7592 Background: Percutaneous cryoablation using high resolution fluoroscopic CT guidance under local anesthesia offers a potential tool for local control of lung tumors in combination with systemic treatments. In this study, we retrospectively analyzed the safety, and efficacy of percutaneous cryoablation for lung tumors (PCLT). Methods: This study was approved by the institutional review board. From October 2002, PCLT was performed in patients who either did not oncologically fulfill the indications for resection, or refused resection. CT scan was examined every 3 months after PCLT. >20% increase in the treated lesion size was diagnosed as local failure. Survival analysis was done by Kaplan-Meier. Results: There were 147 patients (95 male, 52 female, mean age 60, 20 primary lung cancer, metastases; 29 of lung cancer, 35 of colorectal cancer, 63 of other sites). 251 sessions were done for 462 tumors. Mean tumor diameter was 18.3mm. PCLT was well tolerated in most patients. In 1 case, broncho-thoracic fistula occurred in the treated region which lead to empyema. Other complications were pneumothorax (153 sessions, 61%, chest tube required in 23 sessions), pleural effusion (160 sessions, 64%), and transient hemoptysis (82 sessions, 33%). Overall one- and two-year local control rates were 81.0% and 59.1%, respectively. Overall one- and two-year survival rates were 80.0% and 54.5%, respectively. In the 1–20 mm sized (n=362) vs. over 21mm sized (n=100) lesions, the local control rates at one year were 84% vs. 56% (p=0.0007), and at two years were 63% vs. 35% (p=0.017), respectively. There were no differences in local control between primary and metastatic tumors, carcinomas and sarcomas. Survival of patients whose lesions were limited to 1–20mm (n=89) was prolonged vs. those who had at least one over 21mm lesion (n=58) (p=0.01). However, one, and two-year survival rates did not differ significantly between these groups (one-year; 85.5% vs. 71.7% (p=0.07), two-year; 60.7% vs. 46.5% (p=0.16)). Conclusions: PCLT was minimally invasive and safe. 1–20mm tumors were good candidates. Contribution of PCLT to survival was not clear in this mixed patient population. To improve local control in over 20 mm tumors, we are computer simulating freezing kinetics to optimize the number and the positioning of the probes. No significant financial relationships to disclose.
Local Control of Metastatic Lung Tumors Treated with SBRT of 48 Gy in Four Fractions: In Comparison with Primary Lung Cancer
