The study is aimed o evaluate the diagnostic performance and treatment guidance of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) combined with transbronchial mediastinal cryobiopsy (EBUS-TBMCB) in patients with mediastinal metastases of lung cancer.

A traditional method, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), will serve as control. Enrolled patients will be randomly assigned to two groups: the experimental group, which will undergo EBUS-guided transbronchial mediastinal cryobiopsy (EBUS-TBMCB) following EBUS-TBNA, and control group, which will undergo EBUS-TBNA alone. Biopsy specimens from both groups will be analyzed by pathologists. All patients will be followed up to confirm the diagnosis and to document any complications. The diagnostic yield for lung cancer and the incidence of procedure-related adverse events will be compared between the two groups.

Inclusion Criteria:

1. Aged ≥18 years;
2. Presence of at least one mediastinal lesion (short-axis diameter ≥10 mm) confirmed by thin-slice chest CT;
3. Patients who have not undergone prior mediastinal biopsy and require further mediastinal biopsy to confirm etiology or pathological subtype, meeting at least one of the following criterias:

(1) suspected lung cancer diagnosed by two senior physicians; (2) confirmed lung cancer (requiring mediastinal staging); (3) recurrent lung cancer; 4.Patients must have completed all required preoperative laboratory tests and necessary examinations (e.g., cardiac ultrasound, CTA) to rule out contraindications; 5. Patients are informed and capable of providing written informed consent.

Exclusion Criteria:

1. Presence of severe cardiopulmonary disease, coagulation disorders, massive hemoptysis, poor tolerance to anesthesia, or other contraindications related to bronchoscopy;
2. Intraoperative endobronchial ultrasound exploration of the lesion failed to detect the target lesion despite > 20 minutes of attempts;
3. Lesions identified as abscesses or cysts;
4. Presence of mental illness, severe neurosis, or other conditions that preclude the provision of informed consent;
5. Patients who have participated in other clinical trials within 3 months;
6. Any other conditions considered to be inappropriate to be involved in this trial.