Breast cancer is the most common cancer worldwideTrusted Source and a leading cause of death among women.
Whereas five-year survival rates for the condition exceed 90%Trusted Source in high-income countries, the scenario is different in low and middle-income countries — India and South Africa, they stand at 66% and 40%.
Studies showTrusted Source that physical activity is associated with a decrease in breast cancer risk. Other research suggests that physical activity reducesTrusted Source breast cancer mortality.
Further research into how physical activity impacts mortality among breast cancer survivors could improve post-cancer care.
Recently, researchers investigated the effects of exercise levels on risk of mortality among breast cancer survivors.
“The study found that even moderate physical activity was associated with a 60% lower risk of death among breast cancer survivors, and results were similar for breast cancer survivors who were more active,” Dr. Reina Haque, senior cancer epidemiologist in the Kaiser Permanente Southern California Department of Research & Evaluation, senior author of the study, told Medical News Today.
The study was published in Jama Network OpenTrusted Source.
15 minutes of activity a day
For the study, the researchers included 315 women with a median age of 71 years old. Among them, 20.9% were African American or Black, 8.99% Asian or Pacific Islander, 1.3% Hispanic, and 68.9% non-Hispanic White.
All participants were members of a healthcare plan in California and had been diagnosed with early-stage breast cancer between 1996 and 2012.
They were interviewed between 2013 and 2015, and filled in questionnaires detailing their leisure time, physical activity, and levels of fatigue.
Participants were categorized into three groups for physical activity: active, moderately active, and insufficiently active—characterized by light or less frequent physical activity for less than an average of 15 minutes daily.
Participants were followed for a median of 7.8 years. Over the study period, 14.3% of the cohort, or 45 participants, died. Five of these participants died from breast cancer.
After analyzing the data, the researchers found that mortality rates were 12.9 per 1,000 people among active participants, 13.4 per 1,000 among moderately active participants, and 32.9 per 1,000 among insufficiently active participants.
Mortality risk was 60% lower for those who were moderately active and 58% lower for ‘active’ when compared to their insufficiently active counterparts.
“Our study shows that breast cancer survivors who exercise at moderate levels, such as walking every day for more than 15 minutes, may experience the same survival benefits as those who do more strenuous exercise.”
— Dr. Reina Haque
How physical activity reduces mortality risk
When asked how physical activity may reduce mortality risk among breast cancer survivors, Dr. Haque explained:
“Cardiovascular disease is one of the leading causes of death in breast cancer survivors, and more physical activity has been shown to be correlated with longer survival. Exercise has positive effects on the body, such as loweringTrusted Source blood pressure, reducing inflammation, modulatingTrusted Source insulin, and loweringTrusted Source obesity.”
“These positive health effects may also apply to survival after a breast cancer diagnosis. Breast cancer survivors who exercised regularly had better health status overall that contributed to longer life,” she added.
Brenda Nettles, assistant professor at Johns Hopkins School of Nursing, not involved in the study, also told MNT: “Physical activity is also associated with improved emotional well-being, which is often challenged by the stressors of cancer treatment and the uncertainty associated with cancer survivorship.”
The researchers concluded that their findings have implications for counseling patients with breast cancer.
“Even moderate levels of exercise appear to be vitally important for extending life,” noted Dr. Haque.
Nettles agreed that survivorship care plans could benefit from including physical activity.
“Survivorship care plans should include recommendations to promote physical, emotional, and spiritual well-being. Cancer survivors are often in search of supportive resources to guide them as they work to establish a new normal after cancer treatment,” she said.
“Incorporating regular physical activity is one way cancer survivors can be empowered to play an active role making lifestyle changes that reduce mortality risks and enhance their quality of life after cancer treatment.”
— Dr. Reina Haque
The researchers noted some limitations to their findings. They were unable to include information on participants’ diets, which they noted may correlate with exercise.
“It is also important to have a more objective approach for evaluating the patient’s level of physical activity. In the study, patients self-reported how many times, on average, they engaged in strenuous, moderate, or mild/light exercise each week,” Nettles added.
“A more detailed account of the duration, intensity, and calories burned would provide a clearer evaluation of the potential benefits for patients that engage in varying degrees of physical activity. Dietary logs that include caloric intake could then be compared to the calories burned during physical activity to evaluate how changes in weight may also impact patient mortality over time,” she concluded.