A prospective trial of CT-guided percutaneous microwave ablation for lung tumors

Background: Percutaneous ablation is an alternative treatment for lung cancer in non-operable patients. This is a prospective clinical trial for percutaneous microwave ablation (pMWA) of biopsy-proven lung cancer to demonstrate safety and efficacy. Methods: A prospective trial from 6-1-2016 to 1-1-2019 enrolled patients with biopsy-proven primary or metastatic lung cancer <3 cm in size and 1 cm away from the pleura for pMWA with the Emprint Ablation System with Thermosphere Technology for Phase I analysis, (Clinicaltrials.gov; #NCT0267302). Patients were followed for 1 year with PET/CT and PET/MR to determine patterns of recurrence and efficacy of ablation. Results: After 12 patients consented for biopsy, 6 patients underwent treatment of 7 lesions, 3/6 women, median age of 67 (IQR, 65-70) years, body mass index (BMI): 27.8 (IQR, 21.4-32.1) kg/m2, lesion distance to pleura 24.4 (IQR, 13-38) mm, lesion size of 10.7 (IQR, 6-14) mm, and ablation duration time 5.9 (IQR, 3-10) minutes. pMWA were completed at 75 W. Twelve adverse events were reported (1 Grade 3, 3 Grade 2, and 8 Grade 1 events) with Grade 4 or 5 events. Mean % change after ablation in forced expiratory volume in one second (FEV1) was -2% and diffusion capacity for carbon monoxide (DLCO) was -1%. After 2-3 months, the lesions would decrease in size, rim thickness, fluorodeoxyglucose (FDG) activity, and T2 signal. FDG activity after 6 months was below blood pool in all cases. The ablation zones stabilized by 6-12 months. One patient expired during the study from pneumonia unrelated to ablation without local recurrence. Of the seven ablations during the 1 year follow-up, there was local tumor recurrence at 271 days following ablation at the apex of the ablation zone, subsequently successfully treated with percutaneous cryoablation (Cryo). Conclusions: pMWA appears to be a safe and effective mechanism for treatment of primary and secondary tumors of the lung, with possible preservation of pulmonary function.