title: Increased lymph node retrieval decreases adjuvant chemotherapy rate for stage II colon cancer.
abstract: OBJECTIVE
  Investigation of lymph nodes in colorectal specimens after surgery due to cancer is important for staging the cancer. There has to be an adequate number of lymph nodes to conclude a node-negative status. Our aim was to investigate if change in fixative could give increased lymph node yield, and if this could result in a potential decrease of adjuvant treatment for stage II patients. In addition, we wanted to evaluate if the change in fixative could potentially affect subsequent molecular testing.
  
  
  METHODS
  All resection specimens from one hospital were from 2011 fixed in GEWF while resection specimens from two other hospitals were fixed in conventional buffered formalin. Number of lymph nodes harvested were compared from two periods; 2009/2010 and 2012/2013. In addition, tumors fixed in GEWF and tumors fixed in formalin were tested separately with immunohistochemical staining and molecular testing.
  
  
  RESULTS
  There was a significant increase in lymph node retrieval in specimens fixed in GEWF compared to number of lymph nodes found before the implementation of this fixative (p < 0.001). For hospitals using only formalin, the number of nodes did not increase significantly. Number of positive lymph nodes did not increase. Immunohistochemical staining can be a problem with tumors fixed in GEWF, but DNA quality seems not affected by the changes.
  
  
  CONCLUSIONS
  GEWF enhances lymph node detection in colorectal cancer specimens, leading to fewer patients being falsely defined as high-risk stage II. The loss of stability when staining for MMR-proteins can be overcome by molecular analysis when needed.
authors.affiliation: a Department of Gastrointestinal Surgery , University Hospital of North Norway , Tromsø , Norway ;|b Department of Clinical Medicine, Faculty of Health Sciences , UiT The Arctic University of Norway , Tromsø , Norway ;
authors.forename: Stig
authors.initials: S
authors.lastname: Norderval
authors.affiliation: c Department of Clinical Pathology , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Ørjan B
authors.initials: ØB
authors.lastname: Solstad
authors.affiliation: a Department of Gastrointestinal Surgery , University Hospital of North Norway , Tromsø , Norway ;
authors.forename: Mia
authors.initials: M
authors.lastname: Hermansen
authors.affiliation: c Department of Clinical Pathology , University Hospital of North Norway , Tromsø , Norway ;|d Department of Medical Biology, Faculty of Health Sciences , UiT The Arctic University of Norway , Tromsø , Norway.
authors.forename: Sonja E
authors.initials: SE
authors.lastname: Steigen
mesh_terms: D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D004247:DNA / Q000032:analysis; D005404:Fixatives / Q000494:pharmacology*; D005557:Formaldehyde / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000473:pathology*; D009367:Neoplasm Staging; D012189:Retrospective Studies
chemical_list: D005404:Fixatives; D005557:Formaldehyde; D004247:DNA
keywords: Colon cancer; fixative; lymph node; staging