CT-guided percutaneous conformal cryoablation for lung carcinoma

Objective To investigate the safety, efficacy and feasibility of CT-guided percutaneous conformal cryoablation for lung cancer. Methods The inclusion criteria were: (1) Poor respiratory function and aged patients who can not bear the thoracic surgical operation. (2) Peripheral lung cancer involving the pleura and chest wall which can not be resected. (3) Residual tumor after other comprehensive treatment. (4) Focal lung cancer but the patient refused surgical resection. The exclusion criteria were: (1) Multifocal lesions. (2) Lesion close to mediastinum with possible risk of vessel injury. (3) Severe impairment of pulmonary functions, the maximum voluntary ventilation is less than 39%. (4) Repeated cough or dyspnea, can not cooperate with the procedure. (5) Poor systemic conditions, cachexia or bleeding. Totally, 76 lung carcinoma lesions on 66 patients were treated by CT-guided percutaneous conformal cryoablation using 17 G cryoprobes. The maximum diameters of the tumors ranged from 1.5 cm to 1.6 cm. For the tumors with the maximum diameter less than 3.0 cm, they were treated by double-needle clamping cryoablation. For those with the maximum diameter between 3.0 and 5.0 cm, they were treated by multiple-needle conformal cryoablation. For those with the maximum diameter larger than 5.0 era, they were treated with multipleneedle conformal cryoablation, with the needle distance less than 1.5 cm. All the patients were followed-up 6 to 24 months after the procedure using contrast-enhanced CT to evaluate the tumor size and enhancement. Results For 18 cases with the maximum diameters less than 3.0 cm, CT scan during the procedure showed that the frozen areas extended beyond the edge of the lesions more than 1.0 cm, the lesion attenuated, narrow-band-like encircled translucency around the lesions and target sign with ground-glass density of the peripheral lung tissue. There was no enhancement during the first 1 st、3 rd month follow-up, only fibrosis scar in 6 th month follow-up. Seven patients were followed up 2 years later, 5 of them have no recurrence or metastasis, one had mediastinal lymphopathy and one had bone metastasis 1 year later. For the 22 cases with maximum diameters between 3.0 cm and 5.0 cm, CT scan during procedure showed the frozen areas covered the lesions, lobulation and spiculation disappeared and the tumor size slightly enlarged. The lesions volume reduced during 1 st and 3 rd month follow-up. Nine cases were followed up for 2 years, 4 had no recurrence, 3 were stable and 2 had remote metastasis. For 26 cases with the maximum diameters larger than 5.0 cm, CT scan during the procedure showed the frozen areas covered 70%-90% of the tumor, there was no frozen damage to the surrounding lung tissue. Twenty-six patients had postoperative radiotherapy and chemotherapy. Follow-up in the 6 th month showed that 9 lesions decreased, 11 were stable and 6 progressed with remote metastasis. Complications included hemoptysis (3), bloody sputum (26), pneumothorax (19). Five pneumothorax were treated by close drainage and recovered 5 days. Conclusion CT-guided percutaneous conformal cryoablation is an effective and minimal invasive procedure for the lung carcinoma treatment. Key words: Lung neoplasms; Cryotherapy