title: Cytokeratin staining for complete remission in rectal cancer after chemoradiation.
abstract: OBJECTIVE
  Pathologic complete remission (CR) of rectal cancer after neoadjuvant chemoradiation therapy (CRT) is generally confirmed by routine hematoxylin and eosin (H&E) staining. The aim of this study was to identify residual rectal cancer cells in primary lesions of patients with pathologic CR by immunohistochemical staining for cytokeratin.
  
  
  METHODS
  The medical records of 358 rectal cancer patients who underwent neoadjuvant CRT prior to radical surgery between October 2002 and August 2007 were reviewed. The authors stained sections of resected specimens of 58 patients (15.9%; 42 males; mean age 54 years) who achieved pathologic CR (as determined originally by H&E staining) with H&E and performed immunohistochemistry (IHC) using monoclonal anti-cytokeratin antibody. These stained sections were reviewed for residual rectal cancer cells by a pathologist.
  
  
  RESULTS
  Of the 58 patients that achieved CR by initial pathologic examinations, eight (13.8%) were found to contain tumor by cytokeratin IHC. H&E staining revealed that six of these were positive for cancer cells, but the remaining two were negative for residual rectal cancer cells.
  
  
  CONCLUSIONS
  Through better identification of residual rectal cancer cells, cytokeratin IHC offers a means of improving staging accuracy and thus provides useful information for prognosis and treatment decisions for patients with rectal cancer who had a clinical CR after CRT.
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, Seoul, South Korea.
authors.forename: Hae Ran
authors.initials: HR
authors.lastname: Yun
authors.forename: Hee Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Seok Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Seong Hyeon
authors.initials: SH
authors.lastname: Yun
authors.forename: Woo Yong
authors.initials: WY
authors.lastname: Lee
authors.forename: Yong Beom
authors.initials: YB
authors.lastname: Cho
authors.forename: Hee Jeong
authors.initials: HJ
authors.lastname: Shin
authors.forename: Ho-Kyung
authors.initials: HK
authors.lastname: Chun
mesh_terms: D003710:Demography; D005260:Female; D006801:Humans; D007633:Keratins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000473:pathology; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D012074:Remission Induction; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D007633:Keratins