The goal of this observational study is to describe the clinical epidemiological characteristics and disease spectrum distribution of newly diagnosed primary lung cancer patients in a real-world setting. The main questions it aims to answer are:

What is the current status of lung cancer epidemiology, including age, gender, smoking history, and pathological subtype distribution? How do different lung cancer screening behaviors (e.g., overscreening, underscreening, guideline-concordant, and precision screening) influence the capture rate of the "curative time window" (defined as adenocarcinoma in situ (AIS)/minimally invasive adenocarcinoma (MIA) or pure Ground-Glass Nodules (GGNs) stage)? What are the economic costs and cumulative radiation exposure associated with these different screening patterns? Researchers will compare these screening behavior groups to evaluate the efficacy of the "low-age, low-frequency" screening strategy in capturing early-stage lung cancer.

Participants will be asked to:

Provide their medical history and detailed records of pre-diagnosis lung cancer screening (including CT scan history).

Allow researchers to collect and analyze their clinical, pathological, and radiological data from hospital records and medical databases.

Complete a questionnaire regarding their screening history and health-related behaviors.

Inclusion Criteria:

• Histologically confirmed primary lung cancer within the past year (surgical or biopsy pathology).
• Patients capable of clearly recalling or providing medical and physical examination history prior to diagnosis.

Exclusion Criteria:

• Recurrent lung cancer or metastatic lung tumors.
• Severe lack of critical clinical data (e.g., inability to provide pathological type or stage).
• Patients with cognitive impairment or severe mental illness who cannot cooperate with the questionnaire.

The study population consists of patients with pathologically confirmed primary lung cancer who are newly diagnosed within the past year at Fudan University Shanghai Cancer Center and participating multicenter sites. The population includes individuals across various age groups, smoking statuses, and risk profiles, who are capable of providing detailed medical history and pre-diagnosis screening records. Patients with recurrent lung cancer, metastatic disease, or those unable to complete the study questionnaires due to cognitive or mental health conditions are excluded.