title: Carbohydrate antigen 19-9 levels associated with pathological responses to preoperative chemoradiotherapy in rectal cancer.
abstract: OBJECTIVE
  To investigate whether pretreatment serum carbohydrate antigen 19-9 (CA 19-9) levels are associated with pathological responses to preoperative chemoradiotherapy (CRT) in patients with rectal cancer.
  
  
  METHODS
  In total, 260 patients with locally advanced rectal cancer (cT3-4NanyM0) who underwent preoperative CRT and radical surgery were analyzed retrospectively. CRT consisted of 50.4 Gy pelvic radiotherapy and concurrent chemotherapy. Radical surgery was performed at a median of 7 weeks after CRT completion. Pathological CRT response criteria included downstaging (ypStage 0-I) and ypT0-1. A discrimination threshold of CA 19-9 level was determined using a receiver operating characteristics analysis.
  
  
  RESULTS
  The median CA 19-9 level was 8.0 (1.0-648.0) U/mL. Downstaging occurred in 94 (36.2%) patients and ypT0-1 in 50 (19.2%). The calculated optimal threshold CA 19-9 level was 10.2 U/mL for downstaging and 9.0 U/mL for ypT0-1. On multivariate analysis, CA 19-9 (≤ 9.0 U/mL) was significantly associated with downstaging (odds ratio, 2.089; 95% confidence interval, 1.189-3.669; P=0.010) or ypT0-1 (OR, 2.207; 95%CI, 1.079-4.512; P=0.030), independent of clinical stage or carcinoembryonic antigen.
  
  
  CONCLUSIONS
  This study firstly showed a significant association of pretreatment serum CA 19-9 levels with pathological CRT responses of rectal cancer. The CA 19-9 level is suggested to be valuable in predicting CRT responses of rectal cancer cases before treatment.
authors.affiliation: Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea E-mail : radiopiakim@hanmail.net.
authors.forename: Seung-Gu
authors.initials: SG
authors.lastname: Yeo
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Tae Hyun
authors.initials: TH
authors.lastname: Kim
authors.forename: Sun Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Baek
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Park
authors.forename: Jae Hwan
authors.initials: JH
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018395:CA-19-9 Antigen / Q000097:blood*; D002241:Carbohydrates / Q000097:blood*; D059248:Chemoradiotherapy / Q000379:methods; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D011300:Preoperative Care; D012004:Rectal Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents; D018395:CA-19-9 Antigen; D002241:Carbohydrates