Percutaneous Radiofrequency Ablation Shows Promise In The Treatment Of Lung Tumours

Main Category: Lung Cancer
Also Included In: Cancer / Oncology
Article Date: 01 Jul 2008 - 3:00 PDT

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Percutaneous radiofrequency ablation - a minimally invasive treatment technique that heats and destroys cancer cells - achieves a high rate of sustained complete responses in selected patients with lung tumours, according to results from the first prospective study of patients treated with technique.

Tumours in the lungs are common. Lung cancer is the leading cause of cancer death in both men and women. Surgical resection is the standard of care for early stage non-small cell lung cancer, which is the commonest type of lung cancer. It achieves five-year survival rates greater than 50%. Patients with this type of cancer but who are unfit for surgery may be treated with radiotherapy, with five-year survival rates of up to 27%.

The lungs are also the second most frequent site of metastatic disease, in which cancer cells spread from the primary tumour. Surgical resection of pulmonary metastates has been shown to improve survival in selected patients. However, only a few patients can undergo resection because of the extent and locations of tumours in the lungs, tumours elsewhere in the body or concurrent medical conditions. The high risk of cancer recurrence and the need to remove functioning lung tissue together with the cancerous tissue further restricts the use of surgery for lung cancers, so new treatment techniques are needed.

Percutaneous radiofrequency ablation uses imaging techniques such as ultrasound or computed tomography (CT) to guide a needle electrode into a tumour. High-frequency electrical currents are then passed through the electrode, generating heat that destroys the abnormal cells.

Researchers in Europe, the USA and Australia assessed the effects of percutaneous radiofrequency ablation in a series of 106 patients with 183 small lung tumours (the average number of tumours per patient was 1.7 and tumours had a diameter of 3.5cm or less). The tumours included non-small-cell lung cancers in 33 patients, metastases from colorectal carcinoma in 53 people and metastases from other types of cancers in 20 patients. All of the patients were considered by their doctors to be unsuitable for surgery, radiotherapy or chemotherapy.

The patients were treated with radiofrequency ablation and followed up for two years. A needle was placed into each patient's tumours, guided by computed tomography (CT), and connected to a radiofrequency generator. Correct placement of the ablation device into the target tumour was achieved in 105 of the 106 patients. In the one patient who was not treated, the device could not be placed inside a small tumour.

Results showed a complete response in target tumours lasting at least one year was achieved in 75 of the 85 assessable patients (88%). Overall survival was 70% (95% confidence interval 51-83%) at one year and 48% (30-65%) at two years in patients with non-small cell lung cancer. Cancer-specific survival (the proportion of people who did not die due to cancer) was higher - 92% at one year and 73% at two years, meaning that most people who died during the study died due to causes other than cancer.

Survival was similar in the patients with colorectal metastases (89% at one year and 66% at two years) and in those with other metastases (92% at one year and 73% at two years). Cancer specific survival at two years was 68% and 67% for these two groups, respectively.

The safety profile of the procedure was considered acceptable, with no deaths or life-threatening complications associated with radiofrequency ablation. The major complications included pneumothorax (in which air escapes from the lungs into the pleural cavity) in 27 patients and pleural effusion (fluid in the space around the lungs) needing drainage in four patients. None of the patients suffered significant worsening of lung function and there were no deaths related to the procedure in any of the 137 ablation treatments performed.

The researchers, led by Dr Riccardo Lencioni, Associate Professor of Radiology in the Division of Diagnostic and Interventional Radiology at the University of Pisa, Italy, said: "Percutaneous radiofrequency ablation yields high proportions of sustained complete responses in properly selected patients with pulmonary malignancies and is associated with acceptable morbidity." They commented that the 92% two-year cancer-specific survival achieved in patients with stage I non-small cell lung cancer was promising, and comparable with the rate achieved with radiotherapy. They concluded: "A randomised controlled trial comparing radiofrequency ablation with standard non-surgical treatment options is now warranted to prove the clinical benefit of this approach."

Reference

Lencioni, R, Crocetti, L, Cioni, R et al. Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study). Lancet Oncology, published online June 18, 2008 DOI:10.1016/S1470-2045(08)70155-4

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