Dosimetric and Clinical Predictors of Acute Esophagitis in Lung Cancer Patients in Turkey Treated with Radiotherapy

Background: The purpose of this study was to determine the clinical and dosimetric factors associated withacute esophagitis (AE) in lung cancer patients treated with conformal radiotherapy (RT) in Turkey. Materialsand
Methods: In this retrospective review 104 lung cancer patients were examined. Esophagitis grades wereverified weekly during treatment, and at 1 week, and 1 and 2 months afterwards. The clinical parametersincluded patient age, gender, tumor pathology, number of chemotherapy treatments before RT, concurrentchemotherapy, radiation dose, tumor response to RT, tumor localization, interruption of RT, weight loss, tumorand nodal stage and tumor volume. The following dosimetric parameters were analyzed for correlation of AE:The maximum (Dmax) and mean (Dmean) doses delivered to the esophagus, the percentage of esophagus volumereceiving ≥10 Gy (V10), ≥20 Gy (V20), ≥30 Gy (V30), ≥35 Gy (V35), ≥40 Gy (V40), ≥45 Gy (V45), ≥50 Gy (V50) and ≥60Gy (V60).
Results: Fifty-five patients (52.9%) developed AE. Maximum grades of AE were recorded: Grade 1 in51 patients (49%), and Grade 2 in 4 patients (3.8%). Clinical factors had no statistically significant influence onthe incidence of AE. In terms of dosimetric findings, correlation analyses demonstrated a significant associationbetween AE and Dmax (>5117 cGy), Dmean (>1487 cGy) and V10-60 (percentage of volume receiving >10 to 60 Gy).The most significant relationship between RT and esophagitis were in Dmax (>5117 cGy) (p=0.002) and percentageof esophageal volume receiving >30 Gy (V30>31%) (p=0.008) in the logistic regression analysis.
Conclusions: Themaximum dose esophagus greater than 5117 cGy and approximately one third (31%) of the esophageal volumereceiving >30 Gy was the most statistically significant predictive factor associated with esophagitis due to RT.