title: The role of pre-treatment diffusion-weighted MRI in predicting long-term outcome of colorectal liver metastasis.
abstract: OBJECTIVE
  To determine the prognostic value of pre-treatment apparent diffusion coefficient (ADC) of colorectal liver metastases in predicting disease response, progression-free survival (PFS) and overall survival (OS).
  
  
  METHODS
  We retrospectively reviewed 102 patients who underwent pre-treatment diffusion-weighted MRI using a breath-hold (b=0, 150, 500) or a free-breathing (b=0, 50, 100, 250, 500, 750) technique. The mean ADC (b=0-500) and mean flow-insensitive ADC (ADChigh) values (breath-hold: b=150 and 500; free-breathing: b=100 and 500) of up to three hepatic lesions were evaluated in each patient. Clinical and laboratory parameters were recorded. Tumour response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) criteria at 12 weeks after treatment. Associations between tumour response, ADC values and clinical/laboratory parameters were examined by one-way analysis of variance. The relationship of ADC with PFS and OS was determined by Kaplan-Meier analysis.
  
  
  RESULTS
  62 patients responded to chemotherapy at 12 weeks. The pre-treatment mean ADC and mean ADChigh were higher in the non-responding group than in the responding group (1.55 vs 1.36, p=0.033; 1.40 vs 1.16, p=0.024). However, the PFS and OS of the two groups of patients stratified by the median of mean ADC values or threshold derived by receiver operating characteristic analysis were not statistically significant. By multivariate Cox regression analysis, patients with ≤2 metastases and response to chemotherapy showed better PFS; white cell count ≤10 and surgical treatment were associated with better OS.
  
  
  CONCLUSIONS
  Colorectal liver metastasis with higher pre-treatment mean ADC and mean ADChigh was associated with poorer response to chemotherapy. However, ADC and ADChigh values did not predict the patient outcome in this study cohort.
  
  
  CONCLUSIONS
  High mean ADC values of colorectal liver metastases on pre-treatment diffusion-weighted MRI is associated with poorer response to chemotherapy.
authors.affiliation: Department of Radiology, Royal Marsden Hospital, Sutton, UK. henrytam01@gmail.com
authors.forename: H H
authors.initials: HH
authors.lastname: Tam
authors.forename: D J
authors.initials: DJ
authors.lastname: Collins
authors.forename: G
authors.initials: G
authors.lastname: Brown
authors.forename: I
authors.initials: I
authors.lastname: Chau
authors.forename: D
authors.initials: D
authors.lastname: Cunningham
authors.forename: M O
authors.initials: MO
authors.lastname: Leach
authors.forename: D-M
authors.initials: DM
authors.lastname: Koh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000401:mortality / Q000473:pathology* / Q000556:secondary* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D016019:Survival Analysis