Lukas Radbruch, Chair of Palliative Medicine, University of Bonn, Germany
Our group has performed a systematic review on the use of fish oil (omega-3-fatty acids, n-3-FA/ eicosapentaenoic acids, EPA) in advanced cancer patients suffering from cancer cachexia, and this paper (1) has been selected by the journal, ‘Palliative Medicine’, as the editor’s choice for June 2012. I am grateful and honoured by the nomination, though I would have to confess that this is a rather typical systematic review, with 244 papers identified in the literature search and 38 selected for the final evaluation. Three systematic reviews and six randomized controlled trials contributed to the evidence.
Our experience was similar to that described by other reviews: smaller trials, often unrandomized and without control group, reported a good effect, but the results of the larger randomized controlled trials did not find a significant effect. Adverse effects were not frequent and not serious, but did limit dose escalations or even led to discontinuation of fish oil treatment in some patients. The results from the review led to a weak negative GRADE recommendation.
The review focuses only on a rather tiny area of palliative care. However, it becomes much more interesting if it is considered in the context of the European Palliative Care Research Collaborative (EPCRC). The EPCRC had aimed to produce clinical guidelines on the management of pain, depression and cachexia in advanced cancer. However, the development of the cachexia guideline sparked a lot of discussion on definition and assessment of cachexia in cancer patients, and on the target group. A consensus on the definition of cachexia and a classification system were produced by other EPCRC workgroups and were integrated in the guidelines. Even though the studies evaluated in the scoping reviews for the guidelines did not provide the information required for the definition or classification of cachexia, an expert consensus on most recommendations was possible. Only the use of fish oil and of vitamins and supplements was evaluated as controversial by the expert group, resulting in the systematic review that is now published in ‘Palliative Medicine’.
The cachexia guidelines have been discussed extensively among the EPCRC experts, with the major criticism that the available literature does not differentiate between different stages of cachexia and different stages of the cancer trajectory. There is clearly a need for more research on cachexia in advanced cancer patients receiving palliative care, and these studies should pay vigorous attention to definition and classification of cachexia.
1. Ries A, Trottenberg P, Elsner F, Stiel S, Haugen D, Kaasa S and Radbruch L. A systematic review on the role of fish oil for the treatment of cachexia in advanced cancer: An EPCRC cachexia guidelines project. Palliat Med 2012 June 26 (4); 294-304. (EAPC Members and registered users of the EAPC website can download a free copy of this article and other ‘editor’s choice’ papers from the EAPC website.