Effect of YOCAS yoga on sleep, fatigue, and quality of life: A URCC CCOP randomized, controlled clinical trial among 410 cancer survivors

Reporter: Arpi Thukral, MD
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 5, 2010

Presenter: K.M. Mustian
Affiliation: University of Rochester Medical Center, Rochester, NY


  • It is well known that fatigue and impaired sleep quality (SQ) are side effects often seen in cancer survivors, which can interfere with quality of life (QOL) and the ability to perform daily activities.
    • There is an ongoing need to find interventions to help reduce these debilitating side effects.
  • The term yoga is derived from the Sanskrit root "yuj", meaning "to control", "to yoke" or "to unite”, and refers to a mental and physical discipline of controlling one’s mind.
    • There are many different types of yoga practiced in the US.
    • Yoga is traditionally believed to have beneficial effects on physical and emotional health.
  • The effects of yoga have been explored in a number of patient populations, and in recent years, a few small studies have been performed to examine the effects of yoga among cancer patients and survivors; however, these studies have limitations including:
    • Large heterogeneity of patient population
    • Many different types of yoga used which may not be routinely practiced in the US
    • Various outcome measurements used
    • Non-standardization of yoga teaching
  • The purpose of this study was to conduct a nationwide, multi-site, phase II/III randomized, controlled, clinical trial examining the efficacy of yoga for improving SQ, fatigue and QOL among cancer survivors.
    • The Community Clinical Oncology Program (CCOP) is a network for conducting cancer prevention and treatment clinical trials by community medical practitioners.
    • This study was conducted through the University of Rochester (UR) Cancer Center Community Clinical Oncology Program (CCOP) Research Base and took place in 9 community cancer centers.


  • Primary Aim: to examine the efficacy of yoga intervention on improvement of SQ
  • Secondary Aims: to examine the efficacy of yoga intervention on improvement of fatigue and QOL
  • Eligibility criteria:
    • Survivors of non-metastatic cancer having undergone prior standard cancer treatment (including surgery, chemotherapy, and/or radiation therapy)
    • Completion of cancer treatments 2-24 months prior to enrollment
    • Level 3 or greater sleep disturbance on symptom inventory scale of 0-10 (10 being greatest sleep disturbance)
    • Age > 21 years
    • English language fluency
    • Written informed consent
    • No participation in yoga during the previous 3 months
  • Exclusion criteria:
    • Metastatic disease
    • Sleep apnea
  • Patients were randomized to one of two arms: 1) standard follow up care and monitoring (control arm) and 2) standard follow up care plus the 4-week yoga intervention (yoga arm).
    • The yoga intervention was based on the UR Yoga for Cancer Survivors (YOCAS) program consisting of pranayama (breathing exercises), 18 gentle Hatha and Restorative yoga asanas (postures) and meditation focusing on mindfulness.
    • Duration of yoga: 75 minute sessions twice a week for 4 weeks (8 total sessions)
    • Hatha and Restrorative types of yoga were chosen because they have been shown to have greatest impact based on previous studies, and they are widely available forms of yoga.
    • Standardization of yoga intervention was provided through the following mechanisms:
      • Highly-involved URCC CCOP yoga consultant
      • Yoga alliance certified instructors
      • Yoga instructional DVD and instructional manual for instructors
  • Standard measurement tools such as the PSQI, MFSI, and FACIT were used to assess for sleep quality, fatigue, and QOL, respectively.
  • SQ, fatigue and QOL were assessed pre- and post-intervention.


