Cancer and exercise

Cancer is a common disease, and according to the World Health Organization, more than 18 million worldwide were diagnosed with cancer in 2018, a number that is estimated to increase further in the coming decades. Advances in detection and treatment have improved cancer-specific and overall survival following diagnosis, but many cancers are still difficult to treat. Unfortunately, however, cancer treatment is often associated with major side-effects. This chapter first discusses how cancer genes become mutated during cell division or by mutagens such as tobacco smoke and how they then drive cancer hallmarks (cancer-specific cell behaviours) to give rise to a malignant cancer. Next, this chapter discusses how exercise can influence tumour biology. Generally, exercise alters the composition of the blood by changing the concentrations of metabolites, proteins, hormones and cells. The exercise-conditioned blood then also perfuses a cancer whose cells can respond, e.g. by changing their proliferation, metabolism or gene expression if they express receptors or other targets for exercise-modulated molecules or cells. Finally, the chapter discusses the role of exercise in managing common side-effects of treatment, including mechanisms for accelerated muscle loss seen following several treatment modalities.