Radiofrequency Ablation Offers Promise in Treatment of Lung Cancer

Roxanne Nelson

June 19, 2008

June 19, 2008 — Treatment options are limited for patients with non-small-cell lung cancer (NSCLC) who are not surgical candidates, and surgery is frequently not feasible for patients with secondary lung malignancies. However, according to new data published online June 17 in the Lancet Oncology, radiofrequency ablation could be an option for patients who are unable to undergo surgery, radiotherapy, or chemotherapy.

Percutaneous radiofrequency ablation is a relatively new and minimally invasive technique that has been used to treat solid tumors. In particular, it is becoming a viable option for unresectable liver malignancies. Although the use of radiofrequency ablation is at an early stage of clinical application for other types of solid tumors, recent studies have shown that it has potential in the treatment of lung, bone, and renal malignancies. The authors note that several single-institution case series have suggested that radio frequency ablation is a feasible option for patients with unresectable or medically inoperable pulmonary tumors.

In this study, Riccardo Lencioni, MD, associate professor of radiology in the department of oncology, transplants and advanced technologies in medicine at the University of Pisa, in Italy, and colleagues designed a prospective single-group multicenter clinical trial to evaluate the feasibility, safety, and effectiveness of percutaneous computed tomography (CT)-guided radiofrequency ablation in the treatment of NSCLC. The study also included patients with metastatic disease to the lungs.

A series of 106 patients, with a total 183 lung tumors measuring 3.5 cm or smaller in diameter, were enrolled in the study. Of this group, 33 patients had been diagnosed with NSCLC, 53 had metastasis from colorectal carcinoma, and 20 patients had metastasis from other primary malignancies. All of the patients were deemed unsuitable for surgery, radiotherapy, or chemotherapy.

The primary end points were technical success, safety, and confirmed complete response of tumors. The authors defined technical success as the correct placement of the ablation device in all target tumors with completion of the planned ablation protocol. Secondary end points of the study included overall survival, cancer-specific survival, and quality of life.

Study participants underwent radio frequency ablation in accordance with standard rules for CT-guided lung biopsy. Follow-up visits were scheduled at 1 and 3 months after the procedure, and then at 3-month intervals for up to 2 years.

A total of 137 procedures were performed, and treatment was successfully completed in 105 of 106 patients (99%). From this group, it was possible to assess the primary end point of a confirmed complete response in 85 patients (80%). The researchers noted a confirmed complete response of all targeted tumors that lasted for at least 1 year after treatment in 75 of 85 patients (88%), with incomplete ablation and evidence of local progression in at least 1 treated tumor in the remaining patients. There was no difference in tumor responses to ablation between patients with NSCLC and those with metastatic lung disease.

Overall and Cancer-Specific Survival

Patient Subgroup Overall Survival at 1 Year Overall Survival at 2 Years Cancer-Specific Survival at 1 Year Cancer-Specific Survival at 2 Years
NSCLC 70% 48% 92% 73%
Stage 1 NSCLC n/a 75% n/a 92%
Colorectal metastases 89% 66% 91% 68%
Metastases from other sites 92% 64% 93% 67%

Although there was no procedure-related mortality, 27 of the procedures were complicated by a large or symptomatic pneumothorax that required drainage. A second major complication was the occurrence of pleural effusion in 4 procedures, which also necessitated drainage.

"Our study shows that percutaneous CT-guided radio frequency ablation yields high proportions of sustained [complete responses] in properly selected patients with primary or secondary lung malignancies, and is associated with acceptable morbidity," write the authors.

They note that the rate of overall survival was greatly affected by the recruitment of patients with severely impaired pulmonary function, with substantial comorbidities, or both. All participants were deemed unsuitable for surgery, radiotherapy, or chemotherapy, or they had exhausted conventional treatment options. Under these circumstances, it was not possible to reliably compare radio frequency ablation survival curves and those achieved with other treatments.

"Additionally, the patient population was heterogeneous and included patients with NSCLC and patients with pulmonary metastases from different primary malignancies, and the study was not designed to provide evidence of survival benefits," they write. "A randomized controlled trial comparing radio frequency ablation versus standard treatment options is now warranted to prove the clinical benefit of this approach."

This study was supported by AngioDynamics. The authors have disclosed no relevant financial relationships.

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