PREDICTORS OF ACUTE ESOPHAGITIS IN LUNG CANCER PATIENTS TREATED WITH CONCURRENT THREE-DIMENSIONAL CONFORMAL RADIOTHERAPY AND CHEMOTHERAPY

Purpose: To evaluate the risk factors for acute esophagitis (AET) in lung cancer patients treated with concurrent 3D-CRT and chemotherapy. Methods and Materials: Data from 100 patients treated with concurrent chemoradiotherapy with a mean dose of 62.05 +/- 4.64 Gy were prospectively evaluated. Esophageal toxicity was graded according to criteria of the Radiation Therapy Oncology Group. The following dosimetric parameters were analyzed: length and volume of esophagus in treatment field, percentage of esophagus volume treated to >= 10, >= 20, >= 30, >= 35, >= 40, >= 45, >= 50, >= 55, and >= 60 Gy, and the maximum (D-max) and mean doses (D-mean) delivered to the esophagus. Also, we developed an esophagitis index (EI) to account the esophagitis grades over treatment time. Results: A total of 59 patients developed AET (Grade 1, 26 patients; Grade 2, 29 patients; and Grade 3, 4 patients). V50 was associated with AET duration (p = 0.017), AET Grade 1 duration (p = 0.016), maximum analgesia (p = 0.019), esophagitis index score (p = 0.024), and AET Grade >= 1 (p = 0.058). If V50 is <30% there is a 47.3% risk of AET Grade >= 1, which increases to 73.3% if V50 is >= 30% (p = 0.008). The predictive abilities of models (sensitivity and specificity) were calculated by receiver operating characeristic curves. Conclusions: According to the receiver operating characeristic curve analysis, the 30% of esophageal volume receiving >= 50 Gy was the most statistically significant factor associated with AET Grade >= 1 and maximum analgesia (A(max)). There was an association with AET Grade >= 2 but it did not achieve statistical significance (p = 0.076). (C) 2009 Elsevier Inc.