[Timing the change of chemotherapy for non-small cell lung cancer].

Lung cancer patients thus far have been given a non-treated period called "treatment holiday", followed by 4-6 courses of platinum-doublet. Now, maintenance therapy has attracted much attention after the approval of pemetrexed and bevacizumab. Treatments with both drugs are effective, with mild toxicity. However, it was not established how to apply maintenance therapy to patients. Maintenance therapy with pemetrexed requires the selection of patients by the efficacy of induction therapy(PR or SD), performance status, and the tendency of disease progression. In contrast, bevacizumab monotherapy should be applied to all patients having PR or SD, because the therapy is less toxic and no predictive factor has been identified. On the other hand, the efficacy of EGFR-TKI therapy for patients with EGFR activating mutation has been established. EGFRTKIs are key drugs for patients with EGFR-mutation, and are recommended as standard first-line therapy. I consider that chemotherapies are the second important drugs for prolonging patient survival. It has not been confirmed which is superior, the first-line therapy with EGFR-TKIs or the second line. But when EGFR-TKIs are administered in first-line, we should change TKIs to chemotherapy immediately after determination of PD on the basis of RECIST. When EGFR-TKIs are administered after chemotherapy in the second line or more line, continuation of EGFR-TKIs after PD can be accepted as long as there is no obvious exacerbation.