Continuation of Epidermal Growth Factor Tyrokine Kinase Inhibitor with or Without Chemotherapy Beyond Gradual Progression in Non-Small Cell Lung Cancer Patients.

e20531 Background: Several studies have demonstrated that continuous administration of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) could provide addtitional survival benefit for advanced non-small cell lung cancer (NSCLC) patients who had gained benefit from prior EGFR TKI therapy. However, whether EGFR TKI combined with chemotherapy could prolong survival in patients of gradual progression is still unclear. The present study was conducted to evaluate the clinical outcome of continuation of EGFR TKI monotherapy or combination with chemotherapy in such a clinical setting. Methods: We retrospectively reviewed our single center database and analyzed all NSCLC patients treated with EGFR TKI at our institutions from Feb 2012 to Nov 2015. All eligible patients must meet the criteria of gradual progression. The main clinical endpoints were time interval between PFS1 (gradual progression or death) and PFS2 (off-EGFR TKI progression) and overall survival (OS). Results: A total of 51 patients were included in our study. Baseline characteristics were well balanced. Exon 19 deletion mutations and L858R point mutations were detected in 16 and 8 patients, respectively. Twenty one, 22 and 8 patients were treated with EGFR TKI in the 1st, 2nd and 3rd line setting. The median PFS1 for EGFR TKI monotherapy group and combination group was 366 and 249 days, respectively (P = 0.017). The median PFS2 was 532 and 395 days (monotherapy vs combination), respectively (P = 0.009). The time interval from PFS1 to PFS2 was 161 and 122 days (monotherapy vs combination), respectively (HR = 1.93, 95% CI: 0.96 - 3.89, P = 0.065). The median OS was not reached in the monotherapy group, and 799 days in the combination group (HR = 1.56, 95% CI: 0.62 - 3.91, P = 0.344). There were no statistical differences between two groups in terms of the time interval from PFS1 to PFS2 and OS. Conclusions: Our results showed that compared with EGFR TKI monotherapy, the combination of chemotherapy beyond gradual progression may not confer survival benefit to NSCLC patients, although there were no statistical significance. Further prospective studies are warranted. Clinical trial information: NCT01998061.