Analysis of dose-volume histogram parameters for radiation pneumonitis after definitive concurrent chemoradiotherapy for esophageal cancer.

Abstract

To evaluate dose-volume histogram (DVH) parameters as predictors of radiation pneumonitis (RP) in esophageal cancer patients treated with definitive concurrent chemoradiotherapy. Thirty-seven esophageal cancer patients treated with radiotherapy with concomitant chemotherapy consisting of 5-fluorouracil and cisplatin were reviewed. Radiotherapy was delivered at 2 Gy per fraction to a total of 60 Gy. For most of the patients, two weeks of interruption was scheduled after 30 Gy. The percentage of lung volume receiving more than 5-50 Gy in increments of 5 Gy (V5-V50, respectively), and the mean lung dose (MLD) were analyzed. Ten (27%) patients developed RP of grade 2; 2 (5%), grade 3; 0 (0%), grade 4; and 1 (3%), grade 5. By univariate analysis, all DVH parameters (i.e., V5-V50 and MLD) were significantly associated with grade 2 RP (p < 0.01). The incidences of grade 2 RP were 13%, 33%, and 78% in patients with V20s of 24%, 25-36%, and 37%, respectively. The optimal V20 threshold to predict symptomatic RP was 30.5% according to the receiver operating characteristics curve analysis. DVH parameters were predictors of symptomatic RP and should be considered in the evaluation of treatment planning for esophageal cancer.