact: Leslie Orr|
University of Rochester Medical Center