First Line Osimertinib for EGFR Mutation-positive Non-Small Cell Lung Cancer in Real World Chinese Setting

Total of \~30 study sites are selected for conducting this observational study. Eligible patients will be prospectively and consecutively included. Therefore, the clinical practice in the selected patients group can represent the "real-world" situation in China, and the patient's medical record will be well documented and archived in those hospitals. All data defined in the protocol will be collected during the study and entered in the Electric Data Capture (EDC), being consistent to the patients' medical records. The most important bias of the study is that patients' characteristics will affect the treatment duration, efficacy and safety, such as, higher proportion of patients with WHO PS 2\~3 enroll in the study will result in shorter TTD, poorer effectiveness and higher toxicities than expected. The \~30 sites are not randomly selected and potential selection bias exists. To minimize enrolment bias, the patients who are eligible and consent to participate in the current study will be enrolled consecutively as per protocol and without personal preference from investigators. The self-selection bias may exit for the willingness and non-willingness participants. We'll try our best to discuss with the non-willingness participants to make sure the consistency/comparative between the willingness and non-willingness participants. There could be a certain percentage of patients who would lost to follow up, it is unavoidable in clinical study, and is more common in real world study. We can minimize the bias by selecting the hospitals with normative and high-quality clinical practice, trying to collect the reason of lost to follow up and enhancing patient management during the follow up. The above bias is acceptable as this is a "real-world" study. Only descriptive analysis will be performed for the primary, secondary and exploratory objectives. No statistical comparisons between subgroups will be done.