title: A clinical staging system and treatment guidelines for maxillary osteoradionecrosis in irradiated nasopharyngeal carcinoma patients.
abstract: OBJECTIVE
  To develop a clinical staging system for maxillary osteoradionecrosis (ORN) in irradiated nasopharyngeal carcinoma (NPC) patients.
  
  
  METHODS
  The data of maxillary ORN cases among 1,758 irradiated NPC patients were analyzed. A staging system based on the degrees of bone exposure (E), infection (I), and bleeding (B) was developed. Correlations between various clinical parameters and stages of maxillary ORN and relationships between treatment modalities and outcomes at each stage were evaluated. Cumulative success of treatment and risk factors that affect treatment outcomes were analyzed.
  
  
  RESULTS
  The incidence of maxillary ORN was 2.7% (48/1,758). TNM stage of NPC (p < 0.001), radiation dose (p = 0.029), and tooth extraction (p < 0.001) appeared to have significant influences on disease severity. Success rates between conservative therapy and surgical treatment were not significantly different for Stage I ORN but differed significantly for Stage II (p = 0.013) and Stage III (p = 0.008) lesions. Grade 3 infection and bleeding significantly jeopardized treatment success (p = 0.043 and 0.015, respectively). The risk ratios of treatment failure for Grade 3 infection and bleeding were 2.523 (p = 0.034) and 3.141 (p = 0.027), respectively.
  
  
  CONCLUSIONS
  More serious maxillary ORN tended to occur in cases with more advanced NPC, higher radiation dose, and history of tooth extraction. Surgical treatment was usually required in Stage II and III ORN. The grades of infection and bleeding are important factors in guidance of treatment and prediction of outcomes.
authors.affiliation: Division of Oral and Maxillofacial Surgery, Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Shih-Jung
authors.initials: SJ
authors.lastname: Cheng
authors.forename: Jang-Jaer
authors.initials: JJ
authors.lastname: Lee
authors.forename: Lai-Lei
authors.initials: LL
authors.lastname: Ting
authors.forename: I-Yun
authors.initials: IY
authors.lastname: Tseng
authors.forename: Hao-Hueng
authors.initials: HH
authors.lastname: Chang
authors.forename: Hsin-Ming
authors.initials: HM
authors.lastname: Chen
authors.forename: Ying-Shiung
authors.initials: YS
authors.lastname: Kuo
authors.forename: Liang-Jiunn
authors.initials: LJ
authors.lastname: Hahn
authors.forename: Sang-Heng
authors.initials: SH
authors.lastname: Kok
mesh_terms: D005260:Female; D017408:Guidelines as Topic; D006801:Humans; D008297:Male; D008439:Maxillary Diseases / Q000473:pathology / Q000628:therapy*; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D010025:Osteoradionecrosis / Q000473:pathology / Q000628:therapy*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013223:Statistics as Topic