The Emerging Role of Exercise in Cancer Prevention and Treatment

A Conversation With Susan Gilchrist, MD, MS; Sara Mijwel, PhD; and Kathryn H. Schmitz, PhD, MPH

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The holistic benefits derived from exercise in preventing and ameliorating chronic health conditions such as cardiovascular disease and diabetes are well documented. However, less is known about the salutary effects exercise may have across the cancer setting, especially during treatment.

Originally, researchers looking into this question sought to find out whether there were specific “doses” of exercise that could be tailored to different people with cancer. Since then, the oncology community has placed greater emphasis on understanding the effects and limitations of exercise for patients with cancer and have made significant efforts to integrate and update data-proven exercise regimens into the continuum of cancer care.

A Little Goes a Long Way

Although the multiple benefits of exercise across the spectrum of cancer care are widely acknowledged, the effects of sedentary behavior in the cancer population had not been formally quantified until recently. A study from The University of Texas MD Anderson Cancer Center found that greater inactivity was independently associated with a higher risk of dying of cancer.1 “This is the first study to definitively show a strong association between not moving and cancer death,” lead author Susan Gilchrist, MD, MS, told The ASCO Post.

Susan Gilchrist, MD, MS

Susan Gilchrist, MD, MS

To measure sedentary behavior, 8,002 participants in a National Institutes of Health–sponsored REGARDS project, who did not have a cancer diagnosis at enrollment, wore an accelerometer on their hip during waking hours for 7 consecutive days. The accelerometer data were gathered between 2009 and 2013. MD Anderson researchers found that replacing 30 minutes of sedentary time with physical activity was associated with a 31% lower risk of cancer death for moderate-intensity activity, such as brisk walking, and an 8% lower risk of cancer death for light-intensity activity, such as housework.

“When I meet with my patients, many will cite a number of reasons why they don’t have time to exercise. So, I’ll just ask them to try standing up and move for several minutes every hour or simply take a walk around the house a couple of times. That might not sound like much, but our study confirms that even light exercise or just moving is beneficial for cancer survival,” noted Dr. Gilchrist. “Given our findings, we want to drill deeper into this issue, and our next project will investigate how objectively measured sedentary behavior affects site-specific cancer incidence and whether gender and race play a role.”

Heart Healthy

Dr. Gilchrist, a board-certified cardiologist, joined MD Anderson’s Clinical Cancer Prevention department in 2015. The next year, she opened the Center’s Healthy Heart Program, open to patients with any type of cancer, offering an initial screening and assessment, including a fitness test.

“I actually have a unique role in that I do preventive cardio-oncology. That means I think about ways to prevent cardiotoxicity in patients with cancer who are exposed to agents such as anthracyclines or radiation, which can negatively affect the heart. My main focus is to utilize exercise to promote heart health in patients with cancer and survivors. Also, many of my patients with cancer undergoing chemotherapy have a sense of losing control. Exercise helps them regain their physical and mental fortitude. Being part of the Healthy Heart Program allows them to engage and make shared decisions about their exercise regimen and keep their heart healthy,” noted Dr. Gilchrist.

Although the nascent cardio-oncology specialty is growing, MD Anderson is reportedly the first institution to have a dedicated preventive cardio--oncology program. “One thing a lot of people fail to recognize is that, when you use interventions to modify risks for heart disease, you’re also potentially modifying several cancer--related outcomes that overlap with risk factors, such as excess body weight and sedentary behavior,” said Dr. Gilchrist. She also stressed the need for increasing knowledge within the oncology community regarding the role of exercise interventions for patients with cancer.

Dr. Gilchrist offered the most important takeaway from this study. “The less people sit, the more it protects them against cancer death. I believe our study lays the groundwork for a firmer understanding of how various levels of exercise (even, as I’ve stressed, simply getting up and moving around) can provide benefits in long-term cancer survival.”

A Former Tennis Pro Gives Back

A native of Huntsville, Alabama, Dr. Gilchrist picked up a tennis racket at age 9 and quickly developed into an accomplished player throughout grade school, garnering a scholarship to The University of Texas (UT), Austin, and leading UT to a national championship in 1993. She turned pro, playing in the U.S. Open and French Open against the world’s top competitors. Although her pro career was shortened by injury, Dr. Gilchrist brought tennis into her later career as a cardio-oncologist. Hearing that several patients with cancer longed to play tennis again, Dr. Gilchrist secured court rights at Rice University and has offered clinics to engage patients to be active.

“I’m willing to do whatever it takes to empower people to make changes that protect them from heart disease. If playing tennis with a former professional motivates someone, I’m willing to do it,” said Dr. Gilchrist.

Study Looks at Exercise During Chemotherapy

Although exercise during chemotherapy is suggested to offer certain benefits, a paucity of randomized clinical trials have studied such clinical outcomes. In an effort to fill that gap, researchers in Sweden conducted the OptiTrain Breast Cancer Trial. The study, which focused on women with breast cancer during and after chemotherapy and hormonal therapy, compared the effect of different physical training programs on patients’ physical and mental well-being. Using data from the OptiTrain trial, a group of investigators recently looked at how exercise affects chemotherapy completion and hospitalization rates, as well as blood cell concentrations during chemotherapy.2

A total of 240 women scheduled for chemotherapy were randomly assigned to 16 weeks of resistance and high–intensity interval training, moderate–intensity aerobic and high–intensity interval training, or usual care. Outcomes included chemotherapy completion; hospitalization; and hemoglobin, lymphocyte, thrombocyte, and neutrophil concentrations during chemotherapy.

