高达20%的非小细胞肺癌患者携带肿瘤特异性驱动突变，可以通过酪氨酸激酶抑制剂有效治疗。然而，对于EGFR外显子18的罕见缺失插入突变，关于酪氨酸激酶抑制剂的疗效几乎没有足够的证据。对于临床医生来说，应用酪氨酸激酶抑制剂的一个特别挑战不仅是诊断突变，还需要解释具有不明确治疗意义的罕见突变。因此，我们提出了一例EGFR外显子18的p.Glu709_Thr710delinsAsp不确定治疗相关性的65岁高卡路里男性肺腺癌患者的病例。该患者最初接受了两个周期的标准铂类化疗，没有任何治疗反应。在给予Osimertinib作为第二线治疗后，患者显示持久的部分缓解，持续了12个月。与治疗相关的毒性反应仅限于轻度血小板减少，随着Osimertinib剂量的减少而停止。据我们所知，这是关于使用Osimertinib有效治疗这种特定突变的首次报告。因此，我们希望讨论Osimertinib作为EGFR外显子18的p.Glu709_Thr710delinsAsp突变肺腺癌的可行治疗选项。版权所有 © 2023 Cekay，Arndt，Dumitrascu，Savai，Braeuninger，Gattenloehner，Steiner，Roller，Tello，Hattar，Seeger，Sibelius，Grimminger和Eul。

Up to 20% of all non-small cell lung cancer patients harbor tumor specific driver mutations that are effectively treated with tyrosine kinase inhibitors. However, for the rare EGFR deletion-insertion mutation of exon 18, there is very little evidence regarding the effectiveness of tyrosine kinase inhibitors. A particular challenge for clinicians in applying tyrosine kinase inhibitors is not only diagnosing a mutation but also interpreting rare mutations with unclear therapeutic significance. Thus, we present the case of a 65-year-old Caucasian male lung adenocarcinoma patient with an EGFR Exon 18 p.Glu709_Thr710delinsAsp mutation of uncertain therapeutic relevance. This patient initially received two cycles of standard platinum-based chemotherapy without any therapeutic response. After administration of Osimertinib as second line therapy, the patient showed a lasting partial remission for 12 months. Therapy related toxicities were limited to mild thrombocytopenia, which ceased after dose reduction of Osimertinib. To our knowledge, this is the first report of effective treatment of this particular mutation with Osimertinib. Hence, we would like to discuss Osimertinib as a viable treatment option in EGFR Exon 18 p.Glu709_Thr710delinsAsp mutated lung adenocarcinoma.Copyright © 2023 Cekay, Arndt, Dumitrascu, Savai, Braeuninger, Gattenloehner, Steiner, Roller, Tello, Hattar, Seeger, Sibelius, Grimminger and Eul.