Christiane Weigel

Laser Ablation of Metastatic Lesions of the Lung: Long-Term Outcome

OBJECTIVE Pulmonary metastatic lesions are present in 20-54% of all patients who die of cancer. Surgical studies have shown that local management of distant tumor metastasis as part of multimodal cancer therapy improves survival. Minimally invasive procedures such as thermal ablation are still to prove their clinical relevance. The aim of this study was to monitor therapeutic outcome and long-term results after percutaneous laser-induced thermal ablation. SUBJECTS AND METHODS Sixty-four patients with metastasis to the lung underwent laser-induced thermal ablation in an ongoing prospective study. A total of 129 percutaneous procedures were performed to manage a total of 108 lung lesions. The median tumor size was 2.0 cm (range, 0.4-8.5 cm). Adequate management of all known individual tumor correlates was critical for definitive patient therapy. The Kaplan-Meier method was used to calculate survival and recurrence rates. RESULTS Definitive management of initial pulmonary disease was achieved in 31 of 64 patients. The 1-, 2-, 3-, 4-, and 5-year survival rates after ablative therapy were 81%, 59%, 44%, 44%, and 27%. The median progression-free interval was 7.4 months. There were no therapy-related deaths. Pneumothorax occurred in 38% of the patients, necessitating periprocedural drainage in 5% of all cases. Parenchymal bleeding (13% of cases) always was self-limited. CONCLUSION Laser ablative therapy for pulmonary metastasis is a promising option in multimodal cancer therapy. The procedure is safe and effective. The initial clinical outcome data strongly suggest that this technique has the potential to improve survival among selected patients.

Laser Ablation of Lung Metastases: Technique and Results after 21 Treatments

Summary A thin-caliber applicator system was developed for laser ablation of lung metastases. Feasibility of lung metastases ablation as well as the complication rate and clinical results were evaluated. We calibrated the miniaturized applicator system in non-perfused bovine liver for maximum energy supply and necessary flow of the cooling saline solution in reference to a commercially available system (Power laser applicator kit, Somatex, Teltow, Germany). The size of heat coagulation in bovine liver was 24 ± 2 ml with the miniaturized system in comparison to a size of 29 ± 7 ml for the existing applicator. 15 W were applied for 20 min and a saline flow of 40 ml/h with the miniaturized applicator and 30 W, 20 min, 60 ml/min with the standard applicator. 21 patients with 32 lung metastases were then treated and the results as well as minor and major complications were evaluated. Ablation was technically successful in all but 2 patients. 14 patients were considered to be effectively treated. Their metastases showed a marked reduction of volume. Volume reduction took several months to develop. Successful treatment had either a ground-glass appearance of the treated site or a cystic defect as a morphological correlate. We conclude that successful ablation of lung metastases is possible with a miniaturized applicator.

Percutaneous Laser Ablation of Lung Metastases

CT guidance allows for placement of a laser applicator into a pulmonary metastasis while the patient is under conscious sedation. The metastasis may thus be thermally destroyed. We describe how a laser applicator used in pulmonary lesions is designed; how complications from laser ablation compare to diagnostic biopsies; and how the technique may supplement traditional surgical therapy. It should be mentioned that following laser ablation, lesions enlarge, and it may take weeks or months before scar formation is reached. The technique is compared with other modalities and the necessity to combine it with local pharmaceutical approaches is discussed.