Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study).

BACKGROUND: Radiofrequency ablation is an accepted treatment for non-surgical patients with liver cancer. The purpose of this study was to identify the feasibility, safety, and effectiveness of percutaneous radiofrequency ablation of malignant lung tumours.

METHODS: Between July 1, 2001, and Dec 10, 2005, a series of 106 patients with 183 lung tumours that were 3.5 cm in diameter or smaller (mean 1.7 cm [SD 1.3]) were enrolled in a prospective, intention-to-treat, single-arm, multicentre clinical trial from seven centres in Europe, the USA, and Australia. Proof of malignancy was obtained by biopsy in all patients. Diagnoses included non-small-cell lung cancer (NSCLC) in 33 patients, metastasis from colorectal carcinoma in 53 patients, and metastasis from other primary malignancies in 20 patients. All patients were considered by the treating physician to be unsuitable for surgery and unfit for radiotherapy or chemotherapy. Patients underwent radiofrequency ablation in accordance with standard rules for CT-guided lung biopsy and were then followed for up to 2 years. Primary endpoints were technical success (defined as correct placement of the ablation device into all tumour targets with completion of the planned ablation protocol), safety (including identification of treatment-related complications and changes in pulmonary function), and confirmed complete response of tumours (according to modified Response Evaluation Criteria in Solid Tumors). Secondary endpoints were overall survival, cancer-specific survival, and quality of life. This trial is registered with ClinicalTrials.gov, number NCT00690703.

FINDINGS: Correct placement of the ablation device into the target tumour with completion of the planned treatment protocol was feasible in 105 (99%) of 106 patients. The technical failure in one patient was caused by the inability to place the device inside a small tumour. No procedure-related deaths occurred in any of the 137 ablation procedures. Major complications consisted of pneumothorax (n=27) or pleural effusion (n=4), which needed drainage. No significant worsening of pulmonary function was noted. A confirmed complete response of target tumours lasting at least 1 year was shown in 75 (88%) of 85 assessable patients. No differences in response were noted between patients with NSCLC or lung metastases. Overall survival was 70% (95% CI 51-83%) at 1 year and 48% (30-65%) at 2 years in patients with NSCLC, 89% (76-95%) at 1 year and 66% (53-79%) at 2 years in patients with colorectal metastases, and 92% (65-99%) at 1 year and 64% (43-82%) at 2 years in patients with other metastases. Cancer-specific survival was 92% (78-98%) at 1 year and 73% (54-86%) at 2 years in patients with NSCLC, 91% (78-96%) at 1 year and 68% (54-80%) at 2 years in patients with colorectal metastases, and 93% (67-99%) at 1 year and 67% (48-84%) at 2 years in patients with other metastases. Patients with stage I NSCLC (n=13) had a 2-year overall survival of 75% (45-92%) and a 2-year cancer-specific survival of 92% (66-99%).

INTERPRETATION: Percutaneous radiofrequency ablation yields high proportions of sustained complete responses in properly selected patients with pulmonary malignancies, and is associated with acceptable morbidity. Randomised controlled trials comparing radiofrequency ablation with standard non-surgical treatment options are warranted.