Multiple-electrode switching radiofrequency ablation may successfully treat lung tumors

1. Radiofrequency ablation with a multiple-electrode switching system can safely be used to successfully treat lung tumors 2-5 cm in size in nonsurgical candidates.

Evidence Rating Level: 4 (Below-Average)

Study Rundown: Patients with non-surgical lung tumors face limited treatment options, many of which are often accompanied by a high risk of morbidity and mortality. Radiofrequency ablation (RFA) has been shown to be effective in decreasing the size of small lung tumors, but has not been as successful in the treatment of larger tumors, with increased rates of local recurrence as compared to other modalities. Multiple-electrode switching RFA systems can increase the overall ablative zone volume through sequential switching of power between electrodes, which would be particularly useful in larger tumors. The current study is a phase II clinical trial demonstrating that RFA using a multiple-electrode switching system can be a safe alternative treatment for non-surgical lung tumors with low recurrence rates and morbidity similar to that of standard RFA systems. Using between 2 and 3 RF electrode arrays, technical success was achieved in all patients, while 1-year tumor progression rates were 12.7%. Significant complications occurred in 12% of patients, including pleuritis, pneumothorax and pulmonary hemorrhage, though no procedure-related deaths occurred. This study provides evidence of a safe, new treatment for non-surgical lung tumor patients, increasing the viable options for such patients. The relatively small size and lack of patient-controls are the most significant limitations, in addition to the relatively short follow-up period of only 1 year. Future studies should examine this technique in a larger population, and may benefit from randomized controlled trial design to compare multiple-electrode switching RFA systems to other treatment modalities, such as body radiation therapy, or pulmonary resection.

Click to read the study in American Journal of Roentgenology

Relevant reading: Lung radiofrequency ablation for the treatment of unresectable recurrent non-small-cell lung cancer after surgical intervention.

In-Depth [case series]: A total of 33 patients (78% male with mean age 70.5 ± 10 years) from a single medical center with nonsurgical lung tumors sized 2.0 – 5.0 cm were included in the trial. These patients were not matched to controls. All patients had fewer than 3 tumors, with a total of 51 treated tumors, 35 of which were treated with multiple electrode switching RFA. These 35 tumors were evaluated for size, response to treatment, adverse events, and recurrence. Among these 35 tumors, the mean diameter was 3.0 cm +/- 0.7 (range, 2-4.4 cm.) Tumors were primarily non-small cell lung cancer (51%), while the remainder were metastases (49%). There were no deaths or grade 4 adverse events at the time of procedure, though 12% of patients had grade 3 adverse events including pulmonary hemorrhage, pneumothorax and aseptic pleuritis, and 39% experienced grade 2 adverse events including minor pneumothorax or pneumonitis. Overall, the rate of one-year local tumor progression was 12.7% (95% CI: 1.0-25.5) with a one-year survival rate of 81.2% (95% CI: 67.6-94.8). The survival rate was insignificantly higher in those primary lung cancer than in those with metastatic lung cancer, at 82.4% versus 79.4% (p = 0.25), though univariate analysis revealed that prognoses were poorer with tumors larger than 3.0 cm (p = 0.04) and if extrapulmonary tumors were present (p = 0.03).

Image: PD

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