Living Longer and Living Better

Exercise provides multiple benefits to cancer survivors.

Evidence Builds for Link Between Exercise and Cancer Survival

Though no two people experience cancer in exactly the same way, there are common themes that arise during conversations with cancer survivors. For many the shock of the diagnosis and the challenges of treatment and survivorship provide an opportunity to reassess priorities and to make new life choices. And among the many choices that can improve health and well-being during and after cancer treatment, regular physical activity is emerging as one of the most important.

It makes sense that being physically active would have health benefits for cancer survivors; at a minimum, exercise should reduce the risk of other chronic conditions such as diabetes and heart disease that pose a threat to all of us regardless of our cancer history. Until recently, however, relatively few exercise studies had explored the relationship between exercise and cancer survival.

This began to change in 2005. A study of nearly 3,000 women with Stage I to Stage III breast cancer reported that post-diagnosis physical activity significantly reduced the risk of death from breast cancer.[1] Estimated 10-year survival was 92 percent among women who did the equivalent of three or more hours of walking per week, compared with 86 percent among women who were the least active. Women who did the equivalent of three to five hours of walking per week appeared to derive the greatest survival benefit; increasing activity beyond this point did not appear to provide additional benefits.

The idea that physical activity may improve cancer survival was further supported by two studies of colorectal cancer patients. The first study involved 573 women with Stage I to Stage III colorectal cancer.[2] The second study involved 832 women and men with Stage III colon cancer.[3] In both studies individuals who were more physically active had better survival than sedentary individuals. A difference between the results of these studies and the 2005 breast cancer study, however, is that a higher level of physical activity the equivalent of six or more hours of walking per week appeared to be necessary to achieve a benefit. The reasons for this difference are still unclear, but it’s possible that different cancers have different exercise thresholds.[4]

An important point to notice about each of these studies is that they focused on physical activity that occurred after the cancer diagnosis. And in two of the three studies, post-diagnosis physical activity improved survival regardless of the level of prediagnosis physical activity (one of the studies did not have information about prediagnosis physical activity). This means that even if you were inactive before your cancer diagnosis, it’s not too late to start an exercise program. And if you were active before, these studies should provide additional motivation to stay active.

Although these results are exciting, the link between physical activity and cancer survival is not yet considered conclusive. The studies described above are all observational. In an observational study, the researchers do not assign study participants to a particular treatment group; they simply observe what happens to study subjects with particular characteristics or behaviors. Although well-conducted observational studies can provide very useful information, they tend to be less definitive than randomized clinical trials. Until the necessary clinical trials are conducted, however, the best available evidence suggests that physical activity may provide survival benefits to cancer survivors.

Exercise and Quality of Life

It’s not only the duration of life that matters; quality of life is another important concern for cancer survivors. Even after treatment ends, survivors may face such issues as fatigue, depression, anxiety, and concerns about body image and sexuality. Exercise may help you manage several of these short- and long-term side effects of cancer and cancer treatment.

A recent review of cancer-related fatigue one of the most common and debilitating side effects experienced by cancer patients noted that a growing body of evidence supports the use of exercise to help manage fatigue.[5] Exercise may help manage fatigue even among patients undergoing very intensive treatment. A study among hospitalized patients receiving high-dose chemotherapy and stem cell transplantation, for example, reported that patients who used a cycling machine while lying in bed experienced no increase in fatigue over the course of hospitalization. In contrast, patients who did not engage in physical activity during hospitalization experienced a significant increase in fatigue.[6] Because certain groups of patients may need to take precautions when engaging in an exercise program (see sidebar), it’s important that you talk to your doctor about what’s safe for you.

If you are adapting to physical changes following cancer treatment, exercise may also improve your body image and help you maintain or regain your sense of sexuality. A study of body esteem and mood among women who had completed treatment for breast cancer found that women who were physically active were more likely than sedentary women to report that they felt sexually attractive. The active women also reported less depression, confusion, and fatigue.[7]Higher quality of life, greater interest in sex, and better body image have also been reported among physically active bladder cancer survivors.[8]

While these studies suggest that exercise offers a range of benefits to cancer survivors, the nature of the benefits may vary by whether or not a woman is still receiving cancer therapy. A recent study of aerobic or resistance exercise among women receiving adjuvant chemotherapy for breast cancer found that exercise improved self-esteem, physical fitness, body composition, and among women in the resistance exercise group chemotherapy completion rates; exercise did not, however, significantly improve overall quality of life.[9] Improved quality of life was reported in a study of breast cancer patients assigned to a yoga program but only in the subset of women who were not currently receiving chemotherapy.[10]

If your doctor has said that exercise is appropriate for you, these two studies should not discourage you from exercising during cancer treatment. Some important benefits including greater fitness were reported among women who exercised during cancer treatment; these benefits prompted the authors of one of the studies to state: “Cancer care professionals should consider recommending either (aerobic exercise training) or (resistance exercise training) to breast cancer patients receiving chemotherapy.”[9] The most notable improvements in overall quality of life, however, may come later.

