title: Classification of R1 resections for pancreatic cancer: the prognostic relevance of tumour involvement within 1 mm of a resection margin.
abstract: OBJECTIVE
  The current Royal College of Pathologists guidelines for pancreatoduodenectomy specimen reporting recommend that microscopic evidence of tumour within 1 mm of a resection margin (RM) should be classified as R1. No clinical evidence exists to justify this classification. The aim of this study was to identify the proportion of pancreatoduodenectomy specimens in which 'equivocal' RMs are present (tumour involvement within 1 mm of, but not directly reaching, one or more resection margins) and whether the survival of these patients was similar to that of patients with 'unequivocal' RM involvement.
  
  
  RESULTS
  Patients with histologically confirmed pancreatic ductal adenocarcinoma undergoing pancreatoduodenectomy between 1997 and 2007 (n = 163) were identified from a prospective database. One hundred and twenty-eight cases (79%) were classified as R1. Of these, 57 (45% of all R1 cases) were based on 'equivocal' margin involvement. There was no significant difference in overall survival between equivocal and unequivocal R1 resections (log rank, P = 0.102). All R1 resections had a poorer survival on univariate (log rank, P = 0.013), but not multivariate, analysis (Cox, P = 0.132).
  
  
  CONCLUSIONS
  Our results indicate that cases with microscopic tumour involvement within 1 mm of a resection margin should be considered synonymous with incomplete excision for resected pancreatic cancer.
authors.affiliation: Department of Pathology, School of Cancer Studies, University of Liverpool, Royal Liverpool University Hospital, , 5th Floor Duncan Building, Daulby Street, Liverpool L69 3GA, UK. f.campbell@liv.ac.uk
authors.forename: Fiona
authors.initials: F
authors.lastname: Campbell
authors.forename: Richard A
authors.initials: RA
authors.lastname: Smith
authors.forename: Philip
authors.initials: P
authors.lastname: Whelan
authors.forename: Robert
authors.initials: R
authors.lastname: Sutton
authors.forename: Michael
authors.initials: M
authors.lastname: Raraty
authors.forename: John P
authors.initials: JP
authors.lastname: Neoptolemos
authors.forename: Paula
authors.initials: P
authors.lastname: Ghaneh
mesh_terms: D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D009664:Norway / Q000453:epidemiology; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D016577:Pancreaticoduodenectomy; D011379:Prognosis; D015996:Survival Rate