title: Incidence of lymph node metastasis and the feasibility of endoscopic resection for undifferentiated-type early gastric cancer.
abstract: BACKGROUND
  Endoscopic resection (ER) has been accepted as minimally invasive treatment in patients with early gastric cancer (EGC) who have a negligible risk of lymph node metastasis. It has already been determined which lesions in differentiated-type EGC present a negligible risk of lymph node metastasis, and ER is being performed for these lesions. In contrast, no consensus has been reached on which lesions in undifferentiated-type (UD-type) EGC present a negligible risk for lymph node metastasis, nor have indications for ER for UD-type EGC been established.
  
  
  METHODS
  We investigated 3843 patients who had undergone gastrectomy with lymph node dissection for solitary UD-type EGC at the Cancer Institute Hospital, Tokyo, and the National Cancer Center Hospital, Tokyo. Seven clinicopathological factors were assessed for their possible association with lymph node metastasis.
  
  
  RESULTS
  Of the 3843 patients, 2163 (56.3%) had intramucosal cancers and 1680 (43.7%) had submucosal invasive cancers. Only 105 (4.9%) intramucosal cancers compared with 399 (23.8%) submucosal invasive cancers were associated with lymph node metastases. By multivariate analysis, tumor size 21 mm or more, lymphatic-vascular capillary involvement, and submucosal penetration were independent risk factors for lymph node metastasis (P < 0.001, respectively). None of the 310 intramucosal cancers 20 mm or less in size without lymphatic- vascular capillary involvement and ulcerative findings was associated with lymph node metastases (95% confidence interval, 0-0.96%).
  
  
  CONCLUSIONS
  UD-type intramucosal EGC 20 mm or less in size without lymphatic-vascular capillary involvement and ulcerative findings presents a negligible risk of lymph node metastasis. We propose that in this circumstance ER could be considered.
authors.affiliation: Department of Gastroenterology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-10-6 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Hirasawa
authors.forename: Takuji
authors.initials: T
authors.lastname: Gotoda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Miyata
authors.forename: You
authors.initials: Y
authors.lastname: Kato
authors.forename: Tadakazu
authors.initials: T
authors.lastname: Shimoda
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Junko
authors.initials: J
authors.lastname: Fujisaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sano
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology / Q000601:surgery*; D005773:Gastroscopy / Q000379:methods*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D011446:Prospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*