Skeletal Muscle Depletion Is Associated with Reduced Plasma (n-3) Fatty Acids in Non-Small Cell Lung Cancer Patients

Upwards of 50% of newly diagnosed advanced lung cancer patients have severe muscle wasting (sarcopenia). Supplementation with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in advanced cancer has been shown to attenuate lean tissue wasting. However, the relationship between muscle mass and plasma (n-3) fatty acids in the absence of supplementation is unclear. We aimed to determine how plasma phospholipid (n-3) fatty acids relate to sarcopenia and change in muscle mass in non-small cell lung cancer patients receiving chemotherapy. Computed tomography images were used to measure muscle mass. Patients were classified as sarcopenic or nonsarcopenic based on sex-specific cutpoints. Change in muscle mass during chemotherapy (2.5 mo) was calculated and patients were divided into quartiles based on the rate of muscle loss or gain. Patients with sarcopenia had lower plasma EPA (16.7 ± 2.1 μmol/L vs. 31.6 ± 4.4 μmol/L; P = 0.001), DHA (36.6 ± 4.0 μmol/L vs. 55.3 ± 4.0 μmol/L; P = 0.003), and sum (n-3) fatty acids (63.6 ± 5.6 μmol/L vs. 95.0 ± 7.7 μmol/L; P = 0.002) than nonsarcopenic patients. Patients with maximal muscle loss (mean - 3.5 kg) had lower plasma EPA (12.2 ± 3.3 μmol/L vs. 35.0 ± 7.1 μmol/L; P = 0.03), DHA (26.9 ± 8.7 μmol/L vs. 59.6 ± 5.3 μmol/L; P = 0.01), and sum (n-3) fatty acids (57.8 ± 13.5 μmol/L vs. 104.6 ± 11.1 μmol/L; P = 0.005) compared with patients who were gaining muscle (mean +1 kg). Plasma (n-3) fatty acids are depleted in cancer patients with sarcopenia, which may contribute to accelerated rates of muscle loss.