OBJECTIVES: This study examined care consumption and management costs among patients who received second- or third-line oral erlotinib therapy for non small-cell lung cancer (NSCLC). METHODS: The study involved two observational cohorts of NSCLC second- or third-line treated patients. In the first, created in 2005 (before erlotinib became available), the patients received IV chemotherapy alone (IV cohort, 233 patients), while the patients in the second cohort, created in 2006, received oral erlotinib (oral cohort, 166 patients). Only direct costs (payer's perspective) were taken into account. RESULTS: Treatment lasted a similar length during second-line treatment but was significantly longer in the oral cohort during third-line therapy line (p <0.008). The rate of conventional hospitalization was not different between the two cohorts. In contrast, during 100 days of management, the patients in the oral cohort tended to spend less time in hospital during second-line treatment (p = 0.057), and the difference was statistically significant during third-line treatment (p<0.05). Regardless of the line of treatment, the oral cohort made significantly fewer stays in daycare clinics (p<0.001), and received significantly less antiemetic treatment (p<0.0001), erythropoietin (p<0.005) and G-CSF (p<0.001), but required more treatment for skin rash (p<0.001). Monthly management costs per patient in the IV and oral cohorts were respectively 3126 and 2750 euros during second-line treatment and 3026 and 2823 euros during third-line treatment (no significant difference). A sensitivity analysis showed that the results in the IV cohort were dependent on the cost of chemotherapy. One limit of this study is that transport costs were not taken into account. CONCLUSION: In oral cohort, the cost of erlotinib is compensated by the reduction of daycare hospitalization costs and the limited cost of adverse events medications. These results must be validated by prospective observational studies focusing on quality of life and the time spent in hospital.