title: Yoga for breast cancer patients and survivors: a systematic review and meta-analysis.
abstract: BACKGROUND
  Many breast cancer patients and survivors use yoga to cope with their disease. The aim of this review was to systematically assess and meta-analyze the evidence for effects of yoga on health-related quality of life and psychological health in breast cancer patients and survivors.
  
  
  METHODS
  MEDLINE, PsycInfo, EMBASE, CAMBASE, and the Cochrane Library were screened through February 2012. Randomized controlled trials (RCTs) comparing yoga to controls were analyzed when they assessed health-related quality of life or psychological health in breast cancer patients or survivors. Risk of bias was assessed using the Cochrane risk of bias tool. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated.
  
  
  RESULTS
  Twelve RCTs with a total of 742 participants were included. Seven RCTs compared yoga to no treatment; 3 RCTs compared yoga to supportive therapy; 1 RCT compared yoga to health education; and 1 RCT compared a combination of physiotherapy and yoga to physiotherapy alone. Evidence was found for short-term effects on global health-related quality of life (SMD = 0.62 [95% CI: 0.04 to 1.21]; P = 0.04), functional (SMD = 0.30 [95% CI: 0.03 to 0.57), social (SMD = 0.29 [95% CI: 0.08 to 0.50]; P < 0.01), and spiritual well-being (SMD = 0.41 [95% CI: 0.08; 0.74]; P = 0.01). These effects were, however, only present in studies with unclear or high risk of selection bias. Short-term effects on psychological health also were found: anxiety (SMD = -1.51 [95% CI: -2.47; -0.55]; P < 0.01), depression (SMD = -1.59 [95% CI: -2.68 to -0.51]; P < 0.01), perceived stress (SMD = -1.14 [95% CI:-2.16; -0.12]; P = 0.03), and psychological distress (SMD = -0.86 [95% CI:-1.50; -0.22]; P < 0.01). Subgroup analyses revealed evidence of efficacy only for yoga during active cancer treatment but not after completion of active treatment.
  
  
  CONCLUSIONS
  This systematic review found evidence for short-term effects of yoga in improving psychological health in breast cancer patients. The short-term effects on health-related quality of life could not be clearly distinguished from bias. Yoga can be recommended as an intervention to improve psychological health during breast cancer treatment.
authors.affiliation: Chair of Complementary and Integrative Medicine, University of Duisburg-Essen, Knappschafts-Krankenhaus, Am Deimelsberg 34a, 45276 Essen, Germany. h.cramer@kliniken-essen-mitte.de
authors.forename: Holger
authors.initials: H
authors.lastname: Cramer
authors.forename: Silke
authors.initials: S
authors.lastname: Lange
authors.forename: Petra
authors.initials: P
authors.lastname: Klose
authors.forename: Anna
authors.initials: A
authors.lastname: Paul
authors.forename: Gustav
authors.initials: G
authors.lastname: Dobos
mesh_terms: D001943:Breast Neoplasms / Q000523:psychology*; D005260:Female; D006801:Humans; D008603:Mental Health; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D017741:Survivors / Q000523:psychology*; D015013:Yoga / Q000523:psychology*