Exercise Might Enhance the Effectiveness of Cancer Drug, Study finds

Researchers at the Universities of Birmingham and Bath have found that a bout of exercise increased the number of anti-cancer immune cells-called natural killer cells-and that these cells were around twice as effective at killing cancer cells in ‘ex vivo’ tests carried out on blood samples from patients.

The study, published in the journal Brain Behavior and Immunity, showed that the number of cancer cells present in blood samples transiently increased immediately after exercise – making them more susceptible to attack by natural killer cells and the antibody therapy.

Previous research has shown that during an individual bout of moderate to vigorous intensity aerobic exercise in healthy humans, immune cell frequency in peripheral blood increases profoundly.

Regular exercise may increase the body's immune response against cancer by increasing the number of anti-cancer immune cells, specifically natural killer (NK) cells. These specialized immune cells play a crucial role in identifying and eliminating cancerous cells within the body.

Additionally, exercise has been found to improve the overall function of the immune system, creating a more hostile environment for tumor growth and metastasis.

In the study, researchers worked with 20 individuals aged between 45 and 82 who had been diagnosed with chronic lymphocytic leukemia but had not yet undergone treatment. These participants engaged in a 30-minute session of moderate-to-vigorous intensity cycling.

Blood samples were collected before and immediately after the exercise session, with a third sample taken an hour later. The researchers then assessed the number of natural killer cells present in the blood samples at each time point under 'ex vivo' conditions.

Additionally, they evaluated the ability of these natural killer cells to target and kill cancer cells, both with and without the presence of Rituximab.

They found the number of natural killer cells increased by 254% after exercise and that in the blood samples taken after exercise, there were 67% more cancer cells compared to blood before exercise.

Further, the team isolated natural killer cells and put them in close contact with cancer cells for 2 hours ‘ex vivo’ with and without the antibody therapy Rituximab and discovered that when Rituximab was also present in the blood sample, natural killer cells were just over twice as effective in killing the cancer cells in the samples collected immediately after exercise compared to before.

“Cancer cells often try to ‘hide’ in the body but it seems that exercise works to move them out into the bloodstream, where they are vulnerable to the antibody therapy and the killing capabilities of natural killer cells. This study underscores the beneficial role of exercise in cancer treatment, suggesting its utility before, during, and after therapy. Physical activity has been shown to enhance coping mechanisms during treatment, support recovery, and boost mental well-being among cancer patients. Additionally, the results could also have the potential for patients who have finished their treatment for leukaemia and are in a monitoring phase in case cancer cells re-appear,” said the study authors.

Reference: Harrison D. Collier-Bain, et al.; A single bout of vigorous intensity exercise enhances the efficacy of rituximab against human chronic lymphocytic leukaemia B-cells ex vivo; Brain, Behavior, and Immunity; 2024; https://doi.org/10.1016/j.bbi.2024.03.023.