Endoscopy/EUS-guided fiducial marker placement in patients with esophageal cancer: a comparative analysis of 3 types of markers

BackgroundMarkers placed at the borders of esophageal tumors are potentially useful to facilitate radiotherapy (RT) target delineation, which offers the possibility of image-guided RT.ObjectiveTo evaluate and compare the feasibility and technical benefit of endoscopy/EUS-guided marker placement of 3 different types of markers in patients with esophageal cancer referred for RT.DesignProspective, single-center, feasibility and comparative study.SettingTertiary-care medical center.PatientsThirty patients with esophageal cancer who were referred for RT.InterventionsPatients underwent endoscopy/EUS-guided implantation of 1 type of marker. A solid gold marker (SM) with fixed dimensions, a flexible coil-shaped gold marker (FM) with hand-cut length (2-10 mm), and a radiopaque hydrogel marker (HG) were used. Technical feasibility and adverse events were registered. CT scans and cone-beam CT scans (CBCT) acquired during RT were analyzed to determine and compare the visibility and continuous clear visibility of the implanted markers.Main Outcome MeasurementsTechnical feasibility, technical benefit, and adverse events of 3 types of markers.ResultsA total of 101 markers were placed in 30 patients. Implantation was technically feasible in all patients without grade 3 to 4 adverse events. Two patients with asymptomatic mediastinitis and one with asymptomatic pneumothorax were seen. Visibility on CT scan of all 3 types of implanted markers was adequate for target delineation. Eighty percent of FMs remained continuously visible over the treatment period on CBCT, significantly better than SMs (63%) and HGs (11%) (P = .015). When we selected FMs ≥5 mm, 90.5% remained visible on CBCT between implantation and the end of RT.LimitationsSingle-center, nonrandomized design.ConclusionEndoscopy/EUS-guided fiducial marker placement for esophageal cancer is both safe and feasible and can be used for target volume delineation purposes on CT. Our results imply a significant advantage of FMs over SMs and HGs, regarding visibility and continuous clear visibility over the treatment period. (Clinical trial registration number: NTR4724.)