An evidence-based review of yoga as a complementary intervention for patients with cancer.

OBJECTIVE To conduct an evidence-based review of yoga as an intervention for patients with cancer. Specifically, this paper reviewed the impact of yoga on psychological adjustment among cancer patients. METHODS A systematic literature search was conducted between May 2007 and April 2008. Data from each identified study were extracted by two independent raters; studies were included if they assessed psychological functioning and focused on yoga as a main intervention. Using a quality rating scale (range = 9-45), the raters assessed the methodological quality of the studies, and CONSORT guidelines were used to assess randomized controlled trials (RCTs). Effect sizes were calculated when possible. In addition, each study was narratively reviewed with attention to outcome variables, the type of yoga intervention employed, and methodological strengths and limitations. RESULTS Ten studies were included, including six RCTs. Across studies, the majority of participants were women, and breast cancer was the most common diagnosis. Methodological quality ranged greatly across studies (range = 15.5-42), with the average rating (M = 33.55) indicating adequate quality. Studies also varied in terms of cancer populations and yoga interventions sampled. CONCLUSIONS This study provided a systematic evaluation of the yoga and cancer literature. Although some positive results were noted, variability across studies and methodological drawbacks limit the extent to which yoga can be deemed effective for managing cancer-related symptoms. However, further research in this area is certainly warranted. Future research should examine what components of yoga are most beneficial, and what types of patients receive the greatest benefit from yoga interventions.