title: Fractional change in apparent diffusion coefficient as an imaging biomarker for predicting treatment response in head and neck cancer treated with chemoradiotherapy.
abstract: OBJECTIVE
  ADC provides a measure of water molecule diffusion in tissue. The aim of this study was to evaluate whether the fractional change in ADC during therapy can be used as a valid predictive indicator of treatment response in head and neck squamous cell carcinoma treated with chemoradiotherapy.
  
  
  METHODS
  Forty patients underwent DWI at pretreatment and 3 weeks after the start of treatment. The pretreatment ADC, fractional change in ADC, tumor regression rate, and other clinical variables were compared with locoregional control and locoregional failure and were analyzed by using logistic regression analysis and receiver operating characteristic analysis. Furthermore, progression-free survival curves divided by the corresponding threshold value were compared by means of the log-rank test.
  
  
  RESULTS
  The fractional change in ADCprimary, the fractional change in ADCnode, primary tumor volume, nodal volume, tumor regression ratenode, N stage, and tumor location revealed significant differences between locoregional failure and locoregional control (P < .05). In univariate analysis, the fractional change in ADCprimary, fractional change in ADCnode, tumor regression ratenode, N stage, and tumor location showed significant association with locoregional control (P < .05). In multivariate analysis, however, only the fractional change in ADCprimary was identified as a significant and independent predictor of locoregional control (P = .04). A threshold fractional change in ADCprimary of 0.24 revealed a sensitivity of 100%, specificity of 78.7%, and overall accuracy of 84.8% for the prediction of locoregional control. Progression-free survival of the 2 groups divided by the fractional change in ADCprimary at 0.24 showed a significant difference (P < .05).
  
  
  CONCLUSIONS
  The results suggest that the fractional change in ADCprimary is a valid imaging biomarker for predicting treatment response in head and neck squamous cell carcinoma treated with chemoradiotherapy.
authors.affiliation: From the Departments of Radiology (M.M., I.T., Y.K., H. Tonami).
authors.forename: M
authors.initials: M
authors.lastname: Matoba
authors.forename: H
authors.initials: H
authors.lastname: Tuji
authors.forename: Y
authors.initials: Y
authors.lastname: Shimode
authors.forename: I
authors.initials: I
authors.lastname: Toyoda
authors.forename: Y
authors.initials: Y
authors.lastname: Kuginuki
authors.forename: K
authors.initials: K
authors.lastname: Miwa
authors.forename: H
authors.initials: H
authors.lastname: Tonami
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000628:therapy*; D059248:Chemoradiotherapy / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000077195:Squamous Cell Carcinoma of Head and Neck; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers
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