Effects of Exercise on Immune Function in Patients with Cancer: a Systematic Review

Background The role of exercise therapy in the rehabilitation of cancer patients and survivors is becoming increasingly important as it is thought to modulate immunity and inflammation. More knowledge about the effects of exercise on immune function in these patients is needed. Our aim is to systematically review changes in immune parameters after acute and chronic exercise in cancer patients. Results Of the 3586 retrieved articles, 21 met the inclusion criteria, and were included in this systematic review. The systematic search yielded 18 articles in adults, and three in children. Six were of low methodological quality, mainly due to lack of blinding of the assessor and high drop-out rates. The effect of chronic exercise on immune function was examined in 18 studies, while two studies evaluated the effects of acute exercise, and one study combined acute and chronic exercise. Following exercise, increases were seen in Natural Killer cytotoxic activity, as well as lymphocyte proliferation and the number of granulocytes. The number of leukocytes, lymphocytes, Natural Killer cells, T lymphocytes, C-reactive protein, and pro- and anti-inflammatory mediators remained stable. Limitations Of the 21 included studies:, only three were conducted in the pediatric population, and many studies have included small and heterogeneous samples. Due to the large variety in exercise training protocols and immune parameters, no meta-analysis has been performed. Conclusions Various immune parameters improved after exercise; however, knowledge of the effects of exercise on immune function in cancer patients is still limited. Additional research is needed to gain insight into the mechanism underlying the effects of exercise on immune function in different populations, and to link these immune parameters to clinical outcomes.