Inclusion Criteria:
Sub-study 1:
1. Age: 18-75 years.
2. Performance status: Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1.
3. Nodule characteristics: Single or multiple pulmonary nodules detected on thin-section CT (slice thickness ≤1.5 mm). The largest diameter of the primary lesion is ≥8 mm and ≤20 mm. For patients with multiple nodules, the maximum diameter of other lesions must be \<8 mm.
4. No clinical or imaging evidence of lymph node or distant metastasis.
5. Planned surgical resection: Patients with complete clinical data and preoperative thin-section CT; peripheral blood samples can be collected.
6. Pathological/clinical diagnosis: Definitive pathological diagnosis after surgical resection is required as the gold standard.
7. Informed consent: Patients voluntarily join this study, sign written informed consent, and agree to complete scheduled follow-up for at least 5 years.
8. Sample availability: Patients can provide sufficient peripheral blood samples as required by the study protocol. For patients undergoing surgery or biopsy, tumor tissues and adjacent normal tissue samples meeting quality requirements can be obtained.
Sub-study 2:
1. Age: 18-75 years.
2. Performance status: Able to tolerate bronchoscopic biopsy, with no contraindications to biopsy.
3. Nodule characteristics: Single or multiple pulmonary nodules detected on thin-section CT (slice thickness ≤1.5 mm). The target lesion planned for biopsy has a maximum diameter ≥8 mm and ≤30 mm.
4. Clinician assessment: Clinicians recommend bronchoscopic biopsy (including conventional bronchoscopy, endobronchial ultrasound \[EBUS\], navigational bronchoscopy, etc.) to determine the pathological nature of the pulmonary nodule.
5. Specimen and imaging: Small tissue specimens obtained during biopsy undergo three-dimensional interferometric imaging, and complete imaging data are retained.
6. Pathological/clinical diagnosis: Definitive pathological diagnosis of the small biopsy specimen is required as the gold standard.
7. Informed consent: Patients voluntarily join this study, sign written informed consent, and agree to complete scheduled follow-up for at least 5 years.
Exclusion Criteria:
Sub-study 1:
1. Concurrent immune diseases: Active autoimmune diseases (such as rheumatoid arthritis, systemic lupus erythematosus, etc.), or patients receiving long-term systemic immunosuppressants or glucocorticoids within the past 6 months.
2. Active infection: Active infections (such as active pulmonary tuberculosis, acute phase of SARS-CoV-2 infection, etc.) that may significantly affect immune status.
3. Prior anti-tumor treatment: Any form of anti-tumor therapy received within the past 6 months, including chemotherapy, radiotherapy, targeted therapy, or immune checkpoint inhibitor therapy.
4. Suspected multiple primary lung cancers where secondary lesions require simultaneous or staged intervention (surgery, ablation, radiotherapy, etc.).
5. Other malignant tumors: History of other malignant tumors within the past 3 years.
6. Severe dysfunction of major organs: Severe hepatic or renal insufficiency (judged by investigators).
7. Special population: Pregnant or breastfeeding women.
8. Poor study compliance: Any psychological, family, or social factors that prevent patients from understanding and following the study protocol and follow-up plan.
Sub-study 2:
1. Concurrent immune diseases: Active autoimmune diseases (such as rheumatoid arthritis, systemic lupus erythematosus, etc.), or patients receiving long-term systemic immunosuppressants or glucocorticoids within the past 6 months.
2. Active infection: Active infections (such as active pulmonary tuberculosis, acute phase of SARS-CoV-2 infection, etc.) that may significantly affect immune status.
3. Prior anti-tumor treatment: Any form of anti-tumor therapy received within the past 6 months, including chemotherapy, radiotherapy, targeted therapy, or immune checkpoint inhibitor therapy.
4. Special population: Pregnant or breastfeeding women.
5. Poor compliance with study or procedure: Any physical, psychological, family, or social factors that prevent patients from understanding and following the study protocol or tolerating bronchoscopy.
6. Bleeding tendency or severe coagulation disorders.
