Effectiveness of Erlotinib in Advanced Non-Small Cell Lung Cancer in Cases of Gefitinib Resistance after Treatment of More Than 6 Months

Background: There have been reports on the use of erlotinib in non-small cell lung cancer (NSCLC) patients after gefitinib resistance occurs, and it has been stated that erlotinib may be beneficial in patients with long stable disease (SD) previously treated with gefitinib. Patients and Methods: We retrospectively studied gefitinib-resistant NSCLC patients with favorable clinical features, who received erlotinib following disease progression after gefitinib treatment of more than 6 months. Results: A total of 21 patients with NSCLC were included. Partial response was seen in 2 cases (9%), SD in 6 cases (19%), and progressive disease (PD) in 13 cases (62%). Disease control (DC) was achieved with erlotinib in 8 cases (36%). The median survival time (MST) was 369 days in DC cases and 133 days in PD cases. There were no statistical differences between DC cases and PD cases in terms of MST relative to sex, smoking and skin rash. Conclusion: Subsequent erlotinib therapy is one of the therapeutic options in the treatment of gefitinib-resistant NSCLC in which prior gefitinib has shown long-term SD of more than 6 months.