MD, PhD, FMedSci, FRSB, FRCP, FRCPEd

Today is WORLD CANCER DAY.

Yesterday I prepared you for this event by alerting you to a disgusting cancer scam, and today I want to contrast this with more encouraging news from the strange world of alternative medicine. So I searched Medline for a fitting, recent publication showing at least some value of an alternative therapy. Believe me, such papers are few and far between.

But here is one:

The aim of this Cochrane review was to assess effects of yoga on health-related quality of life, mental health and cancer-related symptoms among women with a diagnosis of breast cancer who are receiving active treatment or have completed treatment. The authors conducted extensive literature searches and applied no language restrictions. RCTs were eligible, if they (1) compared yoga interventions to no therapy or to any other active therapy in women with a diagnosis of breast cancer, and (2) assessed at least one of the primary outcomes on patient-reported instruments, including health-related quality of life, depression, anxiety, fatigue or sleep disturbances.

Two review authors independently collected data on methods and results. The risk of publication bias was assessed through visual analysis of funnel plot symmetry and heterogeneity between studies. Subgroup analyses were conducted for current treatment status, time since diagnosis, stage of cancer and type of yoga intervention.

Twenty-four studies with a total of 2166 participants were included, 23 of which provided data for meta-analysis. Thirteen studies had low risk of selection bias, five studies reported adequate blinding of outcome assessment and 15 studies had low risk of attrition bias. Seventeen studies that compared yoga versus no therapy provided moderate-quality evidence showing that yoga improved health-related quality of life, reduced fatigue and reduced sleep disturbances in the short term. There was an overall low risk of publication bias.

Yoga did not appear to reduce depression or anxiety in the short term and had no medium-term effects on health-related quality of life or fatigue. Four studies that compared yoga versus psychosocial/educational interventions provided moderate-quality evidence indicating that yoga can reduce depression, anxiety and fatigue in the short term. Very low-quality evidence showed no short-term effects on health-related quality of life or sleep disturbances. Three studies that compared yoga to exercise presented very low-quality evidence showing no short-term effects on health-related quality of life or fatigue. No trial provided safety-related data.

The authors concluded that moderate-quality evidence supports the recommendation of yoga as a supportive intervention for improving health-related quality of life and reducing fatigue and sleep disturbances when compared with no therapy, as well as for reducing depression, anxiety and fatigue, when compared with psychosocial/educational interventions. Very low-quality evidence suggests that yoga might be as effective as other exercise interventions and might be used as an alternative to other exercise programmes.

As I said, this is most encouraging. Many women are attracted by yoga, and the news that it can improve their symptoms is clearly positive. I have said it often, but I say it again: in supportive and palliative cancer care there might be an important role for several forms of CAM. One has to make sure though that they do not interfere with conventional treatments, and – this is very important – cancer patients must not be misled to believe that they can be used to treat or cure cancer. Finally, patients should not pitch their hopes too high: the effect sizes of alternative treatments in cancer care are invariably small or modest which means that they can help to reduce symptoms but are unlikely to get rid of them completely.

On an even more sober note, I have to reiterate that none of the trials included in the above review reported safety data (yoga is not totally devoid of adverse-effects!). This is an almost stereotypical finding when assessing clinical trials of alternative therapies. It discloses a clear and unacceptable breach of publication ethics. How can we ever get a realistic impression of the risks of alternative medicine, if adverse effects remain unreported? It is high time that researchers, authors, journal editors and reviewers get this message and behave accordingly.

2 Responses to Yoga improves quality of life, fatigue and sleep of breast cancer patients

  • The complete lack of safety data is a serious concern.

    I see yoga as comprising a psycho-social as well as an exercise element – at least when it is practised with an instructor within a group. So it makes sense that yoga would show benefits over psycho-social therapies alone. It would be interesting to know what other forms of exercise, yoga was compared with. Individual exercise, jogging for example, would lack a psycho-social component, whereas team games would benefit from both components.

    • The issues are socio-political. Yoga’s semi-religious halo-effect is enhanced by the media, celebrities and new age spiritualism. Any instructor-led Tai Chi class is more effective with less adverse effects than yoga. (See The Science of Yoga: The Risks and the Rewards by William J Broad). However, in the west, Tai Chi is tainted by a decades-long association with atheistic communist China and a complete lack of commercial success. (Granted, this association hasn’t affected the popularity of TCM.) Both Yoga and Tai Chi claim extreme non-supported benefits, healing powers, and are mired in pre-scientific nonsense, but Yoga’s ubiquitous commercial success carries a strong group inclusion placebo effect.

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