title: Image cytometry accurately detects DNA ploidy abnormalities and predicts late relapse to high-grade dysplasia and adenocarcinoma in Barrett's oesophagus following photodynamic therapy.
abstract: OBJECTIVE
  DNA ploidy abnormalities (aneuploidy/tetraploidy) measured by flow cytometry (FC) are strong predictors of future cancer development in untreated Barrett's oesophagus, independent of histology grade. Image cytometric DNA analysis (ICDA) is an optical technique allowing visualisation of abnormal nuclei that may be undertaken on archival tissue. Our aim was to determine the accuracy of ICDA vs FC, and evaluate DNA ploidy as a prognostic biomarker after histologically successful treatment with photodynamic therapy (PDT).
  
  
  METHODS
  Nuclei were extracted from 40 mum sections of paraffin-embedded biopsies and processed for ICDA at UCL and FC at UW using standardised protocols. Subsequently, DNA ploidy was evaluated by ICDA on a cohort of 30 patients clear of dysplasia 1 year after aminolaevulinic acid PDT for high-grade dysplasia (HGD). The results were correlated with long-term outcome.
  
  
  RESULTS
  In the comparative study, 93% (41 out of 44) of cases were classified identically. Errors occurred in the near-diploid region by ICDA and the tetraploid region by FC. In the cohort study, there were 13 cases of late relapse (7 cancer, 6 HGD) and 17 patients who remained free of dysplasia after a mean follow-up of 44 months. Aneuploidy post-PDT was highly predictive for recurrent HGD or cancer with a hazard ratio of 8.2 (1.8-37.8) (log-rank P=0.001).
  
  
  CONCLUSIONS
  ICDA is accurate for the detection of DNA ploidy abnormalities when compared with FC. After histologically successful PDT, patients with residual aneuploidy are significantly more likely to develop HGD or cancer than those who become diploid. DNA ploidy by ICDA is a valuable prognostic biomarker after ablative therapy.
authors.affiliation: Department of Surgery, National Medical Laser Centre, University College London, 67-73 Riding House Street, London W1W 7EJ, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Dunn
authors.forename: G D
authors.initials: GD
authors.lastname: Mackenzie
authors.forename: D
authors.initials: D
authors.lastname: Oukrif
authors.forename: C A
authors.initials: CA
authors.lastname: Mosse
authors.forename: M R
authors.initials: MR
authors.lastname: Banks
authors.forename: S
authors.initials: S
authors.lastname: Thorpe
authors.forename: P
authors.initials: P
authors.lastname: Sasieni
authors.forename: S G
authors.initials: SG
authors.lastname: Bown
authors.forename: M R
authors.initials: MR
authors.lastname: Novelli
authors.forename: P S
authors.initials: PS
authors.lastname: Rabinovitch
authors.forename: L B
authors.initials: LB
authors.lastname: Lovat
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D000368:Aged; D001471:Barrett Esophagus / Q000175:diagnosis* / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D002869:Chromosome Aberrations; D020732:Cytogenetic Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D004947:Esophagus / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D006965:Hyperplasia / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics; D019044:Image Cytometry / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010778:Photochemotherapy / Q000379:methods; D011003:Ploidies; D011379:Prognosis; D012008:Recurrence; D013997:Time Factors
chemical_list: D004273:DNA, Neoplasm
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