title: Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis.
abstract: OBJECTIVE
  Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection.
  
  
  METHODS
  Initial or additional surgery with nodal dissection was performed in 653 T1 carcinoma cases. Clinicopathological factors were retrospectively analyzed with respect to nodal metastasis. The status of the muscularis mucosae (MM grade) was defined as grade 1 (maintenance) or grade 2 (fragmentation or disappearance). The lesions were then stratified based on the risk of nodal metastasis.
  
  
  RESULTS
  Muscularis mucosae grade was associated with nodal metastasis (P = 0.026), and no patients with MM grade 1 lesions had nodal metastasis. Significant risk factors for nodal metastasis in patients with MM grade 2 lesions were attribution of women (P = 0.006), lymphovascular infiltration (P < 0.001), tumor budding (P = 0.045), and poorly differentiated adenocarcinoma or mucinous carcinoma (P = 0.007). Nodal metastasis occurred in 1.06% of lesions without any of these pathological factors, but in 10.3% and 20.1% of lesions with at least one factor in male and female patients, respectively. There was good inter-observer agreement for MM grade evaluation, with a kappa value of 0.67.
  
  
  CONCLUSIONS
  Stratification using MM grade, pathological factors, and patient sex provided more appropriate indication for additional surgery with lymph node dissection after endoscopic treatment for T1 colorectal carcinomas.
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Miyachi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Shin-Ei
authors.initials: SE
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Katsuro
authors.initials: K
authors.lastname: Ichimasa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Hisayuki
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Oikawa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Matsudaira
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Kouyama
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Yui Jennifer
authors.initials: YJ
authors.lastname: Kimura
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Misawa
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ogata
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kudo
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Kodama
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Takemasa
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Wakamura
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Katagiri
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Baba
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Hidaka
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Ishida
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kohashi
authors.affiliation: Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.|Department of Pathology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Hamatani
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry / Q000556:secondary* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D003082:Colectomy / Q000379:methods*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery*; D003893:Desmin / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D015588:Observer Variation; D018579:Patient Selection; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D003893:Desmin
keywords: T1 colorectal cancer; lymph node metastasis; muscularis mucosae; risk factor