To evaluate the clinical factors to predict the efficacy of osimertinib treatment in NSCLC patients with EGFR-T790M mutations, we first categorized two groups: patients in whom the PFS with osimertinib treatment was more than 8 months were classified into the “long PFS group,” and patients in whom the duration was less than 8 months were classified into the “short PFS group”. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.