Abstract:

Objective To evaluate the correlation of clinical factors and radiation therapy factors with incidence of radiation pneumonitis in patients with lung cancer treated with intensity-modulated radiation therapy (IMRT). Methods The medical records of 63 patients with lung cancer treated with IMRT were retrospectively analysed. The dose volume histogram of treatment program and clinical influencing factors were compared between patients with radiation pneumonitis and those without radiation pneumonitis. The clinical parameters were observed, which included pathology, tumor location, concurrent chemotherapy, dose and pattern of radiation, and the dosimetric factors included V5, V10, V15, V20, V25, V30, V35, V40 and mean lung dose. The effect of above factors on the incidence of radiation pneumonitis was analysed. Results Among the 63 patients, 19 experienced radiation pneumonitis. Univariate analysis revealed that total dose and small cell lung cancer as pathological type were significantly associated with the incidence of radiation pneumonitis. Multivariate analysis indicated that only V5 was the risk factor of radiation pneumonitis. Conclusion Pathological type and V5 value should be considered in the IMRT for lung cancer, and low dose may also cause injury to sensitive lung tissues.

Key words: lung cancer, intensity-modulated radiation therapy, radiation pneumonitis, dose volume histograms, clinical factors