title: Apparent diffusion coefficient is a prognostic factor of head and neck squamous cell carcinoma treated with radiotherapy.
abstract: OBJECTIVE
  To evaluate the correlation between apparent diffusion coefficient (ADC) and prognosis in head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy.
  
  
  METHODS
  We retrospectively studied 41 patients (38 male and 3 female, ages 37-85 years) diagnosed with HNSCC (14 oropharynx, 22 hypopharynx, 4 larynx, 1 oral cavity) and treated with radiotherapy, with radiation dose to gross tumor volume over 60 Gy. The association between age, gender, performance status, tumor location, T stage, N stage, stage, dose, overall treatment time, treatment method, adjuvant therapy, or ADC and prognosis was analyzed using a Cox proportional hazard test.
  
  
  RESULTS
  ADC calculated with b-values of 300, 500, 750, and 1,000 s/mm(2) (ADC 300-1,000) alone showed a significant correlation with all of the analyses (p = 0.022 for local control, p = 0.0109 for regional control, p = 0.0041 for disease-free survival, and p = 0.0014 for overall survival). ADC calculated with b-values of 0, 100, and 200 s/mm(2) (ADC 0-200) showed a significant correlation with overall survival (p = 0.0012). N stage showed a significant correlation with regional control (p = 0.0241). Performance status showed significant association with local control (p = 0.0459), disease-free survival (p = 0.023), and overall survival (p = 0.0151), respectively.
  
  
  CONCLUSIONS
  ADC is an independent predictor of prognosis in HNSCC treated with radiotherapy.
authors.affiliation: Department of Diagnostic Radiology, School of Medicine, Sapporo Medical University, Minami 1, Nishi 17, Chuo-ku, Sapporo, 060-8556, Japan, mhatakenaka@sapmed.ac.jp.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hatakenaka
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hidetake
authors.initials: H
authors.lastname: Yabuuchi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Shioyama
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kamitani
authors.forename: Masato
authors.initials: M
authors.lastname: Yonezawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Torahiko
authors.initials: T
authors.lastname: Nakashima
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001834:Body Water / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000401:mortality* / Q000532:radiotherapy; D004058:Diffusion; D018572:Disease-Free Survival; D005260:Female; D006258:Head and Neck Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000532:radiotherapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D012189:Retrospective Studies