title: CT-based follow-up following radiotherapy or radiochemotherapy for locally advanced head and neck cancer; outcome and development of a prognostic model for regional control.
abstract: OBJECTIVE
  The purpose of this study was to make a prognostic model for regional relapse in head and neck cancer using clinical and CT parameters.
  
  
  METHODS
  183 patients with lymph node-positive head and neck cancer were treated between 2002 and 2012 with radiotherapy or concurrent chemoradiotherapy. CT studies pre- and post-treatment were reviewed for lymph node size and the presence of necrosis, extracapsular spread (ECS) and calcifications. For every patient, correlations with 3-year regional control (RC), metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS) were made.
  
  
  RESULTS
  3-year outcome rates were as follows: local control of 84%, RC of 80%, MFS of 74%, DFS of 61% and OS of 63%. Pre-treatment nodal size and the presence of necrosis were associated with a poorer outcome. This was also the case for post-treatment lymph node size, the presence of necrosis and ECS. We developed a CT-based prognostic model for RC with an area under the curve of 0.78 (95% confidence interval 0.63; 0.85).
  
  
  CONCLUSIONS
  We reached a good outcome in our patient cohort using a CT-based follow-up approach. A CT-based model was developed, which can aid in predicting RC. Advances in knowledge: A prognostic model is proposed, which can aid in predicting RC and the necessity for post-radiotherapy neck dissection using clinical parameters and parameters derived from the post-treatment CT study. This is the first article to propose a prognostic model for regional relapse in head and neck cancer based on these parameters.
authors.affiliation: 1 Department of Radiation Oncology, KU Leuven-University of Leuven, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Daan
authors.initials: D
authors.lastname: Nevens
authors.affiliation: 1 Department of Radiation Oncology, KU Leuven-University of Leuven, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Vantomme
authors.affiliation: 2 Leuven Biostatistics and Statistical Bioinformatics Centre, University of Leuven, Leuven, Belgium.
authors.forename: Annouschka
authors.initials: A
authors.lastname: Laenen
authors.affiliation: 3 Department of Radiology, KU Leuven-University of Leuven, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Robert
authors.initials: R
authors.lastname: Hermans
authors.affiliation: 1 Department of Radiation Oncology, KU Leuven-University of Leuven, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Sandra
authors.initials: S
authors.lastname: Nuyts
mesh_terms: D059248:Chemoradiotherapy; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D011379:Prognosis; D014057:Tomography, X-Ray Computed