title: Radiation-induced trismus in the ARTSCAN head and neck trial.
abstract: Trismus, a well-known sequelae after treatment of head and neck cancer, decreases a patient's oral function and quality of life. The main objectives of this study were to: 1) investigate the long-term prevalence of radiation-induced trismus in patients treated for head and neck cancer according to two different fractionation schedules; and 2) model a dose-response relationship for trismus.
  
  
  METHODS
  Patients were recruited from the Swedish ARTSCAN trial, a prospective randomised multicentre study comparing conventional and accelerated fractionation. A total of 124 patients agreed to a clinical ENT examination 21-127 months (median 66 months) after beginning radiation therapy. Trismus-related scores were assessed using the EORTC H&N35 Quality of Life questionnaire. The TheraBite(®) range of motion scale was used to measure maximal interincisal distance. The dose-response relationship for structures important for mastication and the temporomandibular joints was investigated by normal tissue complication probability modelling.
  
  
  RESULTS
  No significant differences in patient-reported trismus or maximal interincisal distance were found between the two trial arms. Patient-reported moderate to high scores regarding trismus increased from 3% at the start of radiation therapy to 25% at the long-term follow-up. Maximal interincisal distance correlated significantly with patient-reported scores of trismus. The best dose-response fit to the endpoint data was found for the dose to the ipsilateral masseter.
  
  
  CONCLUSIONS
  Trismus is a persistent complication after radiotherapy with 3D-conformal radiation therapy. We found no difference between the severity and prevalence of trismus between conventional and accelerated fractionation, but a significant correlation between the absorbed dose to the mastication structures and opening of the mouth. Further prospective studies may determine whether a reduced dose to structures important for mastication using intensity-modulated radiation therapy will reduce problems with trismus.
authors.affiliation: Department of Clinical Sciences, Otorhinolaryngology, Lund University , Lund , Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Lindblom
authors.forename: Ola
authors.initials: O
authors.lastname: Gärskog
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kjellén
authors.forename: Göran
authors.initials: G
authors.lastname: Laurell
authors.forename: Eva
authors.initials: E
authors.lastname: Levring Jäghagen
authors.forename: Peter
authors.initials: P
authors.lastname: Wahlberg
authors.forename: Björn
authors.initials: B
authors.lastname: Zackrisson
authors.forename: Per
authors.initials: P
authors.lastname: Nilsson
mesh_terms: D000328:Adult; D000368:Aged; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011788:Quality of Life; D011878:Radiotherapy / Q000009:adverse effects*; D014313:Trismus / Q000453:epidemiology* / Q000209:etiology*