title: Are there biological differences between screen-detected and interval colorectal cancers in the English Bowel Cancer Screening Programme?
abstract: We measured biomarkers of tumour growth and vascularity in interval and screen-detected colorectal cancers (CRCs) in the English Bowel Cancer Screening Programme in order to determine whether rapid tumour growth might contribute to interval CRC (a CRC diagnosed between a negative guaiac stool test and the next scheduled screening episode).
  
  
  
  Formalin-fixed, paraffin-embedded sections from 71 CRCs (screen-detected 43, interval 28) underwent immunohistochemistry for CD31 and Ki-67, in order to measure the microvessel density (MVD) and proliferation index (PI), respectively, as well as microsatellite instability (MSI) testing.
  
  
  
  Interval CRCs were larger (P=0.02) and were more likely to exhibit venous invasion (P=0.005) than screen-detected tumours. There was no significant difference in MVD or PI between interval and screen-detected CRCs. More interval CRCs displayed MSI-high (14%) compared with screen-detected tumours (5%). A significantly (P=0.005) higher proportion (51%) of screen-detected CRC resection specimens contained at least one polyp compared with interval CRC (18%) resections.
  
  
  
  We found no evidence of biological differences between interval and screen-detected CRCs, consistent with the low sensitivity of guaiac stool testing as the main driver of interval CRC. The contribution of synchronous adenomas to occult blood loss for screening requires further investigation.
authors.affiliation: Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, St James's University Hospital, Leeds LS9 7TF, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Walsh
authors.affiliation: South Tyneside NHS Foundation Trust, South Tyneside District Hospital, South Shields NE34 0PL, UK.|School of Medicine, Pharmacy and Health, University of Durham, Durham, UK.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Rees
authors.affiliation: South Tyneside NHS Foundation Trust, South Tyneside District Hospital, South Shields NE34 0PL, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Gill
authors.affiliation: South Tyneside NHS Foundation Trust, South Tyneside District Hospital, South Shields NE34 0PL, UK.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Parker
authors.affiliation: South Tyneside NHS Foundation Trust, South Tyneside District Hospital, South Shields NE34 0PL, UK.
authors.forename: Roisin
authors.initials: R
authors.lastname: Bevan
authors.affiliation: Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, St James's University Hospital, Leeds LS9 7TF, UK.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Perry
authors.affiliation: Newcastle upon Tyne Teaching Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Bury
authors.affiliation: Northumbria Healthcare NHS Foundation Trust, North Tyneside General Hospital, North Shields NE29 8NH, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Mills
authors.affiliation: Northumbria Healthcare NHS Foundation Trust, North Tyneside General Hospital, North Shields NE29 8NH, UK.
authors.forename: D Michael
authors.initials: DM
authors.lastname: Bradburn
authors.affiliation: School of Medicine, Pharmacy and Health, University of Durham, Durham, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Bramble
authors.affiliation: Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, St James's University Hospital, Leeds LS9 7TF, UK.|Centre for Digestive Diseases, St James's University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds LS9 7TF, UK.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hull
mesh_terms: D000368:Aged; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D004739:England; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D013997:Time Factors