Long-Term Clinical Outcome of Intensity-Modulated Radiotherapy for Inoperable Non-Small Cell Lung Cancer: The MD Anderson Experience

Purpose: In 2007, we published our initial experience in treating inoperable non-small-cell lung cancer (NSCLC) with intensity-modulated radiation therapy (IMRT). The current report is an update of that experience with long-term follow-up. Methods and Materials: Patients in this retrospective review were 165 patients who began definitive radiotherapy, with or without chemotherapy, for newly diagnosed, pathologically confirmed NSCLC to a dose of ≥60 Gy from 2005 to 2006. Early and late toxicities assessed included treatment-related pneumonitis (TRP), pulmonary fibrosis, esophagitis, and esophageal stricture, scored mainly according to the Common Terminology Criteria for Adverse Events 3.0. Other variables monitored were radiation-associated dermatitis and changes in body weight and Karnofsky performance status. The Kaplan-Meier method was used to compute survival and freedom from radiation-related acute and late toxicities as a function of time. Results: Most patients (89%) had Stage III to IV disease. The median radiation dose was 66 Gy given in 33 fractions (range, 60–76 Gy, 1.8–2.3 Gy per fraction). Median overall survival time was 1.8 years; the 2-year and 3-year overall survival rates were 46% and 30%. Rates of Grade ≥3 maximum TRP (TRPmax) were 11% at 6 months and 14% at 12 months. At 18 months, 86% of patients had developed Grade ≥1 maximum pulmonary fibrosis (pulmonary fibrosismax) and 7% Grade ≥2 pulmonary fibrosismax. The median times to maximum esophagitis (esophagitismax) were 3 weeks (range, 1–13 weeks) for Grade 2 and 6 weeks (range, 3–13 weeks) for Grade 3. A higher percentage of patients who experienced Grade 3 esophagitismax later developed Grade 2 to 3 esophageal stricture. Conclusions: In our experience, using IMRT to treat NSCLC leads to low rates of pulmonary and esophageal toxicity, and favorable clinical outcomes in terms of survival.