title: Mandibular osteoradionecrosis in squamous cell carcinoma of the oral cavity and oropharynx: incidence and risk factors.
abstract: OBJECTIVE
  Mandibular osteoradionecrosis (ORN) is a serious complication of radiotherapy (RT) in head and neck cancer patients. The aim of this study was to analyze the incidence of and risk factors for mandibular ORN in squamous cell carcinoma (SCC) of the oral cavity and oropharynx.
  
  
  METHODS
  Case series with chart review.
  
  
  METHODS
  University tertiary care center for head and neck oncology.
  
  
  METHODS
  Seventy-three patients treated for stage I to IV SCC of the oral cavity and oropharynx between 2000 and 2007, with a minimum follow-up of 2 years, were included in the study. Treatment modalities included both RT with curative intent and adjuvant RT following tumor surgery. The log-rank test and Cox model were used for univariate and multivariate analyses.
  
  
  RESULTS
  The incidence of mandibular ORN was 40% at 5 years. Using univariate analysis, the following risk factors were identified: oral cavity tumors (P < .01), bone invasion (P < .02), any surgery prior to RT (P < .04), and bone surgery (P < .0001). By multivariate analysis, mandibular surgery proved to be the most important risk factor and the only one reaching statistical significance (P < .0002).
  
  
  CONCLUSIONS
  Mandibular ORN is a frequent long-term complication of RT for oral cavity and oropharynx cancers. Mandibular surgery before irradiation is the only independent risk factor. These aspects must be considered when planning treatment for these tumors.
authors.affiliation: Otolaryngology, Head and Neck Surgery Department, Lausanne University Hospital (CHUV), Lausanne, Switzerland.
authors.forename: Yan
authors.initials: Y
authors.lastname: Monnier
authors.forename: Martin
authors.initials: M
authors.lastname: Broome
authors.forename: Michael
authors.initials: M
authors.lastname: Betz
authors.forename: Kahina
authors.initials: K
authors.lastname: Bouferrache
authors.forename: Mahmut
authors.initials: M
authors.lastname: Ozsahin
authors.forename: Bertrand
authors.initials: B
authors.lastname: Jaques
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008336:Mandibular Diseases / Q000453:epidemiology* / Q000209:etiology*; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000532:radiotherapy*; D009959:Oropharyngeal Neoplasms / Q000532:radiotherapy*; D010025:Osteoradionecrosis / Q000453:epidemiology* / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors