title: Micrometastasis in colorectal cancer: does it affect staging?
abstract: BACKGROUND
  Micrometastasis (MM) in colorectal cancer (CRC) is not considered in tumour-node-metastasis (TNM) staging currently and also the prognostic significance of these occult tumoural cells is not proven yet. This study was designed to find whether MM to bone marrow (BM) and/or liver cause upstaging of the tumour according to conventional staging system and if it may alter the survival rate.
  
  
  METHODS
  Thirty-eight CRC patients who were candidates of surgical procedure were enrolled in our cross-sectional study. Liver and BM biopsy were obtained during the surgery to be looked for tissue-specific marker of CRC, CK20. CK20 expression in BM and liver was assessed by the two methods of reverse transcriptase polymerase chain reaction and immunohistochemistry.
  
  
  RESULTS
  Among the 38 submitted patients, a total number of 14 MM, including 10 BM (23%) and seven hepatic (18%) were detected. There was no significant difference in clinicopathological aspects including size, location, stage, grade, local invasion to vessels and neurons, TNM staging and relapse rate of tumour among patients with/without disseminated tumoural cells. The result did not demonstrate a survival difference between patients receiving neoadjuvant chemotherapy compared to other patients.
  
  
  CONCLUSIONS
  Our study did not confirm that the presence of MM influences TNM staging and overall survival of the patients. Additional clinical investigations with longer follow-up period and larger number of cases are required to decide on administration of neoadjuvant therapy in CRC patients.
authors.affiliation: Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Mohajeri
authors.affiliation: Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Kavak
authors.initials: K
authors.lastname: Hejab
authors.affiliation: Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran.|Immunology Department, Acquired Immunodeficiency Research Center, Isfahan, Iran.
authors.forename: Saba
authors.initials: S
authors.lastname: Sheikhbahaei
authors.affiliation: Department of Pathology, Sadoughi Hospital, Isfahan, Iran.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Mohajeri
authors.affiliation: Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Negar
authors.initials: N
authors.lastname: Niknam
authors.affiliation: Department of General Surgery, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mohammadi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019046:Bone Marrow Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D015179:Colorectal Neoplasms / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D053554:Keratin-20 / Q000378:metabolism; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D061206:Neoplasm Micrometastasis / Q000175:diagnosis*; D009367:Neoplasm Staging
chemical_list: C507499:KRT20 protein, human; D053554:Keratin-20
keywords: bone marrow; colorectal cancer; liver; micrometastasis; staging