Impact of radiotherapy and chemotherapy on biomarkers of oxidative DNA damage in lung cancer patients

Objectives: To assess oxidative damage to DNA during lung cancer (LC) treatments. Design and methods: Urinary levels of 8-oxoguanine (8-oxoGua) and levels of 8-oxo-2'-deoxyguanosine (8-oxodG) from urine and whole blood were determined in 36 non-cancer controls and 65 LC patients before any treatments. Samples were also obtained of LC patients during and after radiotherapy (RT, n = 33) and chemotherapy (CT, n = 16). Results: Stage IV LC patients had higher urinary 8-oxoGua and 8-oxodG levels than patients with stage I-III disease (P=0.044 and p=0.034, respectively). Urinary 8-oxodG levels increased during the first week of RT (p < 0.001). Nuclear 8-oxodG increased during RT and 3 months after start of RT. Nuclear 8-oxodG levels also rose between the first two CT cycles (p=0.043), and urinary 8-oxodG levels during the sixth CT cycle (p=0.009). Conclusions: Urinary DNA damage biomarker levels may be associated with LC stage. Both RT and CT increase the parameters of DNA oxidation. (c) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.