Eight of 8932 patients (0.09%) had EGFR T854A mutation....Interestingly, all EGFR T854A mutations were co-occurred with EGFR L858R mutation in cis….Five of the eight patients received treatment of osimertinib. Four patients achieved partial response, and one had stable disease, resulting in an overall objective response rate of 80% and disease control rate of 100%. The median progression-free survival of patients who received osimertinib was 10 months....Presence of EGFR T854A mutation was rare in NSCLC patients and our retrospective study provides clinical evidence that osimertinib may be an effective treatment to improve survival outcomes in patients with EGFR T854A.