title: Tumor budding is a strong and reproducible prognostic marker in T3N0 colorectal cancer.
abstract: BACKGROUND
  Tumor budding along the advancing front of colorectal adenocarcinoma is an early event in the metastatic process. A reproducible, prognostic budding scoring system based on outcomes in early stage colorectal cancer has not been established.
  
  
  METHODS
  One hundred twenty-eight T3N0M0 colorectal carcinoma patients with known outcome were identified. Tumor budding was defined as isolated tumor cells or clusters of <5 cells at the invasive tumor front. Tumor bud counts were generated in 5 regions at 200x by 2 pathologists (conventional bud count method). The median bud count per case was used to divide cases into low (median=0) and high budding (median > or =1) groups. Forty cases were reevaluated to assess reproducibility using the conventional and a novel rapid bud count method.
  
  
  RESULTS
  Fifty-seven (45%) carcinomas had high and 71 (55%) had low budding scores. High budding was associated with an infiltrative growth pattern (P<0.0001) and lymphovascular invasion (P=0.005). Five-year cancer-specific survival was significantly poorer in high compared with low budding groups: 63% versus 91%, respectively, P<0.0001. Multivariate analysis demonstrated tumor budding to be independently prognostic (hazard ratio=4.76, P<0.001). Interobserver agreement was at least equivalent comparing the conventional to the rapid bud count methods: 87.5% agreement (kappa=0.75) versus 92.5% agreement (kappa=0.85), respectively.
  
  
  CONCLUSIONS
  Tumor budding is a strong, reproducible, and independent prognostic marker of outcome that is easily assessed on hematoxylin and eosin slides. This may be useful for identifying the subset of T3N0M0 patients at high risk of recurrence who may benefit from adjuvant therapy.
authors.affiliation: Department of Histopathology & Centre for Colorectal Disease, St Vincent's University Hospital, Dublin, Ireland.
authors.forename: Lai Mun
authors.initials: LM
authors.lastname: Wang
authors.forename: David
authors.initials: D
authors.lastname: Kevans
authors.forename: Hugh
authors.initials: H
authors.lastname: Mulcahy
authors.forename: Jacintha
authors.initials: J
authors.lastname: O'Sullivan
authors.forename: David
authors.initials: D
authors.lastname: Fennelly
authors.forename: John
authors.initials: J
authors.lastname: Hyland
authors.forename: Diarmuid
authors.initials: D
authors.lastname: O'Donoghue
authors.forename: Kieran
authors.initials: K
authors.lastname: Sheahan
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D003584:Cytological Techniques / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D011379:Prognosis