“This study addressed the clinical outcomes of two exercise programs during chemotherapy for patients with early–stage breast cancer. In contrast to previous studies, we did not find any positive effects of exercise on completing the chemotherapy sessions according to plan,” lead author Sara Mijwel, PhD, told The ASCO Post.

Sara Mijwel, PhD

Sara Mijwel, PhD

Dr. Mijwel continued: “We did however find that exercise in the form of combined resistance training and high–intensity interval training was effective to reduce the frequency of being hospitalized during the chemotherapy period. Both exercise regimens in the study—combined resistance training and high–intensity interval training and aerobic training combined with high–intensity interval training—led to a positive effect on platelet levels.”

Asked for a takeaway message, Dr. Mijwel, a researcher at the Karolinska Institutet in Sweden, said: “This means that performing high-intensity exercise during chemotherapy could have a positive impact for the health of women with breast cancer and could reduce costs related to treatment complications.”

Evidence-Based Guidelines

Multiple international organizations have issued evidence-based exercise guidelines for patients with cancer and cancer survivors, among them the American Cancer Society and ASCO. Yet, despite these efforts, the majority of people with cancer are not engaged in regular physical activity. In 2019, an expert panel convened by the American College of Sports Medicine released its guidance and recommendations on the role of physical activity and exercise in cancer prevention and survivorship.3

In a recent conversation with The ASCO Post, Panel Co-Chair Kathryn H. Schmitz, PhD, MPH, explained how exercise affects survivorship. “Our epidemiology research shows that exercise reduces the risk of cancer recurrence and mortality in breast, colon, and prostate cancer survivors in particular. There may be other cancers in this category of benefit, but we don’t have confirmatory trial data on them yet. To understand how/if exercise reduces the persistent adverse effects of cancer treatments, our roundtable panel did a systematic review of 16 cancer-related health outcomes to see whether prescribing exercise like a medicine, in terms of frequency, type, intensity, and amount of time spent, might have a measurable medicinal effect.”

Kathryn H. Schmitz, PhD, MPH

Kathryn H. Schmitz, PhD, MPH

Dr. Schmitz continued: “We found that there are eight cancer-related health outcomes for which we can draw a fit prescription: cancer-related fatigue, anxiety, depression, quality of life, typical function, sleep, bone health, and lymphedema (for breast cancer). So, we have confirmed that exercise is as efficacious and safe as a medicine to treat these eight treatment-related symptoms.”

Weightlifting and Lymphedema

In the past, clinicians typically advised their patients with lymphedema to rest and avoid physical activity, especially weightlifting. “With lymphedema, you have a damaged body system that produces severe swelling, tenderness, lack of mobility, and pain. It might seem counterintuitive that weightlifting would have any benefit in this setting. However, several well-done trials, including my own 2009 study published in The New England Journal of Medicine,4 showed that, in breast cancer survivors with lymphedema, slowly progressive weightlifting had no significant effect on limb swelling. And, in fact, it resulted in a decreased incidence of exacerbations of lymphedema, reduced symptoms, and increased strength.”

‘Exercise Is a Win-Win’

Despite the data-based evidence showing the benefits of exercise in the cancer setting, the message is not being fully disseminated within the oncology community at large, noted Dr. Schmitz. “Published evidence tells us that only about 20% of patients with cancer are being told by their oncologists to be more physically active. The data are clear that the effects of exercise are as large as a prescribed medical intervention for eight designated symptoms in cancer treatment. At some point, not prescribing exercise for patients with cancer should be considered malpractice.”

“Lack of time is cited as a deterrent to discussing an exercise treatment plan. I recently completed a trial in which we tried something novel to counter the lack-of-time issue. We imbedded an exercise professional into the chemotherapy suite who rounded with the medical oncology team. In that setting, 70% of the patients agreed to an exercise program, following the guidelines. Evidence shows that people with cancer will have better health outcomes than those who do not exercise. Moreover, our new study also demonstrates that if oncologists integrate an exercise specialist into their practice, it may save time and money because patients may experience reduced side effects and be less likely to need emergency care or hospitalization. Exercise is a win-win for patients with cancer and the system as a whole,” said Dr. Schmitz. “The sole focus of my ongoing work is translating the robust evidence-based data that exercise is extremely useful for people living with and beyond cancer into standard clinical practice.”

DISCLOSURE: Dr. Gilchrist has served as a consultant for Outcomes4Me. Dr. Mijwel and Dr. Schmitz reported no conflicts of interest.


1. Gilchrist SC, Howard VJ, Akinyemiju T, et al: Association of sedentary behavior with cancer mortality in middle-aged and older US adults. JAMA Oncol 6:1210-1217, 2020.

2. Mijwel S, Bolam KA, Gerrevall J, et al: Effects of exercise on chemotherapy completion and hospitalization rates: The OptiTrain Breast Cancer Trial. Oncologist 25:23-32, 2020.

3. Campbell KL, Winters-Stone KM, Wiskemann J, et al: Exercise guidelines for cancer survivors: Consensus Statement from International Multidisciplinary Roundtable. Med Sci Sports Exerc 51:2375-2390, 2019.

4. Schmitz KH, Ahmed RL, Troxel A, et al: Weight lifting in women with breast-cancer-related lymphedema. N Engl J Med 361:664-673, 2009.