Neoadjuvant Lazertinib Therapy in EGFR-Mutation Positive Lung Adenocarcinoma Detected by BALF Liquid Biopsy

Inclusion Criteria: 1. Age ≥ 19 years 2. Patients with suspected lung cancer on chest CT findings 3. Patients with the following EGFR gene mutations in the test on bronchoalveolar lavage fluid: E19Del, L858R alone or concurrent rare EGFR gene mutations (T790M, G719X, exon 20 insertion, S768I) 4. Patients whose tumor can be completely resected by surgery: patients with stage I-IIIB, or stage IVA who has single metastasis 5. Patients not previously treated with EGFR-TKIs such as gefitinib, erlotinib, afatinib, dacomitinib 6. Patients with the measurable lesion of 1 cm or more according to RECIST v1.1 7. Eastern Cooperative Oncology Group (ECOG) 0-1 8. EGFR-TKIs (gefitinib, erlotinib, afatinib,dacomitinib) naive patients 9. Patients with adequate pulmonary and heart function for surgery 10. Adequate organ function defined as Hemoglobin ≥ 9.0g/dL Absolute neutrophil count ≥ 1500/mm3 Platelet ≥ 100,000 /mm3 Serum creatinine≤ normal range\*1.5x Aminotransferase/Alkaline phosphatase ≤normal range\*2.5x Total bilirubin ≤1.5 mg/dL Liver metastasis: Aminotransferase/Alkaline phosphatase ≤ normal range\* 5x Bone metastasis Alkaline phosphatase ≤ normal range\* 5x 11. Female patients with childbearing potential should be using adequate contraceptive measures. Female patients must have evidence of non-child-bearing potential(Post-menopausal defined as aged more than 50 years and amenorrheic for at least 12 months following cessation of all exogenous hormonal treatments) 12. Men with a female partner of childbearing potential must have either had a prior vasectomy or agree to use effective contraception for at least 14 days prior to administration of the first dose of study treatment, during the study, and for 3 months following the last dose of Lazertinib. Exclusion Criteria: 1. Uncontrolled active interstitial lung disease 2. Pathologically confirmed N3 disease 3. Uncontrolled stage III-IV other malignancy 4. Uncontrolled Hypertension, Congestive Heart failure with New York Heart Association(NYHA) ≥ 3, acute myocardial infarct history within 6 months before screening. 2nd- 3rd Atrio-Ventricular(AV) block or complete AV block 5. Gastrointestinal diseases (e.g. Chron's disease, ulcerative colitis) or malabsorption syndrome that would impact on drug absorption 6. Active infection requiring ongoing treatment(e.g. active Hepatitis B virus, Hepatitis C virus or Human immunodeficiency virus) 7. History of hypersensitivity to active or inactive excipients of Lazertinib or drugs with a similar chemical structure. 8. No ability to comply with protocol requirements.