This multicenter, non-interventional, prospective, observational study aimed to determine whether patients' attitude to chemotherapy is an independent prognostic factor for survival in patients with advanced non-small cell lung cancer (NSCLC) who are treated with gemcitabine-platinum. Chemonaive patients (n = 1895) with stage IIIB or IV NSCLC not amenable to curative surgery or radiotherapy were treated with a combination of gemcitabine plus cisplatin/carboplatin and followed for a maximum of 18 months. Patients' attitude to treatment was measured on a 5-point scale and responses were used to assign patients to one of the three need categories: A, maximum extension of survival with the acceptance of high toxicity (60.0% of patients); B, maximum extension of survival only if coupled with normal lifestyle (26.1%); C, relief of symptoms (13.8%). Median survival varied significantly among the need categories (A = 13.00 months, B = 15.70 months, C = 15.33 months; log-rank test P=0.0415). Patient attitude to treatment (need categories) was not a significant prognostic factor for survival after adjusting for known prognostic factors (P=0.0503). After adjusting for baseline differences, patients in this study had a significantly lower risk of death than patients in three randomized trials (hazard ratio 0.879; 95% confidence interval: 0.775, 0.998; P=0.0458). In conclusion, in this observational study, patient attitude to chemotherapy was not an independent prognostic factor of survival. (C) 2009 Elsevier Ireland Ltd. All rights reserved.