title: Prognostic utility of diffusion-weighted MRI in oesophageal cancer: is apparent diffusion coefficient a potential marker of tumour aggressiveness?
abstract: OBJECTIVE
  To investigate the role of the apparent diffusion coefficient (ADC) as a potential prognostic biomarker in the evaluation of the aggressiveness of oesophageal cancer.
  
  
  METHODS
  Between November 2009 and December 2013, 43 patients with evidence of oesophageal or oesophago-gastric junction cancer were referred to our institution and prospectively entered in our database. The final study population consisted of 23 patients (18 men; 5 women; mean age, 64.62 ± 10.91 years) who underwent diffusion-weighted Magnetic Resonance before surgical intervention. Specifically, 14 were directly treated with surgery and 9 were addressed to chemo/radiotherapy beforehand. Two radiologists independently measured mean tumour ADC and inter-observer agreement (Spearman's and intraclass correlation coefficient [ICC]) was assessed. In the univariate analysis, overall survival curves related to pathological ADC, pT, pN, tumour location and histotype were fitted using the Kaplan-Meier method. Survival curves were then compared using the log-rank test.
  
  
  RESULTS
  Inter-observer reproducibility was very good (Spearman's rho = 0.95; ICC = 0.94). At a total median follow-up of 19 months (2-49 months), 4 patients had died. The median follow-up was 18.50 months (5-49 months) for the surgery-only group (1/4 events, 25 %) and 24 months (2-34 months) for the chemo/radiotherapy group (3/4 events, 75 %). Survival time at 48 months for the overall population was 59 % (±0.11), while for the surgery-only group and the chemo/radiotherapy group was 90 % (±0.09) and 61 % (±0.34), respectively. In the univariate analysis, ADC values below or equal to 1.4 × 10(-3) mm(2)/s were associated with a negative prognosis both in the total population (P = 0.016) and in the surgery-only group (P < 0.001).
  
  
  CONCLUSIONS
  Despite the biggest limitation of our study (i.e. the small study population), we were able to show that pathological ADC could be considered a prognostic factor for oesophageal cancer. DWI might be introduced into clinical practice as a promising and reliable technique in the diagnostic pathway of this tumour.
authors.affiliation: Department of Radiology and Centre for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy. giganti.fra@gmail.com.
authors.forename: Francesco
authors.initials: F
authors.lastname: Giganti
authors.affiliation: Department of Radiology and Centre for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy.
authors.forename: Annalaura
authors.initials: A
authors.lastname: Salerno
authors.affiliation: Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ambrosi
authors.affiliation: Department of Surgery, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy.
authors.forename: Damiano
authors.initials: D
authors.lastname: Chiari
authors.affiliation: Department of Surgery, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Orsenigo
authors.affiliation: Department of Radiology and Centre for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Pathology Unit, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Albarello
authors.affiliation: Department of Oncology, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Mazza
authors.affiliation: Department of Surgery, San Raffaele Scientific Institute, Vita-Salute University, Milan, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Staudacher
authors.affiliation: Department of Radiology and Centre for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
authors.affiliation: Department of Radiology and Centre for Experimental Imaging, San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: De Cobelli
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D004938:Esophageal Neoplasms / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009942:Organometallic Compounds; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor; D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: Apparent diffusion coefficient; Diffusion-weighted magnetic resonance imaging; Neoadjuvant therapy; Oesophageal cancer; Prognosis; Surgery