title: Apparent diffusion coefficient modifications in assessing gastro-oesophageal cancer response to neoadjuvant treatment: comparison with tumour regression grade at histology.
abstract: OBJECTIVE
  To assess changes in apparent diffusion coefficient (ΔADC) and volume (ΔV) after neoadjuvant treatment (NT), and tumour regression grade (TRG) in gastro-oesophageal cancers (GEC), and to discriminate responders from non-responders.
  
  
  METHODS
  Thirty-two patients with biopsy-proven locally-advanced GEC underwent diffusion weighted magnetic resonance imaging (DWI) pre- and post-NT. Lesion ADC, volume, ΔADC and ΔV were calculated. TRG 1-2-3 patients were classified as R; TRG 4-5 as non-responders. ΔADC-TRG and ΔV-TRG correlations, pre-NT and post-NT ADC, ΔADC and ΔV cut-off values for responders and non-responders were calculated. Two readers measured mean tumour ADCs and interobserver variability was calculated. (Spearman's and intraclass correlation coefficient [ICC]).
  
  
  RESULTS
  The interobserver reproducibility was very good both for pre-NT (Spearman's rho = 0.8160; ICC = 0.8993) and post-NT (Spearman's rho = 0.8357; ICC = 0.8663). Responders showed lower pre-NT ADC (1.32 versus 1.63 × 10(-3) mm(2)/s; P = 0.002) and higher post-NT ADC (2.22 versus 1.51 × 10(-3) mm(2)/s; P = 0.001) than non-responders and ADC increased in responders (ΔADC, 85.45 versus -8.21 %; P = 0.00005). ΔADC inversely correlated with TRG (r = -0.71, P = 0.000004); no difference in ΔV between responders and non-responders (-50.92 % versus -14.12 %; P = 0.068) and no correlation ΔV-TRG (r = 0.02 P = 0.883) were observed.
  
  
  CONCLUSIONS
  The ADC can be used to assess gastro-oesophageal tumour response to neoadjuvant treatment as a reliable expression of tumour regression.
  
  
  CONCLUSIONS
  • DWI is now being used to assess many cancers. • Change in ADC measurements offer new information about oesophageal tumours. • ADC changes are more reliable than dimensional criteria in assessing neoadjuvant treatment. • Such ADC assessment could optimise management of locally advanced gastro-oesophageal cancers.
authors.affiliation: Department of Radiology and Center for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy. decobelli.francesco@hsr.it
authors.forename: Francesco
authors.initials: F
authors.lastname: De Cobelli
authors.forename: Francesco
authors.initials: F
authors.lastname: Giganti
authors.forename: Elena
authors.initials: E
authors.lastname: Orsenigo
authors.forename: Michaela
authors.initials: M
authors.lastname: Cellina
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.forename: Giulia
authors.initials: G
authors.lastname: Agostini
authors.forename: Luca
authors.initials: L
authors.lastname: Albarello
authors.forename: Elena
authors.initials: E
authors.lastname: Mazza
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ambrosi
authors.forename: Carlo
authors.initials: C
authors.lastname: Socci
authors.forename: Carlo
authors.initials: C
authors.lastname: Staudacher
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging; D004938:Esophageal Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy / Q000379:methods*; D060787:Neoplasm Grading; D015588:Observer Variation; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D016896:Treatment Outcome