Women with breast cancer who exercise regularly before treatment and in the years following may live longer and are less likely to experience recurrence, suggests a recent study. The study also suggests inactive patients who start being active after treatment – even a modest amount – can also have survival benefits.
The analysis, published in the Journal of the National Cancer Institute, adds to a strong and mounting body of evidence showing the health benefits of activity for cancer patients and survivors.
AICR recommends that cancer survivors, when able, follow the same physical activity recommendation and other guidelines outlined in AICR’s Cancer Prevention Recommendations.
Last year, the American College of Sports Medicine (ACSM) confirmed previous findings that exercise is generally safe for cancer survivors and that every survivor should aim to “avoid inactivity.”
Benefits of modest and moderate physical activity
This latest study was embedded in a clinical trial that was testing the effects of a chemotherapy regimen among patients diagnosed with high-risk breast cancer. The research included 1,340 patients enrolled in the trial along with the Diet, Exercise, Lifestyle and Cancer Prognosis (DELCaP) Study, a prospective study of lifestyle and prognosis led by Christine Ambrosone, PhD.
When patients enrolled in the study, they filled out a questionnaire about their exercise and other lifestyle habits. They completed the questionnaire again while undergoing chemotherapy, one year after their study treatment and then two years after treatment.
The study used the government’s Physical Activity Guidelines to categorize activity levels. Patients were classified as meeting the guidelines if they were recreationally active for at least 150 minutes per week at a moderate intensity or its equivalent.
After analysis, researchers found that the patients who met the minimum activity guidelines both before diagnosis and after treatment had more than a 50 percent reduced risk of recurrence and mortality compared to those not meeting the guidelines at either point. Patients who met the guidelines before and two years after treatment had the most beneficial outcomes with a 55 percent lower risk of their cancer recurring and a 68 percent lower risk of dying from any cause during the course of the study.
There was also positive news for the women who increased their activity after treatment. Patients not doing 150 minutes of moderate activity a week prior to diagnosis, but who did two years after treatment, experienced lower risk of recurrence and mortality compared to patients not meeting the guidelines at either time.
When analyzed by the amount of activity, benefits were seen among patients who were consistently active, but for less time than the guidelines recommend. Compared to those who were inactive, patients regularly active less than the 150 minutes per week had similar survival benefits as those meeting the exercise guidelines. Being highly active – more than 300 minutes per week – linked to even greater survival.
“Aiming for as little as two and half hours a week of exercise – the minimum under federal guidelines – can have a big impact for women with high-risk breast cancer,” said Rikki Cannioto, PhD, EdD, of the Department of Cancer Prevention and Control at Roswell Park Comprehensive Cancer Center and lead author of the study. The association between those who exercised even relatively low amounts and cancer survival was striking. “Our research shows that some physical activity is far better, in terms of cancer survival, than no activity at all.”
There are several study limitations, including the use of self-reported data and the possibility of recall error. And while researchers adjusted for age, tumor characteristics and other factors, these and other unaccounted for factors may have influenced the results.
Numerous health benefits for exercising breast cancer survivors
This JNCI study supports earlier research by Cannioto that concluded survivors who were active one to two times a week survived longer when compared to inactive survivors. Three to four activity bouts a week was even better. That study included patients diagnosed with a wide range of early to late-stage cancer types.
“Similarly, lower volumes of exercise were associated with a significant survival advantage,” said Cannioto. “That really makes sense because we know physical activity is associated with lower all cause mortality.”
Large reviews of the research have concluded that physical activity offers numerous health benefits to survivors and that some is better than none. Much of this research focuses on the more common cancers, such as breast and colorectal cancer; evidence is increasing among other sites.
The 2018 U.S. Physical Activity Guidelines Advisory Committee concluded there was moderate evidence that increasing amounts of physical activity among women diagnosed with breast cancer links to lower risks of breast cancer-specific mortality and all-cause mortality. The review found similar findings among colorectal cancer survivors and evidence showed that high amounts of physical activity lowered the risk of prostate cancer-specific mortality among prostate cancer survivors.
To lower risk of dying from cardiovascular disease and any cause, some activity is better than none, the report found. The ACSM review found enough evidence to conclude that certain amounts of aerobic, aerobic combined with resistance training and/or resistance training could improve common cancer-related health outcomes, including anxiety, depressive symptoms, fatigue, physical functioning and health-related quality of life. Cancer patients are advised to work with their health care team for exercise guidance.
Despite the evidence, about a third of adult US cancer survivors report doing no recreational physical activity.
Exercise and cancer prevention
AICR research has found that regular physical activity lowers the risk of developing breast cancer, along with colorectal and endometrial cancers. Clear and consistent research shows that regular physical activity, along with a healthy diet and weight, lowers the risk of developing many of the most common cancers. These healthy habits can also prevent other chronic conditions, such as diabetes and obesity, that are associated with cancer risk.
Regular physical activity helps to support the immune system, reduces chronic inflammation and helps the body maintain healthy levels of hormones like insulin and estrogen. Abnormal levels of these hormones can play a role in many cancers.
Physical activity can also help with weight control. Aside from not smoking, maintaining a healthy weight is one of the most important steps people can take to lower cancer risk.
Cancer survivors wanting to make healthier habits can join AICR’s free iTHRIVE program, an educational tool that offers an integrative approach to health.
The JNCI research was supported by funders that include the Breast Cancer Research Foundation and Roswell Park Comprehensive Cancer Center and National Cancer Institute grant.