title: Clinical parameters predicting pathologic tumor response after preoperative chemoradiotherapy for rectal cancer.
abstract: OBJECTIVE
  To identify pretreatment clinical parameters that could predict pathologic tumor response to preoperative chemoradiotherapy (CRT) for rectal cancer.
  
  
  METHODS
  The study involved 351 patients who underwent preoperative CRT followed by surgery between October 2001 and July 2006. Tumor responses to preoperative CRT were assessed in terms of tumor downstaging and tumor regression. Statistical analyses were performed to identify clinical factors associated with pathologic tumor response.
  
  
  RESULTS
  Tumor downstaging (defined as ypT2 or less) was observed in 167 patients (47.6%), whereas tumor regression (defined as Dworak's Regression Grades 3 or 4) was observed in 103 patients (29.3%) and complete regression in 51 patients (14.5%). Multivariate analysis found that predictors of downstaging were pretreatment hemoglobin level (p = 0.045), cN0 classification (p < 0.001), and serum carcinoembryonic antigen (CEA) level (p < 0.001), that predictors of tumor regression were cN0 classification (p = 0.044) and CEA level (p < 0.001), and that the predictor of complete regression was CEA level (p = 0.004).
  
  
  CONCLUSIONS
  The data suggest that pretreatment CEA level is the most important clinical predictor of pathologic tumor response. It may be of benefit in the selection of treatment options as well as the assessment of individual prognosis.
authors.affiliation: Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Yoon
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.forename: Kyung Hae
authors.initials: KH
authors.lastname: Jung
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Woong Sub
authors.initials: WS
authors.lastname: Koom
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Hyo Seong
authors.initials: HS
authors.lastname: Choi
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
authors.forename: Jae-Gahb
authors.initials: JG
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002272:Carcinoembryonic Antigen / Q000097:blood*; D003131:Combined Modality Therapy; D005260:Female; D006441:Hemoglobin A / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D012074:Remission Induction
chemical_list: D002272:Carcinoembryonic Antigen; D006441:Hemoglobin A