Dosimetric correlations of acute esophagitis in lung cancer patients treated with radiotherapy.

PURPOSE: To evaluate the factors associated with acute esophagitis in lung cancer patients treated with thoracic radiotherapy.

METHODS AND MATERIALS: We examined 35 patients with non-small-cell lung cancer (n = 27, 77%) and small-cell lung cancer (n = 8, 23%) treated with thoracic radiotherapy between February 2003 and November 2004. The median patient age was 70 years (range, 50-83 years). The disease stage was Stage I in 2 patients (6%), Stage II in 1 (3%), Stage IIIa in 10 (28%), Stage IIIb in 9 (26%), and Stage IV in 9 (26%); 4 patients (11%) had recurrent disease after surgery. A median dose of 60 Gy (range, 50-67 Gy) was given to the isocenter and delivered in single daily fractions of 1.8 or 2 Gy. With heterogeneity corrections, the median given dose to the isocenter was 60.3 Gy (range, 49.9-67.2 Gy). Of the 35 patients, 30 (86%) received concurrent chemotherapy consisting of a platinum agent, cisplatin or carboplatin, combined with paclitaxel in 18 patients (52%), irinotecan hydrochloride in 7 (20%), vincristine sulfate and etoposide in 2 (5%), vinorelbine ditartrate in 1 (3%), etoposide in 1 (3%), and docetaxel in 1 patient (3%). Three of these patients underwent induction therapy with cisplatin and irinotecan hydrochloride, administered before thoracic radiotherapy, and concurrent chemotherapy. Esophageal toxicity was graded according to the Radiation Therapy Oncology Group criteria. The following factors were analyzed with respect to their association with Grade 1 or worse esophagitis by univariate and multivariate analyses: age, gender, concurrent chemotherapy, chemotherapeutic agents, maximal esophageal dose, mean esophageal dose, and percentage of esophageal volume receiving >10 to >65 Gy in 5-Gy increments.

RESULTS: Of the 35 patients, 25 (71%) developed acute esophagitis, with Grade 1 in 20 (57%) and Grade 2 in 5 (14%). None of the patients had Grade 3 or worse toxicity. The most significant correlation was between esophagitis and percentage of esophageal volume receiving >35 Gy on univariate (p = 0.002) and multivariate (p = 0.018) analyses.

CONCLUSION: The percentage of esophageal volume receiving >35 Gy was the most statistically significant factor associated with mild acute esophagitis.