title: External validation of nomogram for the prediction of recurrence after curative resection in early gastric cancer.
abstract: BACKGROUND
  Nomograms are statistics-based tools that provide the overall probability of a specific outcome. In our previous study, we developed a nomogram that predicts recurrence of early gastric cancer (EGC) after curative resection. We carried out this study to externally validate our EGC nomogram.
  
  
  METHODS
  The EGC nomogram was established from a retrospective EGC database that included 2923 consecutive patients. This nomogram was independently externally validated for a cohort of 1058 consecutive patients. For the EGC nomogram validation, we assessed both discrimination and calibration.
  
  
  RESULTS
  Within the follow-up period (median 37 months), a total of 11 patients (1.1%) experienced recurrence. The concordance index (c-index) was 0.7 (P = 0.02) and the result of the overall C index was 0.82 [P = 0.006, 95% confidence interval (CI) 0.59-1.00]. The goodness of fit test showed that the EGC nomogram had significantly good fit for 1- and 2-year survival intervals (P = 0.998 and 0.879, respectively). The actual and predicted survival outcomes showed good agreement, suggesting that the survival predictions from the nomogram are well calibrated externally.
  
  
  CONCLUSIONS
  A preexisting nomogram for predicting disease-free survival (DFS) of EGC after surgery was externally validated. The nomogram is useful for accurate and individual prediction of DFS, patient prognostication, counseling, and follow-up planning.
authors.affiliation: Yonsei Cancer Center, Yonsei Cancer Research Institute, Seoul, Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: H S
authors.initials: HS
authors.lastname: Kim
authors.forename: W Y
authors.initials: WY
authors.lastname: Seo
authors.forename: C M
authors.initials: CM
authors.lastname: Nam
authors.forename: K Y
authors.initials: KY
authors.lastname: Kim
authors.forename: H C
authors.initials: HC
authors.lastname: Jeung
authors.forename: J F
authors.initials: JF
authors.lastname: Lai
authors.forename: H C
authors.initials: HC
authors.lastname: Chung
authors.forename: S H
authors.initials: SH
authors.lastname: Noh
authors.forename: S Y
authors.initials: SY
authors.lastname: Rha
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D049451:Nomograms; D011379:Prognosis; D013274:Stomach Neoplasms / Q000473:pathology / Q000601:surgery*