Influence of thoracic radiotherapy on exhaled nitric oxide levels in patients with lung cancer

Abstract

Background: To determine the physiological role of exhaled nitric oxide (NO) in patients with lung cancer. Methods: We investigated changes in exhaled NO levels in 29 patients undergoing thoracic radiation therapy with or without chemotherapy. The exhaled NO level was assessed using a chemiluminescence analyzer. Results: The level of exhaled NO was higher in patients with lung cancer before treatment than in controls. With radiotherapy, the exhaled NO level decreased for patients undergoing 40 Gy irradiation and post-radiotherapy. However, five patients showed elevated levels of exhaled NO three times or more than that before radiotherapy. Three of these patients showed signs of radiation pneumonitis. However, none of the other patients showed signs of radiation pneumonitis (p = 0.002). Conclusion: Radiation therapy can lower exhaled levels of NO and the levels of exhaled NO may be a useful index for the early prediction of radiation pneumonitis.