Boost the Benefits with a Healthy Diet

The combination of regular physical activity and a healthy diet is likely to provide more health benefits than either behavior alone. In addition to possible cancer benefits, a lifestyle that includes both a healthy diet and regular physical activity is likely to reduce your risk of other common health problems such as heart disease and diabetes. A healthy diet and regular physical activity can also help you fight the weight gain that affects many cancer survivors.

A healthy diet is one that is rich in fruits, vegetables, and whole grains and that allows you to maintain a healthy body weight. In addition, for the purposes of cancer prevention, the American Cancer Society recommends limiting intake of red meat and alcohol.[11]

Benefits of combining physical activity with a healthy diet were reported by a study of nearly 1,500 women who had been treated for early-stage breast cancer.12 Women who engaged in regular physical activity (the equivalent of 30 minutes of walking six days per week) and who also ate five or more servings of fruits and vegetables a day had the best survival. Estimated 10-year survival was 93 percent among women who engaged in both healthy behaviors compared with 86 to 87 percent among women who engaged in one or neither of the healthy behaviors.

Another important result from this study was that physical activity and a healthy diet provided benefits regardless of body weight. The combination of these behaviors improved survival in both obese and nonobese women. Unfortunately, only 16 percent of obese women and 30 percent of nonobese women reported both regular physical activity and high fruit and vegetable intake. Clearly, there’s room for improvement, and women of all body sizes stand to benefit.

Getting Started

Talk with your doctor before starting an exercise program. To choose the program that’s right for you, you and your doctor will consider your age; previous exercise experience; cancer type, stage, and type of treatment; and other medical conditions.

If your doctor decides that it’s appropriate for you, you may benefit from following exercise guidelines such as those provided by the American Cancer Society.[11] Developed for the general population (and not specifically for cancer survivors), the guidelines recommend that adults engage in at least 30 minutes of moderate-to-vigorous physical activity five or more days per week. A longer duration of exercise (45 to 60 minutes) may provide additional benefits.

Moderate-intensity activity includes brisk walking and cycling on level terrain. Vigorous activity includes cycling or walking up hills and jogging. For a more-complete list of moderate and vigorous activities, visit the physical activity Web site of the Centers for Disease Control and Prevention at http://www.cdc.gov/nccdphp/dnpa/physical/measuring/index.htm.

Do What You Can

Life can be overwhelming even without the added strain of a cancer diagnosis. Don’t get down on yourself if there are days when you just can’t make it out the door for a workout. And if you’re getting out there sometimes but not as much as you’d like remind yourself that something is better than nothing; every step counts.

References:


[1] Holmes MD, Chen WY, Feskanich D, Kroenke CH, Colditz GA. Physical activity and survival after breast cancer diagnosis. Journal of the American Medical Association. 2005;293(20):2479-86.
[2] Meyerhardt JA, Giovannucci EL, Holmes MD, et al. Physical activity and survival after colorectal cancer diagnosis. Journal of Clinical Oncology. 2006;24(22):3527-34.
[3] Meyerhardt JA, Heseltine D, Niedzwiecki D, et al. Impact of physical activity on cancer recurrence and survival in patients with Stage III colon cancer: Findings from CALGB 89803. Journal of Clinical Oncology. 2006;24(22):3535-41.
[4] Demark-Wahnefried W. Cancer survival: Time to get moving? Data accumulate suggesting a link between physical activity and cancer survival. Journal of Clinical Oncology. 2006;24(22):3517-18.
[5] Mustian KM, Morrow GR, Carroll JK, Figueroa-Moseley CD, Jean-Pierre P, Williams GC. Integrative nonpharmacologic behavioral interventions for the management of cancer-related fatigue. The Oncologist. 2007;12(Suppl 1):52-67.
[6] Dimeo FC, Stieglitz RD, Novelli-Fischer U, Fetscher S, Keul J. Effects of physical activity on the fatigue and psychologic status of cancer patients during chemotherapy. Cancer. 1999:85(10):2273-77.
[7] Pinto BM, Trunzo JJ. Body esteem and mood among sedentary and active breast cancer survivors. Mayo Clinic Proceedings. 2004;79(2):181-86.
[8] Karvinen KH, Courneya KS, North S, Venner P. Associations between exercise and quality of life in bladder cancer survivors: A population-based study. Cancer Epidemiology, Biomarkers, and Prevention. 2007;16(5):984-90.
[9] Courneya KS, Segal RJ, Mackey JR, et al. Effects of aerobic and resistance exercise in breast cancer patients receiving adjuvant chemotherapy: A multicenter randomized controlled trial. Journal of Clinical Oncology (early online publication). September 4, 2007.
[10] Moadel AB, Shah C, Wylie-Rosett J, et al. Randomized controlled trial of yoga among a multiethnic sample of breast cancer patients: Effects on quality of life. Journal of Clinical Oncology (early online publication). September 4, 2007.
[11] Doyle C, Kushi LH, Byers T, et al. Nutrition and physical activity during and after cancer treatment: An American Cancer Society Guide for informed choices. CA: A Cancer Journal for Clinicians. 2006;56(6):323-53.
12. Pierce JP, Stefanick ML, Flatt SW, et al. Greater survival after breast cancer in physically active women with high vegetable-fruit intake regardless of obesity. Journal of Clinical Oncology. 2007;25(17):2345-51.

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