The following inclusion criteria must be met in order to be enrolled in the stage 1:

Patient:

• Provide informed consent
• 18 years or older
• Diagnosed with stage IV NSCLC
• Currently receiving or previously received 1L EGFR-TKI treatment
• Without communication barrier
• Do not exhibit signs of cognitive impairment that would prevent participation in an interview, as informally assessed during screening by the recruiter

Physician:

• Provide informed consent
• Specialized in departments of medical oncology, respiratory medicine, or thoracic surgery at tertiary hospitals
• Manage at least 3 stage IV NSCLC patients with 1L EGFR-TKI per month
• Holding the title of associate chief physician or higher

The following inclusion criteria must be met in order to be enrolled in the stage 2:

Patient:

• Provide informed consent
• 18 years or older
• Diagnosed with stage IV NSCLC
• Currently receiving or previously received 1L EGFR-TKI treatment
• Without communication barrier
• Do not exhibit signs of cognitive impairment that would prevent participation in a survey, as informally assessed during screening by the recruiter

Physician:

• Provide informed consent
• Specialized in departments of medical oncology, respiratory medicine, or thoracic surgery at tertiary hospitals
• Manage at least 3 stage IV NSCLC patients with 1L EGFR-TKI per month
• Holding the title of attending physician or higher

Not applicable.