Effect of Yoga Intervention on Inflammatory Biomarkers among Women with Breast Cancer – A Systematic Review

BACKGROUND: Inflammatory markers play a substantial role in the prognosis of breast cancer (BC). Studies have been conducted, evaluating the effect of yoga intervention (YI) on inflammatory biomarkers among BC cases. This systematic review consolidates the outcome of YI in the cancer microenvironment. OBJECTIVE: The objective of the study was to evaluate the effect of YI in the cancer microenvironment among BC women. MATERIALS AND METHODS: This review was conducted from May 2021 to December 2021. The inclusion criteria were experimental studies on adult BC cases with isolated YI. Studies conducted among paediatrics, case reports and case series were excluded from the study. Medline (PubMed), Medline (Ovid), Web of Science (WOS), Scopus, CINAHL and Cochrane Central databases were searched. The data were restricted from January 2000 to December 2021 with studies published in English. ‘The Cochrane risk of bias assessment tool’ was mobilised to evaluate the quality of the included studies. RESULTS: A total of nine studies met the inclusion criteria and comprised a sample size of 905 BC cases with a mean age of 50.26±8.27 years. Three studies evaluated tumour necrosis factor-alpha (TNF-α) and INTERLEUKIN (IL)-6, where two studies on TNF-α and one on IL-6 favoured the YI group. A study investigated soluble TNF receptor II (TNF-RII) and another on IL-1beta (IL-1β) has shown improved levels post-YI. A downward trend of cortisol levels was noted in four out of five studies. Two studies that examined the C-reactive protein and a study on IL-8 did not show any difference between the YI and the control groups. CONCLUSION: This review’s findings showed the downregulation of cortisol, markers of inflammation; TNF-α, IL-6, TNF-RII and IL-1β immediately to post-YI. Heterogeneities in terms of YIs, number of days of practice, duration and training received and the grade of BC cases are the concern of this review. However, YI can be considered a supportive therapy for BC.