title: Endoscopy/EUS-guided fiducial marker placement in patients with esophageal cancer: a comparative analysis of 3 types of markers.
abstract: BACKGROUND
  Markers placed at the borders of esophageal tumors are potentially useful to facilitate radiotherapy (RT) target delineation, which offers the possibility of image-guided RT.
  
  
  OBJECTIVE
  To 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.
  
  
  METHODS
  Prospective, single-center, feasibility and comparative study.
  
  
  METHODS
  Tertiary-care medical center.
  
  
  METHODS
  Thirty patients with esophageal cancer who were referred for RT.
  
  
  METHODS
  Patients 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.
  
  
  METHODS
  Technical feasibility, technical benefit, and adverse events of 3 types of markers.
  
  
  RESULTS
  A 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.
  
  
  CONCLUSIONS
  Single-center, nonrandomized design.
  
  
  CONCLUSIONS
  Endoscopy/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. (
  
  
  BACKGROUND
  NTR4724.).
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Melanie
authors.initials: M
authors.lastname: Machiels
authors.affiliation: Department of Gastroenterology & Hepatology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Jeanin
authors.initials: J
authors.lastname: van Hooft
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Peng
authors.initials: P
authors.lastname: Jin
authors.affiliation: Department of Surgery, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Mark I
authors.initials: MI
authors.lastname: van Berge Henegouwen
authors.affiliation: Department of Oncology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Hanneke M
authors.initials: HM
authors.lastname: van Laarhoven
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Tanja
authors.initials: T
authors.lastname: Alderliesten
authors.affiliation: Department of Radiation Oncology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Maarten C
authors.initials: MC
authors.lastname: Hulshof
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D019160:Endosonography / Q000379:methods*; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D004945:Esophagoscopy / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018084:Ultrasonography, Interventional / Q000379:methods*