Fiducial marker placement for stereotactic body radiation therapy via convex probe endobronchial ultrasound: a case series and review of literature

Abstract

Convex probe endobronchial ultrasound (CP-EBUS) and stereotactic body radiotherapy (SBRT) are valuable tools in the diagnosis, staging, and treatment of thoracic malignancies. With widespread clinical adoption, novel uses of CP-EBUS beyond mediastinal diagnosis and staging continue to be discovered. SBRT is an attractive treatment strategy in early-stage lung cancer and oligo-metastatic disease of the chest when a surgical approach is either not feasible or desirable. Accurate application of SBRT is aided by the placement of radio-opaque fiducial markers (FM) to compensate for respiratory cycle movements. We describe eight patients with central thoracic lesions, either known or suspected to be malignant, who underwent EBUS bronchoscopy with lesion sampling and successful intralesional placement of modified FM via our technique, review the existing literature on this topic, and discuss the nuances of coding and billing aspects of FM placement.

Long term safety and visibility of a novel liquid fiducial marker for use in image guided radiotherapy of non-small cell lung cancer

“…An advantage of the liquid fiducial marker is that it can be injected with standard endoscopic (EUS/EBUS) equipment with 22–25 gauge needles compared to the 18–19 gauge needles used for placement of most solid metal fiducial markers [6] , [11] . The liquid formulation also allows for the placement of several markers in one session without needing to “reload” the endoscopy needle between each implantation as is most often the case with solid metal markers [24] . The size of the liquid fiducial marker can be customised by varying the injected volume.…”

Role of Convex Probe Endobronchial Ultrasound in the Diagnosis and Treatment of Nonmalignant Diseases

“…CP-EBUS is reportedly used for the placement of fiducial markers for tracking purposes in patients requiring stereotactic radiation therapy and CyberKnife therapy for mediastinal and lung cancers [53, 54]. Harley et al successfully used CP-EBUS for the placement of 2–5 fiducial markers around tumor masses in 43 patients scheduled for radiosurgery [55].…”

Fiducial markers for stereotactic lung radiation therapy: review of the transthoracic, endovascular and endobronchial approaches

“…In 2016, we described the safe insertion of a linear gold FM in a hilar lymph node by a transbronchial needle guided by L-EBUS [47]. Since then, case series have been described [48]. This approach requires deep sedation, specific equipment, an experienced operator and, furthermore, by crossing the bronchial wall for FM insertion into lymph nodes, this technique exposes the area to rare iatrogenic mediastinal infections [49].…”