Late Complications of High-Dose (≥66 GY) Thoracic Conformal Radiation Therapy in Combined Modality Trials in Unresectable Stage III Non-small Cell Lung Cancer

Background: Combined modality treatment is the standard of care for patients (pts) with unresectable stage III non-small cell lung cancer. Dose escalation of radiotherapy is one strategy used to improve locoregional control and survival, but it increases the risk of both early and late treatment related toxicities. Methods: From May 1996 to August 2004, a total of 112 stage III non-small cell lung cancer pts were treated on 4 phase I/II or phase II trials to assess the safety and feasibility of high-dose (60-90 Gy) thoracic conformal radiotherapy. Patients who received >= 66 Gy (n = 88) were included in an analysis of late complications. Late complications were defined as complications that developed or persisted >= 90 days postradiotherapy. The classic lung toxicities of radiation pneumonitis and fibrosis were not included in this analysis. Results: Of the 88 patients included in this analysis of late complications, 21 patients (24%) developed a late complication and a total of 28 late complications were observed. The late complications were: pulmonary (n = 5; bronchial stenosis [n = 3] and fatal pulmonary hemoptysis [n = 2]), esophageal (n = 6), cardiac (n = 9) osseous (n = 6), and second primary tumor (n = 2). The median Survival for all patients enrolled oil the 4 trials (with 95% confidence interval [CI]) was 24.7 months (18.1-30.4 months), and the 5-year overall survival (with 95% CI) was 24% (16-32%). Data to assess for radiographic evidence of local progression were available for 99 patients, and the rate of local progression was 43% (95% CI 34-53%). Conclusions: High-dose thoracic conformal radiotherapy is feasible and results in promising survival outcomes. Late complications occur in a minority of patients.