title: Use of machine learning methods for prediction of acute toxicity in organs at risk following prostate radiotherapy.
abstract: OBJECTIVE
  The goal of this study is to investigate the advantages of large scale optimization methods vs conventional classification techniques in predicting acute toxicity for urinary bladder and rectum due to prostate irradiation.
  
  
  METHODS
  Clinical and dosimetric data of 321 patients undergoing prostate conformal radiotherapy were recorded. Gastro-intestinal and genito-urinary acute toxicities were scored according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) scale. Patients were classified in two categories to separate mild (Grade < 2) from severe toxicity levels (Grade > 2). Machine learning methods at different complexity were implemented to predict toxicity as a function of multiple variables. The first approach consisted of a large scale optimization method, based on genetic algorithms (GAs) and artificial neural networks (ANN). The second approach was a binary classifier based on support vector machines (SVM).
  
  
  RESULTS
  The ANN and SVM-based solutions showed comparable prediction accuracy, exhibiting an area under the receiver operating characteristic (ROC) curve of 0.7. Different sensitivity and specificity features were measured for the two approaches. The ANN algorithm showed enhanced sensitivity if combined with appropriate classification criteria.
  
  
  CONCLUSIONS
  The results demonstrate that high sensitivity in toxicity prediction can be achieved with optimized ANNs, that are put forward to represent a valuable support in medical decisions. Future studies will be focused on enlarging the available patient database to increase the reliability of toxicity prediction algorithms and to define optimal classification criteria.
authors.affiliation: TBMLab, Department of Bioengineering, Politecnico di Milano University, 20133 Milano, Italy. andrea.pella@polimi.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Pella
authors.forename: Raffaella
authors.initials: R
authors.lastname: Cambria
authors.forename: Marco
authors.initials: M
authors.lastname: Riboldi
authors.forename: Barbara Alicja
authors.initials: BA
authors.lastname: Jereczek-Fossa
authors.forename: Cristiana
authors.initials: C
authors.lastname: Fodor
authors.forename: Dario
authors.initials: D
authors.lastname: Zerini
authors.forename: Ahmad Esmaili
authors.initials: AE
authors.lastname: Torshabi
authors.forename: Federica
authors.initials: F
authors.lastname: Cattani
authors.forename: Cristina
authors.initials: C
authors.lastname: Garibaldi
authors.forename: Guido
authors.initials: G
authors.lastname: Pedroli
authors.forename: Guido
authors.initials: G
authors.lastname: Baroni
authors.forename: Roberto
authors.initials: R
authors.lastname: Orecchia
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001185:Artificial Intelligence; D006801:Humans; D008297:Male; D008875:Middle Aged; D016571:Neural Networks, Computer; D058958:Organs at Risk / Q000528:radiation effects*; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011786:Quality Control; D011832:Radiation Injuries; D011880:Radiotherapy Planning, Computer-Assisted