title: Clinical impact of a strategy involving endoscopic submucosal dissection for early gastric cancer: determining the optimal pathway.
abstract: BACKGROUND
  Endoscopic submucosal dissection (ESD) is a technique developed to enable the endoscopic resection (ER) of large and ulcerative neoplastic lesions that were previously unresectable using conventional endoscopic mucosal resection (EMR). We investigated the clinical outcomes of ER of early gastric cancer (EGC) before and after the introduction of ESD, with particular attention to surgery and its potential consequences.
  
  
  METHODS
  We reviewed 2,785 consecutive surgical patients with EGC and 2,469 consecutive lesions treated by ER with curative intent between 1990 and 2005. The study was divided into an EMR period (1990-1999) and an ESD period (2000-2005). We analyzed the clinical outcomes of endoscopic and surgical resections and defined 'potentially avoidable surgery' as cases of surgery performed for lesions curable by ER.
  
  
  RESULTS
  The rate of potentially avoidable surgery was 3.8% (52/1,369) in the EMR period and 0.2% (3/1,416) in the ESD period (P < 0.001). For ER patients, the rate of overall non-curative ER was 36.9% (154/417) in the EMR group and 17.0% (348/2,052) in the ESD group (P < 0.001). The rate of non-curative ER for lesions defined as having 'positive or difficult to estimate horizontal margins only' decreased significantly, from 26.1% (109/417) in the EMR group to 1.4% (29/2,052) in the ESD group (P < 0.001). Conversely, the rate of non-curative ER for lesions defined as having 'possible lymph node metastasis' significantly increased in the ESD group (15.5%; 319/2,052) compared to that in the EMR group (10.8%; 45/417) (P < 0.01).
  
  
  CONCLUSIONS
  The application of a pathway involving ESD resulted in a significant decrease in the rate of potentially avoidable surgery, highlighting the advantages associated with performing ESD.
authors.affiliation: Endoscopy Division, National Cancer Center Hospital, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Nonaka
authors.forename: Ichiro
authors.initials: I
authors.lastname: Oda
authors.forename: Teruo
authors.initials: T
authors.lastname: Nakaya
authors.forename: Chika
authors.initials: C
authors.lastname: Kusano
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Suzuki
authors.forename: Shigetaka
authors.initials: S
authors.lastname: Yoshinaga
authors.forename: Takeo
authors.initials: T
authors.lastname: Fukagawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Katai
authors.forename: Takuji
authors.initials: T
authors.lastname: Gotoda
mesh_terms: D004210:Dissection / Q000379:methods; D055088:Early Detection of Cancer; D016099:Endoscopy, Gastrointestinal / Q000379:methods* / Q000706:statistics & numerical data; D005753:Gastric Mucosa / Q000601:surgery; D006801:Humans; D008207:Lymphatic Metastasis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000601:surgery*; D016896:Treatment Outcome; D019564:Unnecessary Procedures / Q000706:statistics & numerical data