Abnormalities in lipid metabolism have been frequently observed in cancer and are associated with a poor prognosis. However, a detailed, longitudinal characterization of fatty acid status is lacking. This study aimed to assess plasma phospholipid fatty acids before chemotherapy, immediately after and 1 month following chemotherapy in a group of 50 patients newly diagnosed with lung cancer and explore factors which may contribute to aberrations in fatty acids. Their mean ± SD characteristics: age 64 ± 8.5 years, 75% advanced stage disease, body mass index 27.0 ± 5.4 kg/m², 6 month weight loss -4.6 ± 6.1%. Compared to patients with early stage disease, patients with advanced disease had abnormal fatty acid profiles including significantly lower (P