Factors affecting local progression after percutaneous cryoablation of lung tumors

Purpose: To evaluate factors predicting local tumor progression after percutaneous cryoablation of lung tumors (PCLT). Materials and Methods: Seventy-one consecutive patients with 210 tumors (11 primary and 199 metastatic pulmonary neoplasms; mean maximum diameter, 12.8 mm) were treated with 102 sessions of PCLT. Rates of local tumor progression and technique effectiveness were estimated by Kaplan-Meier method. Multiple variables were evaluated with the log-rank test, followed by uni- and multivariate multilevel analyses to identify independent risk factors, and hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. All statistical tests were two-sided. Results: Median follow-up period was 454 days (range, 79-2,467 d). Local tumor progression occurred in 50 tumors (23.8%). One-, 2-, and 3-year local progression-free rates were 80.4%, 69.0%, and 67.7%, respectively, and technique effectiveness rates were 91.4%, 83.0%, and 83.0%, respectively. Existence of a thick vessel (diameter≥3 mm) no more than 3 mm from the edge of the tumor was assessed as an independent factor (HR, 3.84; 95% CI, 1.59-9.30; P =.003) associated with local progression by multivariate analysis. Conclusions: Presence of a vessel at least 3 mm in diameter close to the tumor represents an independent risk factor for local progression after PCLT.