title: Defining a Subgroup Treatable for Laparoscopic and Endoscopic Cooperative Surgery in Undifferentiated Early Gastric Cancer: the Role of Lymph Node Metastasis.
abstract: BACKGROUND
  Recently, the use of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) and the development of laparoscopic and endoscopic cooperative surgery (LECS) have enabled either the preservation of the stomach or the minimization of the extent of partial resection. ESD has recently been practiced on a differentiated type of EGC. However, there is no clear evidence for endoscopic treatments of undifferentiated EGC. The purposes of this study are to investigate predictive factors of lymph node metastasis (LNM) in undifferentiated EGC and expand the possibility of using LECS for the treatment of undifferentiated EGC.
  
  
  METHODS
  Data from 116 patients with undifferentiated EGC and surgically treated were collected, and the association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. Odds ratios (OR) with 95 % confidence interval (95 % CI) were calculated.
  
  
  RESULTS
  The tumor size (OR = 11.748, 95 % CI 2.034-62.213, P = 0.008), depth of invasion (OR = 13.928, 95 % CI 1.971-92.434, P = 0.016), and lymphatic vessel involvement (OR = 11.522, 95 % CI 2.645-59.172, P = 0.021) that were significantly associated with LNM by univariate analysis were found to be significant and independent risk factors for LNM by multivariate analysis. The LNM rate was 5.9 % (4/68) and 29.2 % (14/48) with intramucosal and submucosal undifferentiated EGC, respectively. LNM was observed in 66.7 % (2/3) of patients with both risk factors (tumor larger than or equal to 2.0 cm and the presence of lymphatic vessel involvement (LVI)), but in none of 36 patients without the two risk factors in intramucosal undifferentiated EGC. The 5-year survival rates were 88.9, 72.4, and 33.3 %, respectively, in cases with none, one, and two of the risk factors, respectively, in intramucosal undifferentiated EGC (P < 0.05).
  
  
  CONCLUSIONS
  ESD alone may be a sufficient treatment for intramucosal undifferentiated EGC if the tumor is less than 2.0 cm in size and when LVI is absent upon postoperative histological examination. LECS is feasible and safe for patients with undifferentiated EGC.
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.|Department of Surgical Oncology, Affiliated Xing Tai People Hospital of Hebei Medial University, Xingtai, 054001, Hebei Province, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China. chenlinbj301@126.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Surgical Oncology, Affiliated Xing Tai People Hospital of Hebei Medial University, Xingtai, 054001, Hebei Province, China.
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Huo
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Xi
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Cui
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhao
mesh_terms: D055088:Early Detection of Cancer; D005260:Female; D005743:Gastrectomy / Q000379:methods*; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000601:surgery*
keywords: Clinicopathological characteristics; Early gastric cancer; Laparoscopic and endoscopic cooperative surgery; Lymph node metastasis; Undifferentiated early gastric cancer