A systematic review of N-3 and N-6 polyunsaturated fatty acid concentration in childhood cancer patients and associated clinical outcomes

Abstract

Background: This systematic review evaluated primary research to establish blood omega-3 polyunsaturated fatty acids (n-3 PUFA); eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and omega-6 polyunsaturated fatty acids (n-6 PUFA); arachidonic acid (AA) concentration. The effectiveness of their supplementation on clinical and nutritional outcomes and associations between their concentration and clinical and nutritional outcomes were also evaluated.

Methods: Electronic databases were searched (no restriction-Dec 2018) with no language restrictions. We included studies of cancer patients aged < 18 years and reporting supplementation and/or concentration of EPA, DHA and AA. Evidence was critically appraised employing the CASP tool.

Findings: Three studies (n = 84) met the inclusion criteria, mainly of weak quality and heterogeneous in both study designs and outcomes measured. The overall median(range) n-3 and n-6 PUFA concentration were; EPA: 0.4 (0.24 - 0.4%), DHA: 1.66 (1.3 - 1.68%), AA: 7.01 (6.5 - 7.3%) and AA/EPA: 18.7 (171 - 29.2%). EPA%, DHA% and AA% were all lower than the references 0.45 - 0.77%, 2.22 - 3.76% and 7.91 - 10.46% respectively, whilst AA/EPA% was higher than the reference (< 14.59%). Both higher intake and blood concentration of EPA and DHA may reduce weight loss during initial treatment, whilst a high ratio of AA/EPA may be associated with lower BMI centiles.

Interpretation: EPA and DHA may be beneficial in children with cancer. High-quality population-based longitudinal cohort studies and clinical trials are urgently warranted.