Effects of Yoga on Inflammatory Markers in Cancer: A Systematic Review of Randomized Controlled Trials

Abstract Introduction: Chronic inflammation plays a crucial role in cancer progression and contributes to tumour initiation, growth, and metastasis. Yoga, a mind-body practice, has the potential to modulate inflammatory pathways, reduce stress, and improve the overall well-being of patients with cancer. This systematic review aimed to evaluate the impact of yoga on key inflammatory markers and cortisol levels in cancer patients based on evidence from randomised controlled trials. Methods: A systematic search was conducted across databases, including PubMed, Cochrane Library, Web of Science, and Scopus, encompassing studies published between January 2000 and August 2024. Studies were deemed eligible if they involved cancer patients, utilised yoga as an intervention, and measured inflammatory markers as outcomes. Data on the study characteristics, population, intervention details, and outcomes were extracted. The risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Results: Fourteen randomized controlled trials (RCTs) involving various types of cancer, including breast, prostate, hematologic, and gastrointestinal cancers, were included. These findings demonstrate that yoga significantly reduced pro-inflammatory markers, particularly tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), while increasing the anti-inflammatory cytokine interleukin-10 (IL-10). Cortisol levels have been consistently lowered across multiple studies. However, the effects on C-reactive protein (CRP) levels are heterogeneous, with some studies reporting no significant changes. Despite the inherent challenges in blinding participants and personnel in yoga interventions, the overall risk of bias across studies was evaluated as low to moderate. Conclusion: Yoga appears to be an efficacious complementary intervention for reducing inflammation and improving immune responses in cancer patients. The consistent reduction in pro-inflammatory markers and stress-related hormones underscores the potential benefits of yoga in cancer care. Future research should focus on standardising yoga interventions, exploring their long-term effects, and expanding the scope of the study population to corroborate these findings.