title: Random forests to predict rectal toxicity following prostate cancer radiation therapy.
abstract: OBJECTIVE
  To propose a random forest normal tissue complication probability (RF-NTCP) model to predict late rectal toxicity following prostate cancer radiation therapy, and to compare its performance to that of classic NTCP models.
  
  
  METHODS
  Clinical data and dose-volume histograms (DVH) were collected from 261 patients who received 3-dimensional conformal radiation therapy for prostate cancer with at least 5 years of follow-up. The series was split 1000 times into training and validation cohorts. A RF was trained to predict the risk of 5-year overall rectal toxicity and bleeding. Parameters of the Lyman-Kutcher-Burman (LKB) model were identified and a logistic regression model was fit. The performance of all the models was assessed by computing the area under the receiving operating characteristic curve (AUC).
  
  
  RESULTS
  The 5-year grade ≥2 overall rectal toxicity and grade ≥1 and grade ≥2 rectal bleeding rates were 16%, 25%, and 10%, respectively. Predictive capabilities were obtained using the RF-NTCP model for all 3 toxicity endpoints, including both the training and validation cohorts. The age and use of anticoagulants were found to be predictors of rectal bleeding. The AUC for RF-NTCP ranged from 0.66 to 0.76, depending on the toxicity endpoint. The AUC values for the LKB-NTCP were statistically significantly inferior, ranging from 0.62 to 0.69.
  
  
  CONCLUSIONS
  The RF-NTCP model may be a useful new tool in predicting late rectal toxicity, including variables other than DVH, and thus appears as a strong competitor to classic NTCP models.
authors.affiliation: LTSI, Université de Rennes 1, Rennes, France; INSERM, U1099, Rennes, France; Escuela de Estadística, Universidad Nacional de Colombia Sede Medellín, Medellín, Colombia.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Ospina
authors.affiliation: LTSI, Université de Rennes 1, Rennes, France; Laboratory of Image Science and Technology, Southeast University, Nanjing, PR China; Department of Radiation Physics, Shandong Cancer Hospital and Institute, Jinan, PR China; Centre de Recherche en Information Biomédical Sino-Français, Rennes, France.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Département de Radiothérapie, Centre Eugène Marquis, Rennes, France.
authors.forename: Ciprian
authors.initials: C
authors.lastname: Chira
authors.affiliation: Département de Radiothérapie, Institut Gustave-Roussy, Villejuif, France.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bossi
authors.affiliation: Département de Radiothérapie, Centre Eugène Marquis, Rennes, France.
authors.forename: Jean B
authors.initials: JB
authors.lastname: Delobel
authors.affiliation: Département de Radiothérapie, Centre Alexis Vautrin, Nancy, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Beckendorf
authors.affiliation: Département de Radiothérapie, CRLCC Henri Becquerel, Rouen, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Dubray
authors.affiliation: Département de Radiothérapie, Hôpital Henri Mondor, Créteil, France.
authors.forename: Jean-Léon
authors.initials: JL
authors.lastname: Lagrange
authors.affiliation: Escuela de Estadística, Universidad Nacional de Colombia Sede Medellín, Medellín, Colombia.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Correa
authors.affiliation: LTSI, Université de Rennes 1, Rennes, France; INSERM, U1099, Rennes, France; Centre de Recherche en Information Biomédical Sino-Français, Rennes, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Simon
authors.affiliation: LTSI, Université de Rennes 1, Rennes, France; INSERM, U1099, Rennes, France.
authors.forename: Oscar
authors.initials: O
authors.lastname: Acosta
authors.affiliation: LTSI, Université de Rennes 1, Rennes, France; INSERM, U1099, Rennes, France; Département de Radiothérapie, Centre Eugène Marquis, Rennes, France; Centre de Recherche en Information Biomédical Sino-Français, Rennes, France. Electronic address: r.de-crevoisier@rennes.unicancer.fr.
authors.forename: Renaud
authors.initials: R
authors.lastname: de Crevoisier
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D019540:Area Under Curve; D006471:Gastrointestinal Hemorrhage / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011336:Probability; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D012372:ROC Curve; D011832:Radiation Injuries / Q000150:complications / Q000453:epidemiology*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D012007:Rectum / Q000528:radiation effects*; D012189:Retrospective Studies
chemical_list: D000925:Anticoagulants