Patients with stage Ill non small-cell lung cancer (NSCLC) are a heterogeneous group, and not all patients are suitable for aggressive treatment approaches. This retrospective study of 122 cases of newly diagnosed stage Ill NSCLC aimed to identify the proportion of patients who were suitable for radical treatment. Only 50% were treated radically. Many patients were treated palliatively because of advanced stage, poor performance status, and significant weight loss. These data serve as a useful benchmark for the assessment of quality of care for patients with stage III NSCLC. Introduction: Outcome data from Cancer Care Ontario suggest that only 27% of patients with stage III non small-cell lung cancer (NSCLC) receive chemoradiotherapy. However, many patients are not suitable for radical treatment. This study aimed to determine the proportion of patients with stage III NSCLC suitable for radical treatment and to examine reasons for choosing a palliative approach otherwise. Patients and Methods: This was a retrospective cohort study of patients with newly diagnosed stage III NSCLC treated between July 1, 2007, and June 30, 2009, at the Juravinski Cancer Centre, Canada. Data collected included patient demographics, clinical characteristics, treatment, and outcomes. Results: A total of 122 patients with stage III NSCLC were included. Additional data on 37 patients with stage IV NSCLC and pleural effusions (previously stage IIIB) are included for comparison. Of the 122 patients, 61(50%) received radical treatment and 61 (50%) were treated palliatively. Reasons for excluding patients from radical treatment were weight loss (VVL) > 10% within 3 months of presentation (11%), performance status (PS) > 2 (16%), or combined poor PS and WL (33%). Significant comorbid health problems excluded only 15% of patients from radical treatment. The median overall survival (OS) for patients treated radically was 23.3 months versus 7.0 months for those treated palliatively. Patients with poor PS or WL > 10% had OS similar to that of patients with stage IV pleural effusion (7.1 months vs. 7.2 months). Patients with poor PS and WL > 10% had the poorest survival (3 months). Conclusion: The present data do not support extrapolating radical treatment of stage III NSCLC beyond the eligibility criteria used in clinical trials. These data serve as a benchmark for the assessment of quality of care for patients with stage III NSCLC. (C) 2014 Elsevier Inc. All rights reserved.