This study is a retrospective real-world study to evaluate the efficacy of Osimertinib for patients with advanced or metastatic EGFR 20exon insertion mutation (20ins) Non-Small Cell Lung Cancer.

This is a multicenter, retrospective observational real-world study, which evaluates the efficacy of Osimertinib, between 2017 and 2022, in patients with advanced or metastatic EGFR 20exon insertion mutation (20ins) Non-Small Cell Lung Cancer. This study serves as the external control for a single arm phase II trial on JMT101 combined with Osimertinib in patients with Non-Small Cell Lung Cancer. The primary outcome measure is objective response rate (ORR).

Inclusion Criteria:

1. Locally advanced or metastatic (stage ШB-Ⅳ, 8th AJCC) NSCLC confirmed by histology or cytology;
2. The result of EGFR 20ins is positive detected by tissue, blood, pleural fluid or cerebrospinal fluid;
3. Have received osimertinib treatment after detection of EGFR 20ins;
4. Age of 18 years or above;
5. Information about tumor outcome evaluation is required at least once after osimertinib treatment (such as tumor imaging data, description of efficacy evaluation in medical records, etc.).

Exclusion Criteria:

1. Previously treated with JMT101 (Patients will be included if osimertinib treatment is before JMT101 treatment);
2. Patients harboring EGFR exon20 insertion mutation and also have other EGFR TKI-sensitizing EGFR mutations, such as G719X mutation in exon 18, exon 19 deletion mutation (19 del), exon 20 T790M or S768I mutation, exon 21 L858R mutation, or L861Q mutation.

Patients who have received osimertinib with advanced or metastatic EGFR 20exon insertion mutation (20ins) Non-Small Cell Lung Cancer.