Zhang, J., Yang, K.H., Tian, J.H., & Wang, C.M. (2012). Effects of yoga on psychologic function and quality of life in women with breast cancer: A meta-analysis of randomized controlled trials. Journal of Alternative and Complementary Medicine, 18, 994-1002. 

STUDY PURPOSE: To evaluate the effects of yoga in women with breast cancer

TYPE OF STUDY: Meta-analysis and systematic review

DATABASES USED: PubMed, EMBASE, Cochrane Library, Chinese Biomedical Literature Database, and Chinese Digital Journals Database

KEYWORDS: Yoga or asana and breast cancer, and additional breast cancer terms

INCLUSION CRITERIA: Randomized controlled trial (RCT) comparing yoga or yoga-based intervention with a control group

EXCLUSION CRITERIA: Studies that included yoga as part of a larger intervention

TOTAL REFERENCES RETRIEVED: N = 86

EVALUATION METHOD AND COMMENTS ON LITERATURE USED: Cochrane handbook was used for evaluation of methodological quality. Randomization was unclear in all but one study, and only one study blinded investigators. Three studies did not report complete outcome data, and dropouts were substantial percentages of the sample in all studies

• FINAL NUMBER STUDIES INCLUDED: N = 6 included in meta-analysis  
• SAMPLE RANGE ACROSS STUDIES: Range = 18-164
• TOTAL PATIENTS INCLUDED IN REVIEW: N = 382
• KEY SAMPLE CHARACTERISTICS: All were women with breast cancer aged ≥ 30 years.

Anxiety was measured in two studies, and meta-analysis showed no significant effect. Depression was measured in two studies, and meta-analysis showed no significant effect of yoga on depression. Fatigue was examined in five studies with no significant effect shown in meta-analysis. Sleep was measured in two studies with no significant effect shown in meta-analysis. Overall, quality of life was the only outcome measure in which a significant effect was seen from meta-analysis (SMD = 0.27, p = .03).

Insufficient evidence exists to advocate for the use of yoga in patients with breast cancer. No significant effects were seen related to anxiety, depression, sleep disturbance, or fatigue in these patients.

A small number of studies were included, and all had methodological limitations. Yoga interventions differed and varied in frequency and duration.

Insufficient evidence exists to show a benefit of yoga for women with breast cancer. High quality research is needed to evaluate the effects of yoga for symptom management.