Chemotherapy should be performed in epidermal growth factor receptor mutation-positive lung adenocarcinoma patients who had progressive disease to the first epidermal growth factor receptor-tyrosine kinase inhibitor.

After the failure of first-line epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy, some non-small cell lung cancer patients desire to receive switching with another EGFR-TKI (TKI-switching), although cytotoxic chemotherapy has been recommended as second-line therapy. It is unclear who should not receive TKI-switching in these patients. We retrospectively evaluated overall survival (OS) from the initiation of first EGFR-TKI (first-TKI) therapy in advanced lung adenocarcinoma patients with active EGFR mutations (deletion of exon 19 or L858R in exon 21) who received TKI-switching according to the best response of the first-TKI. There was no difference in the OS between patients receiving TKI-switching (n = 35) and patients receiving additional chemotherapy between the first-TKI and second-TKI therapy (n =10) (P = 0.614). Among patients receiving TKI-switching, the OS in cases with progressive disease to the first-TKI (n = 9) was shorter than that in cases with disease control to the first-TKI (n = 26) (12.7 months vs. 49.4 months, P < 0.001). Five of the nine progressive disease cases who received TKI-switching missed an opportunity to receive chemotherapy. Their OS tended to be shorter than that in patients who received chemotherapy during the whole period of anticancer therapy (12.2 months vs. 20.3 months, P = 0.060). The multivariate analysis showed that disease control to the first-TKI therapy (P = 0.005) or the presence of chemotherapy (P = 0.087) decreased the risk of mortality. Chemotherapy should be performed in patients with progressive disease to the first-TKI.