LAUSR

Abstract Background Osimertinib is a standard treatment for non-small cell lung cancer(NSCLC) with common and T790M EGFR mutation and efficacy for brain metastasis is reported. However there are only a few reports regarding efficacy or other metastatic sites such as pleural effusion, bone metastasis, and pulmonary metastasis. Methods We retrospectively analyzed efficacy of osimertinib in 84 patients who had NSCLC with common and T790M EGFR mutation and received osimertinib at our hospital between March 2016 to December 2018. Results Baseline characteristics of the 84 patients is as follows. There were 33 males and 51 females. The median age was 64 years. ECOG PS was 0, 1 or 2 in 19 (22.6%), 56 (66.7%) and 9 (10.7%) patients, respectively. Twenty three patients (27.4%) had pleural effusions, 32 patients (38.1%) had brain metastasis, 42 patients (50%) had bone metastasis, and 58 patients (69.0%) had pulmonary metastasis. For all patients, the response of osimertinib were 48 PR (57.1%), 24 SD (28.6%), 6 PD (7.1%), 6 NE (7.1%). Median time to treatment failure (TTF) was significantly shorter in patients with pleural effusions than those without (9.5 vs 11.1 months, respectively, p = 0.01). Regarding bone metastasis, brain metastasis, or lung metastasis, there was no significant difference in TTF (p = 0.52, p = 0.11, p = 0.88, respectively). Conclusion Osimertinib might be less potent for pleural effusion.