title: Development, external validation and clinical usefulness of a practical prediction model for radiation-induced dysphagia in lung cancer patients.
abstract: BACKGROUND
  Acute dysphagia is a distressing dose-limiting toxicity occurring frequently during concurrent chemo-radiation or high-dose radiotherapy for lung cancer. It can lead to treatment interruptions and thus jeopardize survival. Although a number of predictive factors have been identified, it is still not clear how these could offer assistance for treatment decision making in daily clinical practice. Therefore, we have developed and validated a nomogram to predict this side-effect. In addition, clinical usefulness was assessed by comparing model predictions to physicians' predictions.
  
  
  METHODS
  Clinical data from 469 inoperable lung cancer patients, treated with curative intent, were collected prospectively. A prediction model for acute radiation-induced dysphagia was developed. Model performance was evaluated by the c-statistic and assessed using bootstrapping as well as two external datasets. In addition, a prospective study was conducted comparing model to physicians' predictions in 138 patients.
  
  
  RESULTS
  The final multivariate model consisted of age, gender, WHO performance status, mean esophageal dose (MED), maximum esophageal dose (MAXED) and overall treatment time (OTT). The c-statistic, assessed by bootstrapping, was 0.77. External validation yielded an AUC of 0.94 on the Ghent data and 0.77 on the Washington University St. Louis data for dysphagia ≥ grade 3. Comparing model predictions to the physicians' predictions resulted in an AUC of 0.75 versus 0.53, respectively.
  
  
  CONCLUSIONS
  The proposed model performed well was successfully validated and demonstrated the ability to predict acute severe dysphagia remarkably better than the physicians. Therefore, this model could be used in clinical practice to identify patients at high or low risk.
authors.affiliation: Department of Radiotherapy, Maastricht University Medical Center, University Maastricht, MAASTRO clinic, GROW, The Netherlands. cary.oberije@maastro.nl
authors.forename: Cary
authors.initials: C
authors.lastname: Dehing-Oberije
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ruysscher
authors.forename: Steven
authors.initials: S
authors.lastname: Petit
authors.forename: Jan
authors.initials: J
authors.lastname: Van Meerbeeck
authors.forename: Katrien
authors.initials: K
authors.lastname: Vandecasteele
authors.forename: Wilfried
authors.initials: W
authors.lastname: De Neve
authors.forename: Anne Marie C
authors.initials: AM
authors.lastname: Dingemans
authors.forename: Issam
authors.initials: I
authors.lastname: El Naqa
authors.forename: Joseph
authors.initials: J
authors.lastname: Deasy
authors.forename: Jeff
authors.initials: J
authors.lastname: Bradley
authors.forename: Ellen
authors.initials: E
authors.lastname: Huang
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
mesh_terms: D000208:Acute Disease; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D003680:Deglutition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D008297:Male; D015233:Models, Statistical; D049451:Nomograms; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D055752:Small Cell Lung Carcinoma / Q000532:radiotherapy*
chemical_list: D000970:Antineoplastic Agents