18G Ultrafine Cryoablation Needle for Coaxial Biopsy and Cryoablation of Pulmonary Nodules

All participants will be assigned to a single intervention group. Under CT guidance, a coaxial needle will be positioned near the pulmonary nodule. Biopsy specimens will be obtained before cryoablation. An 18G ultrafine cryoablation needle will then be introduced through the same coaxial tract, and image-guided cryoablation will be performed according to lesion size, shape, and location. A second biopsy may be obtained after ablation. Staged or supplemental ablation is allowed when clinically required. Follow-up assessments include chest CT, safety evaluation, and long-term disease and survival follow-up for up to 36 months.

Inclusion criteria

• Age 18 years or older.
• One or more pulmonary nodules measuring 3 cm or less on chest CT and considered highly suspicious for malignancy after multidisciplinary review.
• The participant is unsuitable for or declines surgery and radiotherapy after multidisciplinary evaluation and shared decision-making.
• A safe percutaneous access route is available, and the planned ablation zone can cover the target lesion.
• Eastern Cooperative Oncology Group performance status of 0 to 2.
• Expected survival of at least 12 months.
• The participant or legally authorized representative voluntarily provides written informed consent.

Exclusion criteria

• Platelet count below 50 × 10^9/L, clinically significant bleeding tendency, or uncorrectable coagulation disorder.
• Severe pulmonary fibrosis, pulmonary hypertension, or other severe cardiac, pulmonary, hepatic, renal, neurologic, or systemic organ dysfunction that makes the procedure unsafe.
• Uncontrolled local or systemic infection, including uncontrolled infection near the lesion or access site, or fever above 38.5°C.
• Poorly controlled malignant pleural effusion.
• Anticoagulant or antiplatelet therapy cannot be safely managed before the procedure according to institutional policy.
• Pregnancy or a plan to become pregnant during the study.
• Active serious psychiatric illness that may interfere with informed consent or study participation.
• Participation in another clinical study within 30 days before enrollment.
• Any other condition that, in the investigator's judgment, makes participation inappropriate.