How effective is mindfulness-based therapy in reducing anxiety and depression in patients with cancer?
Data of publication of the systematic review: November 2015
Design
Systematic review of 7 randomized controlled trials (RCTs).
Participants
A total of 888 adult participants (mean age range: not reported, overall male % range: not reported) who were diagnosed with cancer (including stage 0 cancer) were included.
Intervention
Various types of mindfulness-based interventions were used. Mindfulness-based stress reduction and art therapy were the most common (5/7 studies). The length of intervention lasted from 7 weeks (1/7 studies) to 8 weeks (6/7 studies).
Comparator
Comparison 1: Mindfulness-based therapy versus wait list, general education or usual care.
Major Outcomes
Outcome 1: Anxiety score measured by Symptom Checklist-90-Revised (SCL-90-R), Profile of Mood States Short-form Scale (POMS), Hospital Anxiety and Depression Scale (HADS) or Hamilton Anxiety Rating Scale (HAM-A). Higher scores indicated higher level of anxiety;
Outcome 2: Depression score measured by Symptom Checklist-90-Revised (SCL-90-R), Profile of Mood States Short-form Scale (POMS), Hospital Anxiety and Depression Scale (HADS) or Hamilton Rating Scale for Depression (HAM-D). Higher scores indicated higher level of depression.
Settings
The reviewers did not state whether the study was conducted in in-patient or out-patient settings.
Comparison    Mindfulness-based therapy versus wait list, general education or usual care
Main Results
In terms of anxiety reduction, the pooled standardized mean difference (SMD) indicated that the effect of mindfulness-based therapy is significantly superior, as compared to the control group (pooled SMD: -0.75, 95% Cl: -1.28 to -0.22). As for depression reduction, the pooled SMD result also showed that the effect of mindfulness-based therapy is significantly superior, as compared to the control group (pooled SMD: -0.90, 95% Cl: -1.53 to -0.26).
Comparison: Mindfulness-based therapy versus no mindfulness-based therapy among cancer patients
Outcomes No. of studies (Total no. of participants) Mean score (SD)/ No. of participants Heterogeneity test (I2) Pooled SMD (95% CI) Overall quality of evidence*
Intervention Comparator
1 7 (809) Not reported/417 Not reported/392 92% -0.75 ( -1.28 to -0.22) High
2 7 (809) Not reported/417 Not reported/392 94% -0.9 (-1.53 to -0.26) High
Keys: SD= standard deviation; SMD: standardized mean difference; CI: confidence interval.
Comparison    Mindfulness-based therapy versus wait list, general education or usual care
Main Results
In terms of anxiety reduction, the pooled standardized mean difference (SMD) indicated that the effect of mindfulness-based therapy is significantly superior, as compared to the control group (pooled SMD: -0.75, 95% Cl: -1.28 to -0.22). As for depression reduction, the pooled SMD result also showed that the effect of mindfulness-based therapy is significantly superior, as compared to the control group (pooled SMD: -0.90, 95% Cl: -1.53 to -0.26).
Comparison: Mindfulness-based therapy versus no mindfulness-based therapy among cancer patients
Outcomes 1 2
No. of studies (Total no. of participants) 7 (809) 7 (809)
Mean score (SD)/ No. of participants Intervention Not reported/417 Not reported/417
Comparator Not reported/392 Not reported/392
Pooled SMD (95% CI) -0.75 ( -1.28 to -0.22) -0.9 (-1.53 to -0.26)
Overall quality of evidence* High High
Keys: SD= standard deviation; SMD: standardized mean difference; CI: confidence interval.
Conclusion
Benefits
Mindfulness-based therapy had shown significant effect in reducing level of anxiety and depression among adult cancer patients. High heterogeneity from the pooled result however indicated that substantial differences exist among included studies. Variation in the types of mindfulness-based/ control intervention was considered the source of such difference, suggested by the sub-group analysis. Sub-group analysis also suggested that the effect of mindfulness-based therapy may not persist over long term, and that some forms of mindfulness-based interventions may be less effective for relieving anxiety and depression. For Outcome 1, the the overall quality of evidence is high. Further research is unlikely to have an important impact on our confidence in this estimate of effect. For Outcome 2, the overall quality of evidence is high. Further research is unlikely to have an important impact on our confidence in this estimate of effect.
Harms
No adverse events were reported.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/26559246
The synopsis is based on the following article:
Zhang MF, Wen YS, Liu WY, Peng LF, Wu XD, Liu QW. Effectiveness of mindfulness-based therapy for reducing anxiety and depression in patients with cancer: a meta-analysis. Medicine. 2015 Nov 1;94(45):e0897-0.


* 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.