By Jyothirmai Gubili, MS, Donna Wilson, RN, MSN, RRT, and Jun J Mao, MD MSCE
Until the 1980s, the value of exercise was unrecognized in the oncology setting. It was widely believed that patients with cancer undergoing cytotoxic treatments needed to rest and avoid exercise. But a 1989 study conducted by Winningham and Mac Vicar, both oncology nurses at the Ohio State University, dispelled this notion. The trial involved 45 women receiving adjuvant chemotherapy for operable breast cancer and showed that a 10-week interval-based, aerobic exercise was not only safe but also significantly improved body composition, aerobic capacity, and patient-reported nausea.
Current Evidence
Since the pivotal study, considerable data have emerged that indicate a positive association among exercise, cancer prevention, and healthier survivorship, encompassing the cancer continuum. A review of 126 high-quality epidemiological studies showed that compliance with physical activity recommendations of the World Health Organization was associated with a 7% decrease in overall risk of cancer. The correlation was strongest for female breast cancer and colorectal cancer.
And a Cochrane systematic review of 56 trials that included 4,800 patients with cancer reported that moderate-intensity or vigorous exercise during active treatment produced greater improvements in physical functioning, anxiety, fatigue, sleep disturbances, and health-related quality of life.
Physical activity also confers benefit in patients with advanced cancer. In a systematic review that included 16 studies with more than 500 participants with advanced malignancy, aerobic exercise, rehabilitation regimens, or group exercise improved physical fitness and function and increased feelings of vitality.
The effects of exercise have also been explored in cancer survivors. A large meta-analysis of 22 prospective studies involving 123,574 breast cancer survivors revealed that postdiagnosis, greater engagement in physical activity decreased all-cause and breast cancer-specific mortality and breast cancer recurrence.
Although the precise mechanisms underlying the beneficial effects of exercise are not fully known, preclinical data suggest that it regulates immune and inflammatory functions that may positively impact cancer outcomes. In rodent models, exertion resulted in release of myokines, which increase insulin sensitivity and have pro-apoptotic effects and inhibit development of chemically-induced aberrant crypt foci in the colon with implications for colon cancer. Additionally, a translational study involving patients with prostate cancer reported improved fitness and body composition and a reduction in prostate-specific antigen doubling time following a two-year home-based endurance training program.
What This Means for Oncology Nurses
A large body of evidence indicates that exercise has profound effects in patients with cancer and survivors. Increased physical activity is associated with increased overall survival, especially in those with breast and colorectal cancers, and with reduced cancer-specific mortality. Current guidelines recommend prolonged aerobic exercise of low to moderate intensity carried out at least 150 minutes per week, in divided sessions, as well as two to three resistance training sessions each week.
Oncology nurses are uniquely positioned to encourage patients to stay physically active during and beyond cancer treatment, paying attention to the toxicities associated with cancer treatments, including neuropathies related to certain chemotherapy regimens, increased risk for fractures and cardiovascular events because of hormonal therapies, musculoskeletal morbidities, and cardiotoxicity. For patients at risk, medical assessments and exercise testing may be needed before prescribing physical activity. Consult with fitness specialists who have experience working with patients or survivors and understand how surgical procedure, chemotherapy, and radiation treatments can affect patients.