title: Are new criteria for mixed histology necessary for endoscopic resection in early gastric cancer?
abstract: OBJECTIVE
  Early gastric cancer (EGC) of mixed histology is more aggressive than other histologies. In addition, signet ring cell (SRC) mixed histology shows more submucosal invasion and greater lymph node metastasis (LNM). However, there are no criteria for endoscopic resection (ER) in mixed histology. Therefore, this study investigated whether new criteria for mixed histology are necessary for ER in EGC.
  
  
  METHODS
  From January 2005 to December 2012, 3419 patients with EGC underwent surgery. Lesions were classified using three histological classifications: the Japanese classification; World Health Organization (WHO) classification including SRC mixed histology; and Lauren classification. The mixed type in the Lauren classification was also reclassified according to the proportion of differentiated and undifferentiated components. Clinicopathological characteristics were compared according to histological classifications, with special reference to the ER criteria.
  
  
  RESULTS
  With the Lauren classification, 179 (5.3%) lesions were classified as mixed type, including 54 (30.2%) lesions as the differentiated-predominant mixed type. There were 361 (10.6%) lesions classified as SRC mixed histology. Mixed-type lesions in the Lauren classification and SRC mixed lesions were significantly associated with larger size and a greater LNM. Among the lesions meeting the ER criteria, 20 (1.6%) and 55 (4.7%) were categorized as mixed type by the Lauren classification and SRC mixed histology, respectively. However, there was no LNM among the lesions recategorized into mixed histology.
  
  
  CONCLUSIONS
  Mixed histology showed no LNM among the lesions met the present ER criteria. Thus, separate criteria for mixed histology might be not necessary in the criteria for ER in EGC.
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Hong Jin
authors.initials: HJ
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Yong Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. Electronic address: otilia94@yuhs.ac.
authors.forename: Jie-Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: HyunKi
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Hoguen
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jae Jun
authors.initials: JJ
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Youn
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Hyojin
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Hyung
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Noh
authors.affiliation: Department of Surgery, Yonsei University College of Medicine, Seoul, South Korea; Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Seung Ho
authors.initials: SH
authors.lastname: Choi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018279:Carcinoma, Signet Ring Cell / Q000473:pathology* / Q000601:surgery; D055088:Early Detection of Cancer; D005260:Female; D005743:Gastrectomy; D005773:Gastroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery
keywords: Early gastric cancer; Endoscopic resection; Lymph node metastasis; Mixed histology