Effects of Exercise on Cytokine Profiles in Breast Cancer Survivors: A Systematic Review.

backgroundThe role of exercise in modulating the immune system and cytokines has garnered increasing attention, particularly in the context of breast cancer survivorship. Breast cancer and its treatments often lead to immunosuppression, which can heighten the risk of infections and recurrence. Emerging evidence suggests that various forms of exercise, including aerobic and resistance exercise, can positively influence cytokine profiles in breast cancer patients. However, the specific effects and underlying mechanisms remain underexplored.

objectiveWe aimed to conduct a systematic review of the studies focused on the effects of exercise on cytokine profiles of breast cancer survivors.

methodsThe databases of Cochrane Library, PubMed, Science Direct, Scopus, SPORTDiscus, and Web of Science were searched until 31 December 2024, following PRISMA guidelines. Randomized controlled trials were included if they compared breast cancer survivors participating in a structured exercise program with a non-exercise control group and measured cytokine variables both before and after the intervention. The quality of the included studies was rated with the PEDro scale.

resultsEleven studies with 481 individuals undergoing exercise interventions were included in the analysis and compared to 240 individuals as controls. Participants in these studies ranged in age from early 40s to late 50s. These studies examined the effects of various exercise interventions, including resistance exercise (n = 2), aerobic exercise (n = 2), concurrent aerobic + resistance exercise (n = 5), tai chi (n = 1), and yoga (n = 1). The training period ranged from 8 to 52 weeks, with most studies lasting 12-15 weeks. The average frequency of training was three sessions per week with a mean session duration of 55 min. The quality of the studies showed a mean PEDro score of 6.5 ± 0.9 points (range 5-8 points). Both aerobic and resistance training alone or in combination impacted several immune indices, including decreases in serum concentrations of interleukin-15 (IL-15), macrophage migration inhibitory factor (MIF), TNF-α expression in NK and NKT cells (NKTNF-α, and NKTTNF-α), and lower IL-10/TNF-α ratio. Other less habitual exercise interventions such as tai chi and yoga also induced positive effects on immune indices.

conclusionBreast cancer survivors enrolled in several forms of exercise training showed improved cytokine parameters compared with counterparts who did not perform exercise. The benefits of exercise training on cytokine profiles of breast cancer survivors were evident with both aerobic and resistance training, whether performed separately or in combination, and with other training regimens such as tai chi and yoga.