title: The concurrence of histologically positive resection margins and sessile morphology is an important risk factor for lymph node metastasis after complete endoscopic removal of malignant colorectal polyps.
abstract: BACKGROUND
  The optimal procedure to be followed after colonoscopic polypectomy of malignant colorectal polyps with nontumour-free resection margins at histology is a matter of controversy. While some authors recommend merely local or segmental follow-up resection, others favour an oncological resection.
  
  
  METHODS
  One hundred five patients, each with a single malignant polyp, were investigated. Patients with a macroscopically evident malignant polyp and those in whom the endoscopist reported incomplete polypectomy were excluded from the study.
  
  
  RESULTS
  Postpolypectomy morbidity was 4%, and postoperative was 14%. In only 39 cases were the resection margins adjudged to be tumour-free. Histology following subsequent surgery or the follow-up examinations revealed a local recurrence or residual carcinoma at the polypectomy site in only three (2.8%) cases and lymph node metastasis in eight (7.6%) cases. Five patients had remnant adenoma at the polypectomy site. Of the high-risk factors, histological incomplete removal (n = 66, p = 0.04, odds ratio (OR) 10.2) and lymph vessel infiltration (n = 7, p = 0.02, OR 9.2) revealed a significant correlation with lymph node metastasis, but not with remnant tumour. In the case of sessile polyp, the assessment of histological incomplete removal was highly significantly correlated with lymph node metastasis (n = 55, p = 0.007, OR 18.1).
  
  
  CONCLUSIONS
  Polypectomy artefacts appear to be responsible for the discrepancy between histology and the tumour remnants actually present. On the other hand, histologically incompletely removed sessile malignant polyps represent an appreciably higher risk for lymph node metastasis. Such cases should, therefore, be submitted to further oncological resection.
authors.affiliation: Department of General, Visceral, Vascular & Paediatric Surgery, University Hospital Wuerzburg, 97078 Wuerzburg, Germany. Boenicke_L@chirurgie.uni-wuerzburg.de
authors.forename: Lars
authors.initials: L
authors.lastname: Boenicke
authors.forename: Martin
authors.initials: M
authors.lastname: Fein
authors.forename: Marco
authors.initials: M
authors.lastname: Sailer
authors.forename: Christoph
authors.initials: C
authors.lastname: Isbert
authors.forename: Christoph-Tomas
authors.initials: CT
authors.lastname: Germer
authors.forename: Andreas
authors.initials: A
authors.lastname: Thalheimer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000473:pathology* / Q000601:surgery; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D004724:Endoscopy; D005260:Female; D006801:Humans; D008198:Lymph Nodes; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors