In a new study from Harvard Medical School, researchers found that exercise training may slow tumor growth and improve outcomes for females with breast cancer—especially those treated with immunotherapy drugs—by stimulating naturally occurring immune mechanisms.
In the study, the team found tumors in mouse models of human breast cancer grew more slowly in a structured aerobic exercise program, and the tumors in exercised mice exhibited an increased anti-tumor immune response.
The team says the most exciting finding was that exercise training brought into tumors immune cells capable of killing cancer cells known as CD8+ T cells and activated them.
With more of these cells, tumors grew more slowly in mice that performed exercise training.
They say humans whose tumors have higher levels of CD8+ T cells tend to have a better prognosis, respond better to treatment, and have a reduced risk of cancer recurrence compared with patients whose tumors have lower levels of the immune cells.
CD8+ T cells are also essential for the success of drugs known as immune checkpoint inhibitors, such as Keytruda (pembrolizumab), Opdivo (nivolumab) and Yervoy (ipilimumab), which have revolutionized therapy for many types of cancer, but have to date had only limited success in breast cancer.
The researchers found that exercise could boost response to immune checkpoint blockade.
They say that daily sessions of a moderate-to-vigorous intensity, continuous aerobic exercise training, lasting 30-45 minutes per session could be prescribed to a patient referred to an exercise oncology program.
The current clinical guidelines focus on general wellness, improved fitness levels and quality of life, but not necessarily on improved cancer treatment, especially immunotherapy, and that this lack of evidence limits its application in clinical practice.
If you care about breast cancer, please read studies about these 7 things may increase breast cancer risk and findings of a new way to block the spread of breast cancer.
For more information about breast cancer prevention and treatment, please see recent studies about breast density: common myths every woman should know and results showing that new method may enhance treatment for breast and pancreatic cancer.
The study is published in Cancer Immunology Research. One author of the study is Dai Fukumura, MD, Ph.D.
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