A systematic review on the role of fish oil for the treatment of cachexia in advanced cancer: An EPCRC cachexia guidelines project

Background: The European Palliative Care Research Collaboration is developing clinical guidelines on cachexia in patients with advanced cancer. 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 was performed as part of the guideline development. Methods: The systematic literature search in Medline on the use of fish oil/n-3-FA/EPA identified 244 papers, with 38 publications included in the final evaluation. Some smaller trials, often unrandomized and without a control group, reported a good effect of n-3-FA in patients with advanced cancer and cachexia. However, the results of the larger randomized controlled trials could not support the positive results, as they mostly did not find a significant effect. Results: Adverse effects such as abdominal discomfort, fish belching, fish aftertaste, nausea and diarrhoea were reported with a low incidence. No serious adverse effects were documented, but adverse effects often had an impact on quality of life. This often limited dose escalations or even led to discontinuation of n-3-FA. Conclusion: There is not enough evidence to support a net benefit of n-3-FA in cachexia in advanced cancer. On the other hand, adverse effects were infrequent, with no severe adverse effects. The results from the review led to a weak negative GRADE recommendation.