Impact of Lazertinib Dose Modification on Effectiveness and Safety

The primary objective is to evaluate Progression Free Survival (PFS) of the group (160 mg group) in which dose reduction was performed for 12 weeks after the first administration of Lazertinib. The Secondary objectives of this study are as follows. 1. To evaluate Progression-free survival (PFS) of the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib 2. In the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib, Time-to-Treatment Discontinuation(TTD), Objective Response Rate(ORR), Disease Control Rate(DCR), Tumor shrinkage and Overall Survival(OS) is evaluated. 3. In the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib, specific reasons (adverse event name, grade, etc.) according to Lazertinib dose adjustment is evaluated. 4. To evaluate the treatment profile of Lazertinib including duration of treatment, dose adjustment, and reason for discontinuation of treatment. 5. To evaluate the safety of Lazertinib in the 240 mg and 160 mg groups