Moderate exercise is a radiosensitiser - it improves radiotherapy results - and reduces side-effects because it increases oxygen in the bloodstream, damaging the hypoxic pocket of cancer tumours and weakening them.
Radiotherapy for prostate cancer improved by exercise
Solid tumours contain pockets of hypoxia in them; and those areas show a resistance to radiotherapy. Exercise can reduce hypoxia in tumours by improving oxygen levels. 2020 research with prostate cancer has shown that it also helps oxygenate tumours by increasing blood vessel supply (vascularisation) and it even seems to increase levels of Natural Killer cells in and around the tumour (1). This finding from the Exercise Medicine Research Institute in Western Australia is important. Currently in the UK NICE approves only surgery or radiotherapy for early prostate cancer treatment.
Some 7 years previous, an ongoing programme of the use of exercise in the USA showed and explained many of these features.
Kansas State research on exercise and radiotherapy
Brad Behnke, Associate Professor of Exercise Physiology in the Department of Kinesiology at Kansas State University (2) has shown that moderate exercise on a regular basis enhances tumour oxygenation. His team have also compared the effects of exercise or no exercise with mice given protate cancer. They found that exercise improved radiotherapy effectiveness. It's an ongoing project.
Other research shows that moderate exercise can help cancer patients counteract some of the side-effects of treatments, such as low blood count, fatigue, cachexia and lost muscle mass, and this has led to many researchers labeling this as "aerobic exercise therapy" for patients with cancer,
"There really aren't any negative side effects of moderate-intensity exercise," said Behnke. "Exercise is often prescribed to improve the side-effects of cancer and treatment, but what exercise is doing within the tumour itself is likely beneficial as well."
Behnke has combined his expertise in integrative physiology with cancer research, linking with Kansas State University's Johnson Cancer Research Center.
Behnke is using prostate cancer tumor models to find ways to enhance oxygen delivery to tumors.
When a tumour is hypoxic, (has low oxygen), it is often very aggressive, Because oxygen is a "radiosensitizer," it helps radiotherapy destroy cancer cells.
Low-oxygen tumors often are resistant to traditional cancer therapies, such as radiation therapy, and interventions, such as concentrated oxygen breathing (Hyperbaric Oxygen, for example), are used to get more oxygen to the tumor before treatment.
"If we manipulate all the systems in the body the lungs, the heart and the blood vessels with exercise, we can take advantage of the dysfunctional vasculature in the tumour and enhance blood flow to the tumor," says Behnke. "The tumour becomes the path of least resistance for the elevated cardiac output of exercise, which results in a substantial increase in tumor oxygenation during and after exercise."
But the key is moderate exercise, says Behnke. Too little exercise may have no effect, but too much exercise may have a negative effect and may shut down blood flow to the tumor region or impair the immune system.
At Kansas State University, Behnke is collaborating with Mary Lynn Higginbotham, assistant professor of clinical sciences. The American Cancer Society has provided the grant, and the study, "Modulation of tumor oxygenation to enhance radiotherapy," also involves the University of Florida researchers in tumor microenvironment biology.
Behnke and collaborators have published their 'exercise and cancer' research in the Journal of the National Cancer Institute.
The National Cancer Institute at the National Institutes of Health recommends exercise for cancer patients and cancer survivors.
Go to: Hyperbaric Oxygen improves Chemotherapy and radiotherapy
References
1. Nature - Prostate Cancer 2020 July 6th - Oliver Schumacher et al; Exercise modulation of Tumour Perfusion and hypoxia to improve radiotherapy response in prostate cancer.
2. Dr Bradley Behnke - Kansas State University