N-3 Long-Chain Polyunsaturated Fatty Acids, Eicosapentaenoic and Docosahexaenoic Acid, and the Role of Supplementation during Cancer Treatment: A Scoping Review of Current Clinical Evidence

Abstract

This scoping review examines the evidence for n-3 long-chain polyunsaturated fatty acid [LCPUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] supplementation in clinical cancer therapy. A comprehensive literature search was performed to identify relevant clinical intervention studies conducted through August 2020. Fifty-seven unique cancer trials, assessing EPA and/or DHA supplementation pre- or post-treatment, concomitant with neoadjuvant chemotherapy, radiation or surgery, or in palliative therapy were included. Breast, head and neck, gastrointestinal, gastric, colorectal/rectal, esophageal, leukemia/lymphoma, lung, multiple myeloma and pancreatic cancers were investigated. Across the spectrum of cancers, the evidence suggests that supplementation increased or maintained body weight, increased progression-free and overall survival, improved overall quality of life, resulted in beneficial change in immune parameters and decreased serious adverse events. Taken together, the data support that EPA and/or DHA could be used to improve outcomes important to the patient and disease process. However, before incorporation into treatment can occur, there is a need for randomized clinical trials to determine the dose and type of n-3 LCPUFA intervention required, and expansion of outcomes assessed and improved reporting of outcomes.

Keywords: clinical; docosahexaenoic acid (DHA); eicosapentaenoic acid (EPA); immune; intervention; outcomes.

Figure 1

Flow chart of search and screening results for review inclusion.

Figure 2

Overview of outcomes reported on the effects of n-3 supplementation compared to control or baseline status in clinical trials. Abbreviations used: CEA, carcinoembryonic antigen; CRP, C-reactive protein; DHA, docosahexaenoic acid, DFS, disease-free survival, EPA, eicosapentaenoic acid, IFN, interferon; IL, interleukin; MMP, matrix metalloproteinase, OS, overall survival, PGE2, prostaglandin E2; PFS, progression-free survival; QOL, quality of life; SOD, super oxide dismutase; TNF, tumor necrosis factor; VEGF, vascular endothelial growth factor.