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

Abstract 

Purpose

To evaluate dose–volume histogram (DVH) parameters as predictors of radiation pneumonitis (RP) in esophageal cancer patients treated with definitive concurrent chemoradiotherapy.

Patients and methods

Thirty-seven esophageal cancer patients treated with radiotherapy with concomitant chemotherapy consisting of 5-fluorouracil and cisplatin were reviewed. Radiotherapy was delivered at 2Gy per fraction to a total of 60Gy. For most of the patients, two weeks of interruption was scheduled after 30Gy. The percentage of lung volume receiving more than 5–50Gy in increments of 5Gy (V5–V50, respectively), and the mean lung dose (MLD) were analyzed.

Results

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.

Conclusion

DVH parameters were predictors of symptomatic RP and should be considered in the evaluation of treatment planning for esophageal cancer.

Keywords: Esophageal cancer, Chemoradiotherapy, Radiation pneumonitis, Dose–volume histogram