Relationship between acute radiation pneumonitis and dosimetric factors in intensity-modulated radiotherapy for lung caner: a study based on different lesion locations

Objective: To explore the dosimetric, factors for acute radiation pneumonitis (ARP) after restricted field intensity-modulated radiotherapy (IMRT) for lung caner based on different lesion locations. Methods: A retrospective study of ARP was performed among 113 patients with lung cancer undergoing restricted field IMRT from 2013 to 2015. The Radiation Therapy Oncology Group criteria wee used to grade ARP. Comparison was made by χ² test and independent sample t-test. The logistic regression model was used for multivariate analysis. The receiver operating characteristic curve was used to predict the optimal cut-off value. Results: The statistical analysis showed that the incidence of ARP was not related to clinical factors. The V₅ of the diseased lung was an independent predictor of the incidence of grade > 2 ARP (P = 0.016). The optimal cut-off value of V₅ was 71.6%. According to the lesion locations in patients, the rV₅ was an independent predictor of the incidence rates of ARP in the right lung, upper right lung, and right middle/lower lung (P = 0.020, 0.020, 0.049) with optimal cut-off values of 66.2%, 74.7%, and 87.5%, respectively. The aV₅ was an independent predictor of the incidence of ARP in mediastinal lung cancer (P = 0.009) with an optimal cut-off value of 66.73%. Conclusions: The V₅ of the diseased lung is an independent predictor of the incidence of grade > 2 ARP. In terms of the different lesion locations, the rV₅ is an independent predictor of the incidence rates of grade > 2 ARP in the right lung, upper right lung, and right middle/lower lung. The aV₅ is an independent predictor of the incidence of ARP in mediastinal lung cancer. (authors)