title: Trismus in patients with oropharyngeal cancer: relationship with dose in structures of mastication apparatus.
abstract: BACKGROUND
  Our aim was to assess the correlation between the radiation therapy (RT) dose to the mastication apparatus and trismus of oropharyngeal cancer patients.
  
  
  METHODS
  Eighty-one patients treated with RT were analyzed. The masseter, pterygoid, and temporalis muscles and the coronoid and condyl were delineated on axial CT slices. The mean dose in these structures was correlated with outcome of quality of life questionnaires.
  
  
  RESULTS
  Fifty-six (88%) patients responded; 16% of the patients scored grade 3/4 on the Head & Neck 35 "opening mouth" question. A significant correlation was observed between dose in masseter and pterygoid muscles and trismus (p= .02).
  
  
  CONCLUSIONS
  Patients treated with brachytherapy received a lower dose in masticatory muscles. A steep dose-effect relationship between mean dose in masseter muscle and pterygoid muscles and the probability of having trismus complaints was observed; with every additional 10 Gy to the pterygoid muscle, an increase of the probability of trismus of 24% was observed.
authors.affiliation: Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
authors.forename: David N
authors.initials: DN
authors.lastname: Teguh
authors.forename: Peter C
authors.initials: PC
authors.lastname: Levendag
authors.forename: Peter
authors.initials: P
authors.lastname: Voet
authors.forename: Henri
authors.initials: H
authors.lastname: van der Est
authors.forename: Inge
authors.initials: I
authors.lastname: Noever
authors.forename: Willy
authors.initials: W
authors.lastname: de Kruijf
authors.forename: Peter
authors.initials: P
authors.lastname: van Rooij
authors.forename: Paul I M
authors.initials: PI
authors.lastname: Schmitz
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Heijmen
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000528:radiation effects*; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D011626:Pterygoid Muscles / Q000528:radiation effects*; D011788:Quality of Life; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods; D011879:Radiotherapy Dosage; D011795:Surveys and Questionnaires; D014313:Trismus / Q000145:classification / Q000209:etiology*