  • A total of 410 cancer survivors were accrued in this study and randomized to the 2 treatment arms: 204 survivors were enrolled on the control arm and 206 on the yoga arm.
  • Demographics: 96% of patients were female, 75% were breast cancer survivors, 93% were Caucasian, and the mean age of patients was 54.
  • 84% of patients had PSQI score of >5 at baseline and this was not statistically different between the 2 groups.
  • Compliance: 86% of survivors randomized to the yoga arm attended > or equal to 5 yoga sessions.
  • After four weeks of twice-weekly sessions, patients in the yoga arm reported greater improvement in sleep quality (22% vs. 12%), reduced incidence of clinically impaired sleep (31% vs. 16%) and less daytime sleepiness (29 % vs. 5%) compared with the control group. (P<0.005 for all variables)
  • Reduction of daytime sleepiness (29% vs. 5%) and reduction of sleep medication use (21% decrease vs. a 5% increase in use) were also statistically significant. Reduction in medication use was defined as sleep medication use once a week vs. more than once a week.
  • The investigators used an analysis of covariance (ANCOVA) method to examine the change in SQ, fatigue, and QOL between the 2 groups from baseline to post-intervention.
  • ANCOVAs with baseline values as covariates revealed significant differences in SQ, fatigue and QOL (all p<0.05) between groups at post- intervention, with patients in the yoga arm experiencing improved SQ and OQL and decreased fatigue.

Authors’ Conclusions:

  • This study demonstrated that the YOCAS yoga intervention in cancer survivors over 4 weeks significantly improved SQ, fatigue, and QOL as compared to the control group.
  • The authors note that the yoga intervention also helped to reduce sleep medication use and daytime sleepiness among survivors.
  • The authors state that clinicians should consider prescribing the YOCAS program for survivors reporting impaired sleep and fatigue.

Clinical Implications

  • This well-designed, randomized study provides interesting data regarding the use of yoga for the treatment of sleep disturbances and fatigue in cancer patients.
    • The authors were able to show a statistically significant improvement in both primary and secondary outcomes with the use of yoga.
  • The strengths of this trial include:
    • Largest randomized study examining yoga in cancer patients to date.
    • Patients were highly selected, most being female breast cancer survivors.
    • The study was limited to patients who were not receiving chemotherapy, which could have confounded outcomes such as fatigue and QOL.
    • Standardization of yoga instruction.
  • A previous study by Moadel et. al. published in JCO 2007, examined the role of yoga in breast cancer in an urban cancer center and found no significant difference in QOL, but a “feeling of social well-being” declined more in the control group than the yoga group.
    • Patients that were not receiving chemotherapy did show a benefit in QOL with yoga, suggesting that selection of patient population may play a role in outcome.
  • The results of this study did differ from the results of this recent study by Moadel et. al. mentioned above. The current study had a larger study population and a highly selected group of patients, which may have contributed to the difference in results.
  • Although this is a positive trial, one may question how clinically applicable this data is. There are many challenges involved in conducting a yoga intervention for cancer patients. These include:
    • Cost and availability of yoga classes
      • One solution may the use of a DVD based yoga class.
    • Compliance with yoga program
    • Difficulty associated with measurement of self-reported adherence to intervention, especially with DVD system.
    • Standardization of yoga instruction/type of yoga across facilities.
  • Other limitations of the study presented here include:
    • Standard questionnaires were used to assess QOL, fatigue, and SQ. Patient reporting is a very subjective measure, and introduces bias. Slightly more objective measures such as formal sleep studies may be of use in this setting.
    • Additionally, there was no data provided on potential toxicities associated with yoga in these patients. Injuries from yoga in breast cancer patients who may already have lymphaedema is a possibility.
    • Patients in this study group may be self-selected or interested in yoga or other interventions to help QOL. This may cause them to demonstrate a greater benefit. It also becomes difficult to control for patients in the control group seeking out yoga or exercise programs to reduce fatigue.
    • The intervention was given for only 4 weeks. It is unclear if yoga would have continued effects or if patients would need to continue the intervention for a longer period of time.
  • In conclusion, the data presented in this study is shows potential to impact care of cancer survivors. Sleep disturbance is a major side effect of cancer therapy that hinders survivors’ quality of life and treatments for these symptoms is essential. The use of yoga and other lifestyle modifications is an area that is exciting and warrants further investigation.
  • Future studies should focus on areas such as:
    • Duration/timing of yoga
    • Yoga in different types and stages of cancer
    • Effect on men vs. women
    • Effect of type of yoga
    • Timing of outcome measurements

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