Wednesday June 18 2008
106 patients were included in the trial
“Lung cancer patients with little chance of survival have been offered new hope with a treatment that targets tumours in the lungs with radiation”, reports The Daily Telegraph today. The newspaper says the new technique, called radiofrequency ablation, managed to successfully treat 88% of tumours and about 50% of patients who had primary lung cancer were alive after two years.
The story is based on a study looking at the effects of radiofrequency ablation in people with small metastatic lung tumours that could not be treated with surgery, radiotherapy or chemotherapy. The technique involves inserting a small probe into the tumour and using a radiofrequency energy to generate heat and kill the surrounding tumour tissue. The results in this “hard to treat” population are promising: the study shows that it is technically possible to use this technique for lung cancer, that a high proportion of tumours treated in this way respond for one year, and that the procedure is relatively safe. The next stage will be to carry out a randomised controlled trial to look at whether this treatment improves survival compared with non-surgical techniques.
Where did the story come from?
Dr Riccardo Lencioni and colleagues from the University of Pisa, and other universities and medical centres in Europe, Australia and the US carried out this research. The study was funded by Angiodynamics, the company that made the radiofrequency ablation device. It was published in the peer-reviewed medical journal The Lancet Oncology.
What kind of scientific study was this?
This was a prospective case series looking at the effects of radiofrequency ablation on malignant lung cancer. Radiofrequency ablation is a minimally invasive technique, which involves inserting a probe through the skin into the tumour, where it produces radiofrequency energy that heats the area around the probe to about 90°C and kills the surrounding tissue, including the tumour cells.
The researchers enrolled 106 adult patients with malignant lung tumours (confirmed by biopsy), who were not suitable for surgery and not well enough to receive chemotherapy or radiotherapy. Patients could have up to three tumours per lung, with a maximum width of 3.5cm. The tumours could include non-small cell lung cancer or metastases arising from primary cancers elsewhere in the body. Researchers used an imaging technique (computed tomography) to guide the radiofrequency probes into each target tumour, and applied radiofrequency waves until an area of tissue just larger than the area of the tumour was destroyed.
The researchers recorded whether the ablation procedure was completed successfully, whether any complications arose and whether the patients’ lung function was affected. Patients had follow-up visits at one and three months after treatment, and then every three months, for a total of two years. The patients were deemed to have complete response to treatment if their tumours had shrunk in diameter by 30%, or more, from measurements taken one month after the surgery and if there was no growth of the tumour at the ablation site for at least one year after the surgery. Patient survival and quality of life were also recorded.
What were the results of the study?
The researchers managed to correctly insert the probe and complete the ablation procedure in 105 of the 106 patients. In all, these patients needed 137 ablation procedures between them. In about one fifth of these procedures there was a major complication, most commonly involving air in the chest cavity, which needed draining, with a few cases of abnormal leakage of fluid into the chest cavity, which also required draining. No patient died as a result of the procedure or these complications. The patients’ lung function was not significantly affected by the procedure.
Of the 85 patients followed up for a year, 75 showed a complete response (88%). During the two years of follow-up, 20 patients died from tumour progression (about 19%) and 13 died from other causes (about 12%). Overall survival varied between patients with different diagnoses. At one year, 70% of patients with non-small cell lung cancer survived, 89% of patients with lung metastases from colorectal cancer survived and 92% of patients with lung metastases from other sites survived. At two years, survival in these groups was 48%, 66% and 64% respectively.
What interpretations did the researchers draw from these results?
The researchers concluded that radiofrequency ablation can produce a high level of sustained complete response in appropriately selected patients with lung malignancies or metastases. They suggest that randomised controlled trials comparing this procedure with accepted non-surgical techniques should be carried out.
What does the NHS Knowledge Service make of this study?
This was a well-designed study, which has shown that the treatment of lung malignancies and metastases with radiofrequency ablation is feasible, produces good response rates and is sufficiently safe to warrant further study.
This study was not designed to show that the procedure improved survival. Randomised controlled trials will be needed to determine whether it is superior to other techniques. It is worth noting that this technique will not be suitable for treating all lung metastases, as tumours have to be below a certain size for it to be effective.