Is yoga effective in improving psychosocial outcomes amongst cancer patients and survivors, as compared to those with no exercise prescription or on waiting list?
Date of publication of the systematic review: November 2012
Design
Systematic review of 11 randomized controlled trials (RCTs).
Participants
598 breast cancer patients and survivors (mean age range: 44 to 63 years). Ten studies recruited only female breast cancer patients, while one study also included patients with other types of cancer.
Intervention
A supervised yoga program with physical poses (yoga asanas), breathing techniques (pranayama) and relaxation or meditation (savasana or dhanya) was provided in all included studies. All yoga classes were led by experienced yoga instructors. Median program duration was seven weeks with a range of 6 weeks to 6 months.
Comparator
Comparison: Yoga versus a non-exercise or waitlist control.
In 8 studies, the yoga program was compared with a waitlist control group. In 2 studies, the control group received supportive therapy with education, counseling, or coping preparation. In one study, the control group received health education classes.
Major Outcomes
Outcome 1: Anxiety test score as measured at the end of treatment;
Outcome 2: Fatigue test score as measured at the end of treatment;
Outcome 3: General health-related quality of life (HRQoL) score as measured at the end of treatment. Higher scores indicated high quality of life.
Settings
All the included studies were conducted in outpatient settings.
Comparison    Yoga versus a non-exercise or waitlist control
Main Results
Compared to non-exercise or waitlist control, yoga showed a significant reduction on the anxiety test score (pooled standardized mean difference (pooled SMD): -0.77, 95% CI: -1.08 to -0.46) and in fatigue test score (pooled SMD: -0.51, 95% CI: -0.79 to -0.22). A significant increment on the general HRQoL score (pooled SMD: 0.37, 95% CI: 0.11 to 0.62) was also observed. All outcomes were measured at the end of treatment.
Comparison: Yoga versus non-exercise or waitlist control amongst breast cancer patients and survivors
Outcomes No. of studies (Total number of participants) Mean score/ No. of participants Heterogeneity test (I2) Pooled SMD (95% CI) Overall quality of evidence*
Intervention Comparator
1 6 (385) Not reported Not reported 58.42% -0.77 (-1.08 to -0.46) Low
2 7 (382) Not reported Not reported 43.52% -0.51 (-0.79 to -0.22) Moderate
3 5 (291) Not reported Not reported 0.00% 0.37 (0.11 to 0.62) Moderate
Key: SMD = standardized mean difference; CI = confidence interval.
Comparison    Yoga versus a non-exercise or waitlist control
Main Results
Compared to non-exercise or waitlist control, yoga showed a significant reduction on the anxiety test score (pooled standardized mean difference (pooled SMD): -0.77, 95% CI: -1.08 to -0.46) and in fatigue test score (pooled SMD: -0.51, 95% CI: -0.79 to -0.22). A significant increment on the general HRQoL score (pooled SMD: 0.37, 95% CI: 0.11 to 0.62) was also observed. All outcomes were measured at the end of treatment.
Comparison: Yoga versus non-exercise or waitlist control amongst breast cancer patients and survivors
Outcomes 1 2 3
No. of studies (Total number of participants) 6 (385) 7 (382) 5 (291)
Mean score/ No. of participants Intervention Not reported Not reported Not reported
Comparator Not reported Not reported Not reported
Pooled SMD (95% CI) -0.77 (-1.08 to -0.46) -0.51 (-0.79 to -0.22) 0.37 (0.11 to 0.62)
Overall quality of evidence* Low Moderate Moderate
Key: SMD = standardized mean difference; CI = confidence interval.
Conclusion
Benefits
Compared to non-exercise or waitlist control, yoga showed significant benefits for breast cancer patients and survivors by reducing the anxiety and fatigue test scores measured at the end of treatment. Yoga also demonstrated significant improvement on general HRQoL. For outcome 1, the overall quality of evidence is low. Further research is likely to have an important impact on our confidence in this estimate of effect. For outcomes 2 and 3, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
Five studies evaluated adverse events and provided such information in the manuscripts. Amongst these five studies, four studies reported that there were no adverse events and one study reported one case of adverse event from a participant with a history of back problems. This participant experienced a back spasm during yoga class. However, after evaluation by her physician, that participant was able to return to class and complete the intervention.
Link to Original Article
http://www.ncbi.nlm.nih.gov/pubmed/ 23181734
The synopsis is based on the following article:
Buffart LM, van Uffelen JG, Riphagen II, Brug J, van Mechelen W, Brown WJ, Chinapaw MJ. Physical and psychosocial benefits of yoga in cancer patients and survivors, a systematic review and meta-analysis of randomized controlled trials. BMC Cancer. 2012 Nov 27;12:559.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.