Endovascular pulmonary arterial fiducial marker placement for particle radiotherapy using proton or carbon-ion beams for lung cancer.

This study evaluated the safety, feasibility and efficacy of endovascular pulmonary arterial fiducial marker (EVFM) placement for image-guided particle therapy using proton or carbon-ion beams in patients with primary or metastatic lung cancer. Methods: A 5F catheter system was used to insert platinum coil markers via the right femoral vein into a distal pulmonary artery near the tumor under fluoroscopic guidance. Tumor-to-marker distances, marker migration and therapy completion were assessed. From July 2016 to January 2019, 54 patients (38 men, 16 women; median age, 71 years) with 46 primary and 8 metastatic lung tumors underwent marker placement. Tumors were located in 33 right and 21 left lobes, with a median diameter of 22 mm. Ten patients received proton therapy, and 44 received carbon-ion therapy. There were no marker placement related complications. Transient arrhythmias occurred only when the guide wire passed through the right ventricle. Tumor-to-marker distances ranged from 0-17 mm (median, 5 mm). Migration during irradiation was minimal (median, 0 mm); one case showed a 4-mm shift due to lung deformation, not marker displacement. All patients completed scheduled therapy without marker migration. EVFM placement is a feasible and safe alternative to computed tomography- or bronchoscopy-guided fiducial marker placement, offering accurate localization with minimal complications or marker migration in particle therapy for lung cancer.