title: Clinical significance and validity of the subclassification for colorectal laterally spreading tumor granular type.
abstract: OBJECTIVE
  Colorectal laterally spreading tumor granular type (LST-G) is generally divided into two subtypes based on morphology. Here, we retrospectively investigated the clinical significance of a concrete, objective LST-G subclassification.
  
  
  METHODS
  This study examined 636 consecutive cases that were resected endoscopically or surgically. LST-G was subclassified as follows: Type 1, a lesion with homogenous uniform granules with uniform (<5 mm) nodules; Type 2, a lesion with granules and small nodules (≥5 mm, <10 mm); or Type 3, a lesion accompanied by large nodules (≥10 mm). For the validation study, 194 images were compiled from 97 cases investigated using conventional colonoscopy and chromoendoscopy with indigo carmine dye spraying. Images were distributed in a randomized order to students without prior endoscopy experience, less-experienced endoscopists (LEE group), and highly experienced endoscopists (HEE group). Diagnostic accuracy and interobserver agreement were then evaluated.
  
  
  RESULTS
  There was no submucosal invasion in Type 1 lesions. The incidence of deep submucosal invasive carcinoma was higher for Type 3 lesions than for Type 2 lesions. Interobserver agreement was good in each group. Diagnostic accuracy was higher in the HEE group than in the student and LEE groups. Chromoendoscopy had a higher accuracy rate than conventional colonoscopy in the LEE and HEE groups (LEE, 0.74 vs 0.69, P < 0.05; HEE, 0.84 vs 0.78, P < 0.05).
  
  
  CONCLUSIONS
  This subclassification of LST-G according to the diameters of granules and nodules was both useful for choosing therapeutic strategies in the clinical setting and universally applicable.
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Shigita
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Oka
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Kyoku
authors.initials: K
authors.lastname: Sumimoto
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Hirano
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Tamaru
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ninomiya
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Asayama
authors.affiliation: Department of Endoscopy, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Hayashi
authors.affiliation: Department of Anatomical Pathology, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Nagata
authors.affiliation: Department of Endoscopy, Hiroshima City Asa Hospital, Hiroshima, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Arihiro
authors.affiliation: Departments of Gastroenterology and Metabolism, Hiroshima University Hospital, Hiroshima, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Chayama
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000473:pathology* / Q000601:surgery; D000236:Adenoma / Q000145:classification / Q000473:pathology* / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D004396:Coloring Agents; D003594:Cytoplasmic Granules / Q000473:pathology*; D005260:Female; D006801:Humans; D007203:Indigo Carmine; D007564:Japan; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D009626:Terminology as Topic
chemical_list: D004396:Coloring Agents; D007203:Indigo Carmine
keywords: LST granular type; diagnostic accuracy; kappa value; size of nodule; subclassification