Management of medical inoperable and tyrosine kinase inhibitor-naive early-stage lung adenocarcinoma with epidermal growth factor receptor mutations: A retrospective multi-institutional analysis.

e21082 Background: The clinical value of combined local radiation and epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) and for medical inoperable and TKI-naïve early-stage lung adenocarcinoma patients with EGFR mutations is not yet determined. In this study, we aimed to pool multi-institutional data to compare the therapeutic effect of EGFR-TKI alone and combined radiation and TKI on the survival outcomes in this patient subgroup. Methods: 132 cases of medical non-operable stage I to III EGFR mutant lung adenocarcinoma were retrospectively reviewed based on data from 5 centers. Among the patients, 65 cases received combined radiation and EGFR-TKI therapy (R+TKI) (49.2%), while 67 cases had EGFR-TKI (50.8%) treatment alone. All patients were followed until death. Results: For R+TKI group, the median overall survival (OS) after primary therapy was 42.6 months, while that of the TKI alone group was 29.4 months (log-rank p < .001). In terms of progression-free survival (PFS), the median PFS in these two treatment groups were 24 months and 14.7 months respectively (log-rank p < .001). Multivariate analysis showed that R+TKI was independently associated with improved OS (adjusted HR: 0.420; 95% CI, 0.287 to 0.614; p < .001) and PFS (adjusted HR: 0.420; 95% CI, 0.291 to 0.605; p < .001) compared to TKI alone. Subgroup analysis confirmed the significant OS benefits in stage III patients and RFS benefits in stage II/III patients. Conclusions: Upfront radiation to primary sites with TKI to follow was a feasible option for patients with EGFR-mutant medical inoperable non-small-cell lung carcinoma (NSCLC) during first-line EGFR-TKI treatment, with significantly improved PFS and OS compared with TKI alone