Objectives Survival analysis, technical success, safety and imaging follow-up of malignant pulmonary nodules treated with microwave and radio-frequency ablation.

Materials/Methods Between July 2010 and July 2012, 28 patients, 14 female, mean age 61 years (31–87) with 54 pulmonary malignancies of mean diameter 18 mm (6–59mm) underwent computed tomography (CT)-guided thermal ablation (radio-frequency ablation for two lesions, microwave ablation for the remainder). Bronchogenic carcinoma was treated in 15 patients, metastatic tumour in the remainder (tumours were diagnosed by biopsy (67%) and or PET/CT). Technical success was defined as needle placement in the intended lesion without death or serious injury. Adequacy of ablation was assessed at 24 hours on contrast-enhanced CT. Circumferential solid or ground glass opacification > 4mm was deemed adequate, and >5mm was deemed ideal. Patients were followed with contrast-enhanced CT 3 monthly until death, or local tumour recurrence; Recurrence was identified by enlargement of the zone, the development of contrast enhancement in part of the zone, or a change in the shape of the ablation zone as a result of enlargement of one area. Survival rate was evaluated by Kaplan-Meier analysis

Results Thermal ablation was technically successful in 98% (n = 50). Mean ablation duration was 5.2 minutes (1–24 minutes). 19(68%) patients developed a pneumothorax post procedure, 7 (25%) required a chest drain. 30-day mortality rate was 0%. The mean hospital stay was 1.3 days (1–7 days). Local recurrence was only identified in one patient at a median follow up of 12 months. The 1-year survival for all cause mortality was 68%; cancer-specific mortality yielded a 1-year survival of 75%.

Conclusions Thermal ablation of pulmonary malignancies is a safe, successful technique. Local control rates and survival analysis are encouraging, with rapid treatment times, performed as a single day-case procedure advantageous over stereotactic beam radiotherapy.