The goal of this observational study is to determine the most accurate tumor size measurement method for T-staging and prognostic assessment in lung cancer with cystic airspaces (LCCA). The main questions it aims to answer are:

• What is the optimal T-staging approach for accurately classifying lung cancer with cystic airspaces （LCCA) and predicting patient outcomes?
• How do imaging features of cystic lesions correlate with their pathological characteristics?
• What is the relationship between imaging features of cystic airspace-associated lesions and patient prognosis?
• Can optimizing the T-staging method improve clinical decision-making in patients with LCCA?

Inclusion Criteria:

1. Histologically confirmed non-small cell lung cancer (NSCLC), as verified by biopsy or postoperative pathological examination;
2. Patients who have undergone surgical lung resection;
3. Patients with complete preoperative chest CT imaging data;
4. Preoperative chest CT showing a well-defined gas-containing (air-filled) cystic component within the tumor.

Exclusion Criteria:

1. History of pulmonary diseases that could produce cystic lung lesions (e.g., tuberculosis, pulmonary fungal infections, bullae, emphysema, Lymphangioleiomyomatosis [LAM], or Birt-Hogg-Dubé [BHD] syndrome);
2. Systemic anti-tumor therapies, including chemotherapy, radiotherapy, or targeted therapies (such as monoclonal antibodies, small-molecule tyrosine kinase inhibitors, among others), were administered prior to enrollment;
3. Patients with concurrent other malignancies;
4. Patients with missing or poor-quality preoperative chest CT imaging data.

Patients with LCCA who underwent surgical treatment in the Second Xiangya Hospital of Central South University