title: Using the TNM system to predict survival in squamous cell carcinoma of the head and neck.
abstract: OBJECTIVE
  To create a classification system for prognosis based on the TNM system for patients with squamous cell carcinoma of the Head and Neck such that patient groupings are homogeneous within and heterogenous between.
  
  
  METHODS
  655 consecutive patients with invasive squamous cell carcinoma of the Head and Neck followed prospectively are split into a training set and a test set. Using the training set, the Cox Proportional Hazards Model and the outcome of dead with disease, we create homogenous prognostic levels based on relative risk. Using the test set, we compare our model to others in the literature.
  
  
  RESULTS
  Using the training set we identify 5 prognostic levels and using the test set we demonstrate that our model is superior to others for both within group homogeneity and between group heterogeneity.
  
  
  CONCLUSIONS
  A simple classification system can be used to group patients for survival and is valid for future study in prognostication.
authors.affiliation: Department of Otolaryngology, Queen's University, Kingston, Ont., Canada.
authors.forename: S F
authors.initials: SF
authors.lastname: Hall
authors.forename: P A
authors.initials: PA
authors.lastname: Groome
authors.forename: D
authors.initials: D
authors.lastname: Rothwell
authors.forename: P F
authors.initials: PF
authors.lastname: Dixon
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000145:classification / Q000401:mortality* / Q000473:pathology*; D005260:Female; D006258:Head and Neck Neoplasms / Q000145:classification / Q000401:mortality* / Q000473:pathology*; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models