Mark William Little MBBS, MSc, Presenter: Nothing to Disclose

Daniel Yiu Fai Chung MBBS, FRCR, Abstract Co-Author: Nothing to Disclose

Eoghan John Patrick McCarthy MBBCh, Abstract Co-Author: Nothing to Disclose

James Henry Briggs MBChB, FRCR, Abstract Co-Author: Nothing to Disclose

Philip Boardman MBChB, Abstract Co-Author: Nothing to Disclose

Fergus Vincent Gleeson MBBS, Abstract Co-Author: Alliance Medical Ltd Consultant

Ewan Mark Anderson MBBCh, Abstract Co-Author: Nothing to Disclose

Survival analysis, technical success, safety and imaging follow-up of malignant pulmonary nodules treated with a novel high power microwave ablation system.

Over a three year period, 55 patients, 33 male, mean age 64 years (31-88) with 92 unresectable pulmonary malignancies of mean diameter 18mm (6-59mm) underwent computed tomography (CT)-guided percutaneous microwave ablation in 72 ablation sessions. Primary non-small cell bronchogenic carcinoma was treated in 28 lesions, whilst metastatic tumors were ablated in the remainder (colorectal=28, renal=9, sarcoma=17, adrenal=3, esophageal=2, melanoma=3, breast=1, tcc=1). Tumors were diagnosed by biopsy, or PET avidity (median SUV max = 9.5) and interval growth. 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, for a circumferential solid or ground glass margin > 4mm. Patients were followed with contrast-enhanced CT 3-monthly until death, or local tumor progression (LTP), or for at least 12 months post procedure. LTP was defined as contiguous enlargement or a change in the shape of the ablation zone or the development of contrast enhancement in part of the zone. Survival rate was evaluated by Kaplan-Meier analysis.

Microwave ablation was technically successful in n=88 (96%) of lesions. Mean ablation duration was 4 minutes (1-22 minutes). 21(29%) pneumothoracies were diagnosed on chest x-ray after 72 ablation sessions; chest drain was required in 8 (11%) sessions. 30-day mortality rate was 0%. The mean hospital stay was 1.1 days (1-11 days). Local tumor progression was present in 6 tumors; for tumors under 4cm (n=88), LTP was identified in 3 (3%) at a median follow up of 13months. The mean diameter of lesions with LTP were significantly larger than those without (mean diameter 41mm vs 17mm; p=0.009). The cancer-specific survival was 79% (95%CI 0.68-0.9) at 1 year, and 66% (95% CI 0.51-0.83) at 2-years.

Microwave ablation of pulmonary malignancies is a safe, successful technique. Local control rates and survival analysis are encouraging, with rapid treatment times

Primary and metastatic lung tumors are extremely common; surgical options are often limited due to advanced disease and or poor respiratory function. Microwave ablation offers a robust method of local disease control

Little, M, Chung, D, McCarthy, E, Briggs, J, Boardman, P, Gleeson, F, Anderson, E, Percutaneous Microwave Ablation of Pulmonary Malignancies: Survival, Imaging Follow-up, and Complications.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003514.html