Fatigue is such a common—and ongoing—problem among cancer survivors, last spring, ASCO published a clinical practice guideline1 to address screening, assessment, and treatment approaches for the management of fatigue after patients have completed treatment. Among the strategies included in the guideline to help mitigate the problem is the initiation of consistent moderate-level physical activity—defined as 150 minutes of moderate physical aerobic exercise per week and two to three strength-training sessions per week—following cancer treatment.
Jennifer A. Ligibel, MD, a coauthor of the clinical practice guideline and Assistant Professor in the Department of Medicine at Harvard Medical School and Senior Physician in the Women’s Cancer Program at Dana-Farber Cancer Institute, is researching the impact of exercise on fatigue as well as the role exercise may play in preventing cancer or cancer recurrence, especially in breast, prostate, and colon cancers. She reviewed the results from several studies investigating exercise interventions to combat fatigue and pain in cancer survivors during ASCO’s Annual Meeting in June2 and expects to present new data from her current studies on exercise and its affect on cancer during next year’s Annual Meeting. Dr. Ligibel is also among the scientists investigating the relationship of physical activity, energetics (the study of energy under transformation), and nutrition on cancer risk and recurrence in the National Cancer Institute (NCI)-funded Transdisciplinary Research on Energetics and Cancer (TREC) Initiative.
The ASCO Post talked with Dr. Ligibel about what the research is showing on the benefits of physical activity in relieving fatigue after cancer treatment and the role it may play in reducing cancer risk and recurrence.
Common Problem
Why is fatigue such a common and long-lasting problem for cancer survivors?
No one knows the definitive answer to that question. The cause of fatigue is multifactorial. The problem is seen across the spectrum of the cancer experience, from people with early diagnosis who have completed therapy all the way to people with more advanced disease and undergoing therapy.
We think that a number of different factors influence the development of fatigue, including treatment, comorbidities, and psychological factors. The biologic basis of fatigue is also not understood, but recent research focuses on the role of inflammation in the etiology of fatigue. Other projects look at genetic predisposition to fatigue and provide early clues that may explain why one person develops fatigue while another person with the same cancer treated with the same therapy does not.
Clinical Practice Guideline
Please talk about the recommendations in ASCO’s Screening, Assessment, and Management of Fatigue in Adult Survivors of Cancer Clinical Practice Guideline Adaptation you coauthored. How are patients evaluated for fatigue, and what are some strategies for management?
In clinical practice, we recommend that fatigue be assessed as part of the review of systems. If a patient complains about fatigue, we recommend that further questions focus on when fatigue developed, how long it has been present, and how the symptom limits the patient’s ability to carry out responsibilities and engage in activities that the patient typically enjoys.
The ASCO guideline also recommends that other causes of fatigue be ruled out. These recommendations are similar to other fatigue guidelines that have been developed, including the pan-Canadian guideline3 and the National Comprehensive Cancer Network (NCCN) guidelines on fatigue and survivorship.4,5 The guideline does not recommend performing laboratory evaluations or radiologic imaging unless there is a reason to think that patients may have some other condition that is contributing to their level of fatigue.
Specialist Referral
At what point should patients be evaluated by a palliative care specialist?
Referral to a palliative care specialist more commonly occurs when a patient has advanced-stage disease. In this setting, early referral to a palliative care specialist has been shown to have significant benefits in terms of fatigue and other endpoints.
For patients with early-stage disease, the role of palliative care in combating fatigue has not been fully defined, but it is an interesting question.
Exercise and Survival
Please talk about the research showing that exercise can prolong survival and reduce the risk of cancer recurrence in breast cancer and colon cancer survivors.
Observational studies show that individuals who participate in regular exercise after a cancer diagnosis are at lower risk of recurrence and mortality compared to cancer survivors who do not exercise at all. Most of this evidence so far is in survivors of breast, colon, and prostate cancers, but data are being collected in other cancers as well. We do not know if exercise is the cause of better survival, but these studies showing a link between exercise and better survival are fairly consistent.
Levels of Activity
How much exercise is necessary to reap these benefits?
Although it can be hard to make a firm determination of this from the types of studies that have been conducted so far, reports suggest that cancer survivors who engaged in at least 3 to 5 hours of moderate intensity aerobic exercise, such as brisk walking, had better cancer outcomes compared to people who did not exercise at all.
These levels of activity are similar to the Surgeon General’s recommendation for physical activity in the general population, which is about 150 minutes of moderate-intensity activity or 75 minutes of vigorous activity a week.
Other Symptoms
What other symptoms from cancer or its treatment may be relieved with exercise?
Exercise has been shown to improve overall quality of life and fitness. Studies suggest that exercise reduces problems like joint pain associated with the use of breast cancer drugs, for example. There are also studies looking at the impact of physical activity on hot flashes. There are several symptoms associated with cancer or its treatment that have been shown to be improved by physical activity.
Role of Diet
What role does diet play in cancer risk and recurrence?
The relationship between diet and cancer risk/cancer outcomes has been looked at in thousands of studies, but the results are hard to concisely summarize because they show a variety of associations. In colon cancer there is a relationship between foods like red meat and disease onset. In breast cancer the studies are a bit more mixed. A fair amount of data suggests that higher-fat diets may be associated with an increased risk of mortality in women with early breast cancer. The problem is there is also a very strong relationship between weight and breast cancer prognosis, and it is very difficult to disentangle diet and weight in these observational studies.
There have also been large observational studies assessing the relationship between weight and both cancer risk and cancer outcomes and, like physical activity, there are strong relationships between weight and the risk of developing and dying from cancer, especially breast cancer and prostate cancer. ■
Disclosure: Dr. Ligibel reported no potential conflicts of interest.
References
1. Bower JE, Bak K, Berger A, et al: Screening, assessment, and management of fatigue in adult survivors of cancer: An American Society of Clinical Oncology practice guideline adaptation. J Clin Oncol 32:1840-1850, 2014.
2. Ligibel JA: Exercise interventions and more: Combating fatigue, aches, and pains in cancer survivors. 2014 ASCO Annual Meeting. Poster Discussion Session. Presented June 2, 2014.
3. Howell D, Keller-Olaman S, Oliver TK, et al: A pan-Canadian practice guideline and algorithm: Screening, assessment and supportive care of adults with cancer-related fatigue. Curr Oncol 20:e233-e246, 2013.
4. National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Cancer-related fatigue (version 1.2013). Available at www.nccn.org. Accessed December 3, 2014.
5. National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Survivorship (version 1.2013). Available at www.nccn.org. Accessed December 3, 2014.
