Résumé : Epidermal growth factor receptor tyrosine kinase inhibitors represent a new treatment option for patients with advanced nonsmall cell lung cancer (NSCLC). This retrospective study examined to what extent previous clinical trial experience matches large-scale Western community implementation of this treatment. In the Belgian expanded access programme, the data from 513 patients with advanced or metastatic NSCLC, not suitable for further chemotherapy and receiving oral gefitinib 250 mg.day(-1) until disease progression, death or unacceptable toxicity, were analysed. The median (range) duration of gefitinib treatment was 2.3 months (0.0-32.7). Its use was predominantly in second- or third-line treatment. The overall response and disease control rates were 8.9 and 41.2%, respectively. In univariate analysis, response was more common in females and never-smokers. In multivariate analysis, female sex was the only significant predictive factor (odds ratio (OR) (95% confidence interval (CI)) 0.329 (0.129-0.839)). Symptom improvement was reported in 108 patients of whom 32 (29.6%) had an objective response, 66 (61.1%) experienced disease stabilisation and 10 (9.3%) progressed. Gefitinib was well tolerated; only 7.8% of the patients reported grade 3 or 4 toxicity. The overall median survival was 4.7 months, with a 1-yr survival rate of 21%. Survival was strongly influenced by a better performance status (PS) (good PS: hazard ratio (HR) (95%CI) 0.110 (0.077-0.157)) and adenocarcinoma with bronchioloalveolar carcinoma features histology (HR (95%CI) 0.483 (0.279-0.834)). In conclusion, the activity of gefitinib was confirmed in the present large Western community implementation study. Response, present in a small subgroup, led to a rewarding survival and could be predicted by sex only. Baseline performance status and adenocarcinoma with bronchioloalveolar carcinoma features histology were significant factors for survival.