Patients' survival in lung malignancies treated by microwave ablation: our experience on 56 patients

Abstract

Objectives: We retrospectively evaluated percutaneous CT-guided microwave (MW) ablation safety and efficacy in unresectable lung malignancies focusing on patients' survival.

Materials and methods: All procedures were approved by the hospital ethical committee. From 2008 to 2012 we treated 69 unresectable lesions (44 lung cancer, 25 lung metastases) in 56 patients (35 men/21 women; mean age: 61.5 years). Treatment was performed under CT guidance using 14 G needles with a 3 cm active tip and a 55 W MW generator (Vivawave Microwave Coagulation System; Valley Lab). Treatment was performed at 45 W for 6-10 min. Patients were scheduled for a 3 and 6 month CT follow-up to evaluate lesion diameter and enhancement. Survival rate was evaluated by Kaplan-Meier analysis.

Results: Ablation procedures were completed according to protocol in all patients. Pneumothorax occurred in 18 patients and 8 required chest tube. Four lesions (all >4.3 cm) were retreated 20 days after the ablation because of peripheral focal areas of residual tumor. Follow-up CT evaluation showed a decrease in maximum diameter in 44/69 lesions (64%) and in 42/59 lesions (71%) at 3 and 6 months, respectively. In all cases no pathologic enhancement was observed. Cancer-specific mortality yielded a survival rate of 69% at 12 months, 54% at 24 months and 49% at 36 months, respectively. An estimate mean for survival time was 27.8 months with a standard error of 2.8 months (95% confidence interval: 22.4-33.2 months).

Conclusion: Based on our experience, MW ablation seems to represent a potential safe and effective percutaneous technique in the treatment of lung malignancies. MW ablation may improve survival in patients not suitable to surgery.