title: Probe-based confocal laser endomicroscopy in the margin delineation of early gastric cancer for endoscopic submucosal dissection.
abstract: OBJECTIVE
  We evaluated probe-based confocal laser endomicroscopy (pCLE) in the margin delineation of early gastric cancer (EGC) for endoscopic submucosal dissection in comparison with white-light imaging with chromoendoscopy (CE).
  
  
  METHODS
  We conducted a prospective, randomized controlled study from November 2013 to October 2014 in a tertiary referral hospital. A total of 101 patients scheduled for endoscopic submucosal dissection due to differentiated EGC were randomized into pCLE and CE groups (pCLE 51, CE 50). Markings were made by electrocautery at the proximal and distal tumor margins, as determined by either pCLE or CE. The distance from the marking to the tumor margin was measured in the resected specimen histopathologically and was compared between the two groups by a linear mixed model.
  
  
  RESULTS
  Among 104 lesions, 80 lesions with 149 markings (pCLE 68, CE 81) were analyzed after excluding undifferentiated EGCs (n = 8) and unidentifiable markings (n = 13). Although the complete resection rate showed no difference between the groups (94.6% vs 93.2%, P = 1.000), the median distance from the marking to the margin was shorter in the pCLE group (1.3 vs 1.8 mm, P = 0.525) and the proportion of the distance <1 mm was higher (43.9% vs 27.6%, P = 0.023) in the pCLE group. Finally, subgroup analysis with superficial flat lesions (18 lesions, 31 marking dots) showed a significantly decreased distance in the pCLE group (0.5 vs 3.1 mm, P = 0.007).
  
  
  CONCLUSIONS
  Among EGCs with superficial flat morphology, in which the accurate evaluation of lateral extent is difficult with CE, pCLE would be useful for more precise margin delineation.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Jun Chul
authors.initials: JC
authors.lastname: Park
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Yehyun
authors.initials: Y
authors.lastname: Park
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Ki
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jeong-Hyeon
authors.initials: JH
authors.lastname: Jo
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Chan Hyuk
authors.initials: CH
authors.lastname: Park
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Eun Hye
authors.initials: EH
authors.lastname: Kim
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Da Hyun
authors.initials: DH
authors.lastname: Jung
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Chung
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Sung Kwan
authors.initials: SK
authors.lastname: Shin
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Sang Kil
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Yonsei Institute of Gastroenterology, Seoul, Korea.
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005753:Gastric Mucosa / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D005773:Gastroscopy / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008297:Male; D000072662:Margins of Excision; D018613:Microscopy, Confocal; D008875:Middle Aged; D011446:Prospective Studies; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*
keywords: early gastric cancer; endoscopic submucosal dissection; probe-based confocal laser endomicroscopy