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Clinical and Dosimetric Risk Factors of Acute Esophagitis in Patients Treated With 3-Dimensional Conformal Radiotherapy for Non–Small-Cell Lung Cancer

Purpose:To analyze the clinical and dosimetric risk factors of acute esophagitis (AE) in non–small-cell lung cancer (NSCLC) patients treated with 3-dimensional conformal radiotherapy (3D-CRT). Methods and Materials:One hundred two NSCLC patients treated with 3D-CRT were retrospectively analyzed. Forty of these 102 patients analyzed were treated with concurrent chemotherapy (CCT). The median biologic effective dose of radiotherapy was 72.0 Gy. AE was scored according to the Radiation Therapy Oncology Group criteria. The clinical and dosimetric factors associated with grade 2 or worse AE were analyzed using univariate and multivariate binary logistic analysis. Results:There were no grade 4 or 5 AE observed in the 102 patients analyzed. Thirty-four of 102 patients (33.3%) developed grade 2 or 3 AE. Univariate analysis showed that clinical factors, such as lymph nodes stage (N 0/1 vs. N 2/3), pretreatment weight loss ≥5%, CCT, and the use of late-course hyperfractionated radiotherapy were significantly associated with grade 2 and 3 AE. Dose volume parameters of esophagus including mean esophageal dose, maximal esophageal dose, rV15, rV20, rV25, rV30, rV35, rV40, rV45, rV50, rV55, rV60 were also associated with AE. On multivariate forward step-wise logistic analysis, CCT, lymph nodes stage, and rV55 emerged as the statistically most significant factors of AE with OR parameters of 8.911, 4.832, and 1.083, respectively. Conclusion:CCT, lymphatic status, and rV55 were strong predictors of grade 2 or worse AE in NSCLC treated with 3D-CRT.