Impact of serum eicosapentaenoic acid/arachidonic acid ratio on overall survival in lung cancer patients treated with pembrolizumab: a pilot study

This pilot study analyzed the dietary patterns of patients with non-small cell lung cancer undergoing initial pembrolizumab, an immune checkpoint inhibitor (ICI), treatment in the month before treatment. Serum fatty acid fractions and their associations with ICI treatment efficacy were also investigated. The results showed that long-term survivors (those who survived for >= 3 years) consumed significantly more seafood than short-term survivors (those who survived for < 3 years). Furthermore, the serum levels of eicosapentaenoic acid (EPA) as well as the ratio of EPA to arachidonic acid (EPA/AA) were higher in the long-term survivors than those in the short-term survivors. The group with a high serum EPA/AA ratio had a significantly higher overall survival rate after ICI treatment than the group with a low serum EPA/AA ratio. In conclusion, higher dietary seafood consumption may improve OS in lung cancer patients treated with ICI and the serum EPA/AA ratio may be a useful biomarker for determining the efficacy of ICI treatment. Thus, supplements that increase the serum EPA/AA ratio could serve as new nutritional interventions for enhancing the efficacy of ICI treatment. However, further large-scale case and intervention studies are required.