Prospective Evaluation of Lung Cancer Ablation Called Promis

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Prospective Evaluation of Lung Cancer Ablation Called Promising

By Crystal Phend, Staff Writer, MedPage Today

Published: June 18, 2008

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston. Earn CME/CE credit

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PISA, Italy, June 18 -- Radiofrequency ablation of small lung tumors may yield outcomes that rival standard radiation for selected patients ineligible for surgery or other therapy, researchers found in a seven-center trial in Europe, the U.S., and Australia.

In the first large prospective study of the procedure, there were no procedure-related deaths or any significant worsening of pulmonary function and "acceptable morbidity," reported Riccardo Lencioni, of Cisanello University Hospital here, and international colleagues online in the The Lancet Oncology.

Two-year survival in the RAPTURE study was 48% for patients with non-small-cell lung cancer and up to 92% for cancer-specific survival among patients with early-stage disease. Action Points

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Explain to interested patients that the study included patients who were not candidates for other standard therapies for lung cancer, which makes it difficult to compare efficacy and safety between treatments.

Although reliable comparison with other treatments was not possible because of the trial's severely impaired patient population unsuited to conventional treatment, the researchers noted that the early-stage survival results were particularly promising.

"This percentage compares well with reported outcomes of external-beam or stereotactic radiotherapy in this patient population," they wrote.

These findings provide long-awaited confirmation of radiologists' experience with radiofrequency ablation of lung tumors, commented Christos Georgiades, M.D., Ph.D., of Johns Hopkins, in an interview.

"The results are quite promising," he said, and added that the safety results were not surprising. "It just proves that in the hands of experienced interventionalists this is a very safe procedure even in … very ill patients."

Retrospective studies have shown procedure-specific mortality rates of 2.7% with experienced operators but were expected to have fallen to less than 1% over the past several years.

However, the field was caught in a grey zone without a solid prospective randomized trial to confirm safety and efficacy.

Because of this, the FDA issued a cautionary notice late last year about deaths caused by radiofrequency ablation of lung tumors. (See: Radiologists Take FDA Warning on Lung Ablation in Stride)

Although many radiofrequency ablation devices have been cleared for soft tissue, including non-resectable liver lesions and palliation of painful metastatic bone lesions, none has been cleared for lung-tumor ablation specifically.

Although RAPTURE provides key support for the procedure, the next step is randomized controlled trials comparing radiofrequency ablation with standard non-surgical treatment options, Dr. Lencioni's group said.

Surgical resection is the best option for eligible patients, which offers the highest chance for cure, Dr. Georgiades said.

However, many patients need non-surgical options because comorbidities, the extent and location of lesions in the lungs, and associated extrapulmonary disease often make patients ineligible for resection.

"Moreover, the high risk of recurrence and the need to remove functioning lung tissue along with the lesions restricts indications for surgery," the researchers said.

Their prospective, single-arm, multicenter trial included 106 adults with biopsy-proven NSCLC or lung metastasis who were rejected for surgery and considered unfit for radiotherapy or chemotherapy. Participants could have up to three tumors per lung, but each had to be 3.5 cm or smaller in diameter and at least 1 cm from critical structures.

For the 183 malignant lung tumors treated in the study, the median size was 1.5 cm. The most common diagnosis was metastasis from colorectal adenocarcinoma (53 patients), followed by NSCLC (33 patients), and metastasis from other malignancies (20 patients).

Radiofrequency ablation was a technical success for 99% of patients. One patient with a single colorectal metastasis could not be treated because the radiologists could not place the ablation device inside the patient's small tumor.

Major complications included large or symptomatic pneumothorax needing drainage in 27 of 137 procedures, for which five patients needed catheter drainage for more than a day, and pleural effusion needing drainage in four cases. Minor complications included pneumothorax (28) or pleural effusion (11) not needing treatment and self-limiting intrapulmonary hemorrhage (3).

Pulmonary function tests showed slight declines among patients with NSCLC likely because of progressive underlying lung disease but no significant decrease in this or other patient subgroups.

Most patients imaged on CT had a confirmed complete response of all treated lesions for at least a year after treatment (88%), while the rest had incomplete ablation with evidence of local progression.

Survival rates were:

Among patients with NSCLC, 70% overall survival at one year and 48% at two years.

Among patients with colorectal metastases, 89% overall survival at one year and 66% at two years.

Among patients with non-colorectal metastases, 92% overall survival at one year and 64% at two years.

Cancer-specific survival of 92% at one year and 73% at two years in patients with NSCLC.

Cancer-specific survival of 91% at one year and 68% at two years in patients with colorectal metastases.

Cancer-specific survival of 93% at one year and 67% at two years in patients with non-colorectal metastases.

Among patients with stage I NSCLC, 75% two-year overall survival and 92% two-year cancer-specific survival.

The researchers noted that the follow-up period may not have been long enough to detect late tumor recurrences. Other limitations were the heterogeneous patient population that included those with NSCLC and metastases from different primary malignancies and that the study was not designed to measure survival benefits.

"A randomized controlled trial comparing radiofrequency ablation versus standard treatment options is now warranted to prove the clinical benefit of this approach," Dr. Lencioni and colleagues concluded.Lencioni's

The study was funded by Angiodynamics. The researchers declared no conflicts of interest.

Dr. Georgiades reported having been a consultant for Boston Scientific.

Primary source: The Lancet Oncology

Source reference:

Lencioni R, et al "Response to radiofrequency ablation of pulmonary tumours: a prospective, intention-to-treat, multicentre clinical trial (the RAPTURE study)" Lancet Oncol 2008.

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