title: Carcinoembryonic antigen as a predictor of pathologic response and a prognostic factor in locally advanced rectal cancer patients treated with preoperative chemoradiotherapy and surgery.
abstract: OBJECTIVE
  To evaluate the role of serum carcinoembryonic antigen (CEA) as a predictor of response to preoperative chemoradiotherapy (CRT) and prognostic factor for rectal cancer.
  
  
  METHODS
  The study retrospectively evaluated 352 locally advanced rectal cancer patients who underwent preoperative CRT followed by surgery. Serum CEA levels were determined before CRT administration (pre-CRT CEA) and before surgery (post-CRT CEA). Correlations between pre-CRT CEA levels and rates of good response (Tumor regression grade 3/4) were explored. Patients were categorized into three CEA groups according to their pre-/post-CRT CEA levels (ng/mL) (Group A: pre-CRT CEA <or= 3; B: pre-CRT CEA >3, post-CRT CEA <or=3; C: pre- and post-CRT CEA >3 ng/mL), and their oncologic outcomes were compared.
  
  
  RESULTS
  Of 352 patients, good responses were achieved in 94 patients (26.7%). The rates of good response decreased significantly as the pre-CRT CEA levels became more elevated (CEA [ng/mL]: <or=3, 36.4%; 3-6, 23.6%; 6-9, 15.6%; >9, 7.8%; p < 0.001). The rates of good response were significantly higher in Group A than in Groups B and C (36.4% vs. 17.3% and 14.3%, respectively; p < 0.001). The 3-year disease-free survival rate was significantly better in Groups A and B than in Group C (82% and 79% vs. 57%, respectively; p = 0.005); the CEA grouping was identified as an independent prognostic factor (p = 0.025).
  
  
  CONCLUSIONS
  In locally advanced rectal cancer patients, CEA levels could be of clinical value as a predictor of response to preoperative CRT and as an independent prognostic factor after preoperative CRT and curative surgery.
authors.affiliation: Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Republic of Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Park
authors.forename: Seok-Byung
authors.initials: SB
authors.lastname: Lim
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.forename: Kyung Hae
authors.initials: KH
authors.lastname: Jung
authors.forename: Yong Sang
authors.initials: YS
authors.lastname: Hong
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Chang
authors.forename: Hyo Seong
authors.initials: HS
authors.lastname: Choi
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
mesh_terms: D000230:Adenocarcinoma / Q000097:blood* / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002272:Carcinoembryonic Antigen / Q000097:blood*; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011379:Prognosis; D012004:Rectal Neoplasms / Q000097:blood* / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D002272:Carcinoembryonic Antigen