Immediate versus delayed treatment with EGFR tyrosine kinase inhibitors after first-line therapy in advanced non-small-cell lung cancer

To analyze the outcomes of patients who received TKI immediately after the first-line without progression as maintenance treatment (immediate group) vs. those received delayed treatment upon disease progression as second-line therapy (delayed group). The study included 159 no-small-cell lung cancer (NSCLC) patients who received gefitinib or erlotinib as maintenance treatment in the immediate group (85 patients) or as second-line therapy in the delayed group (74 patients). The primary end point was progression-free survival (PFS). EGFR mutation status was detected using denaturing high-performance liquid chromatography (DHPLC). PFS was 17.3 and 16.4 months in the immediate and delayed groups, respectively (hazard ratio [HR], 0.99; 95% Confidence Interval [CI]: 0.69-1.42; P=0.947). In a subgroup analysis that included only patients with EGFR mutation, however, PFS was significantly longer in the immediate group than in the delayed group (HR, 0.48; 95% CI: 0.27-0.85; P=0.012). In patients with wild type EGFR, the risk for disease progression was comparable between the two groups (HR, 1.23; 95% CI: 0.61-2.51; P=0.564). No significant difference was demonstrated between the immediate and delayed group in terms of the overall survival (OS) (26.1 months vs. 21.6 months, respectively; HR=0.53; 95% CI: 0.27 to 1.06; P=0.072). There was also no difference in the incidence of adverse events between the two groups. EGFR TKI maintenance improves PFS in patients with EGFR mutation. Prospectively designed clinical studies that compare TKI immediate vs. delayed treatment after first-line chemotherapy upon disease progression are needed.