Friday, 4 March 2016
Not only is the evidence for the benefits of psychosocial interventions extremely mixed, but some cancer patients and their relatives have understandably railed against the "cruel" suggestion that they might live longer if only they looked on the bright side and didn't get so stressed.
It's against this background that researchers in South Korea have conducted a new review of the effects of psychological interventions on cancer patients' survival time. Their study published in Psychology and Health is a meta-analysis which means that they have combined the results from prior research to get an overview of the current evidence base.
The researchers, led by P.J. Oh at Sahmyook University, found over 4,000 studies that looked promising, published between 1966 and 2014. However, once the researchers included only those papers that were randomised controlled trials and that included interventions delivered by professionals and had data on patient survival times, they were left with just 15 suitable studies conducted in five different countries and involving a total of 2940 participants with an average age of 52 years. The studies involved different types of intervention including psychoeducational programmes, CBT and supportive-expressive groups (a form of psychodynamic psychotherapy). The patients in the studies had a range of different cancers at different stages, including breast cancer, gastrointestinal cancer and melanoma.
Looking at all the data from all 15 studies, there was no evidence that psychosocial interventions prolong the lives of cancer patients. However, because of the huge variation between the studies in terms of the interventions and the types of patient, the researchers also broke down the evidence into sub-categories and here the picture was more promising. For example, by excluding six studies that had exclusively involved patients with late-stage cancer, the researchers found that psychosocial interventions reduced the likelihood of patients dying during the course of the study (follow up times varied from one to 12 years) by 27 per cent, on average. "Stress reduction, if that is the causal mechanism, may have to occur earlier to achieve positive results," the researchers said.
Other details to emerge included the finding that a positive benefit of psychosocial interventions was only apparent for studies involving patients with gastrointestinal cancer, although there was too little data to speculate as to whether this finding is meaningful or a chance result. Comparing the different types of intervention, the strongest positive evidence was for one-on-one programmes compared with groups, and for psychoeducational approaches delivered by medical doctors and nurses, as opposed to psychologists or other non-medical professionals.
Psychoeducational interventions involve health education, coping skills training, stress management and psychological support, and the researchers speculated their benefit might arise through a mixture of reducing patients' distress, encouraging healthy behaviours and treatment compliance. "In addition, supportive social relationships might buffer the effects of cancer-related stress on immunity and thereby facilitate the recovery of immune mechanisms and may be important for cancer resistance," they said.
Critics may question whether it is reasonable to combine results from such varied studies as was done in the current meta-analysis, and the researchers acknowledged that many of the studies were not as robust in their methodology as they should be. However, they end their review on a positive note: "a tentative conclusion can be reached," they said, "that psychosocial interventions offered at early stage may provide enduring late benefits and possibly longer survival."
Oh, P., Shin, S., Ahn, H., & Kim, H. (2016). Meta-analysis of psychosocial interventions on survival time in patients with cancer Psychology & Health, 31 (4), 396-419 DOI: 10.1080/08870446.2015.1111370
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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