title: The accuracy of three predictive models in the evaluation of recurrence rates for gastrointestinal stromal tumors.
abstract: BACKGROUND
  Treatment decisions for gastrointestinal stromal tumors (GIST) are frequently guided by tumor characteristics. An accurate prediction of recurrence is important to determine the benefit from targeted therapy. Our goal was to compare the concordance of three validated risk stratification schemes with observed outcomes in patients undergoing resection for GISTs.
  
  
  METHODS
  Patients who underwent surgery for GISTs from 2001 to 2011 at a tertiary centre were identified. Survival was evaluated using the Kaplan-Meier product-limit method. Cox proportional hazard models were used to obtain predicted recurrence for each system and concordance indices were calculated.
  
  
  RESULTS
  Of 110 patients identified, 77 (70.0%) had surgery and 29 (26.4%) also received adjuvant therapy. The majority of patients had tumors that were very low (4.5%), low (32.7%), or intermediate (22.7%) in terms of malignant potential. R0 resection was achieved in 89.1% of cases. Observed 2-year and 5-year recurrence rates were significantly lower than those predicted by the Memorial Sloan Kettering Cancer Center nomogram (7.6% vs. 19.3% and 18.4% vs. 27.0%); however, it was the most favorable tool compared to the US National Institutes of Health (NIH)-consensus (P = 0.0017) and modified NIH-consensus (P < 0.001), with a concordance index of 0.811.
  
  
  CONCLUSIONS
  Development of a novel predictive tool that includes additional prognostic factors may better stratify recurrence following resection for GIST.
authors.affiliation: Department of Surgical Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Racz
authors.forename: Savtaj S
authors.initials: SS
authors.lastname: Brar
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Cleghorn
authors.forename: M Carolina
authors.initials: MC
authors.lastname: Jimenez
authors.forename: Arash
authors.initials: A
authors.lastname: Azin
authors.forename: Eshetu G
authors.initials: EG
authors.lastname: Atenafu
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Jackson
authors.forename: Allan
authors.initials: A
authors.lastname: Okrainec
authors.forename: Fayez A
authors.initials: FA
authors.lastname: Quereshy
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000473:pathology* / Q000628:therapy; D046152:Gastrointestinal Stromal Tumors / Q000473:pathology* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*
keywords: gastrointestinal stromal tumor; nomograms; recurrence risk; risk stratification schemes