title: The role of carcinoembriogenic antigen in predicting response and survival to neoadjuvant chemoradiotherapy for distal rectal cancer.
abstract: OBJECTIVE
  Carcinoembriogenic antigen (CEA) is the most frequently used tumor marker in rectal cancer. A decrease in carcinoembriogenic antigen after radical surgery is associated with survival in these patients. Neoadjuvant chemoradiotherapy may lead to significant primary tumor downstaging, including complete tumor regression in selected patients. Therefore, we hypothesized that a decrease in CEA after neoadjuvant chemoradiotherapy could reflect tumor response to chemoradiotherapy, affecting final disease stage and ultimately survival.
  
  
  METHODS
  Patients with distal rectal cancer managed by neoadjuvant chemoradiotherapy and available pretreatment and postchemoradiotherapy levels of CEA were eligible for the study. Outcomes studied included final disease stage, relapse, and survival, and these were compared according to initial CEA level, post-chemoradiotherapy CEA level, and the reduction in CEA.
  
  
  RESULTS
  Overall 170 patients were included. Post-chemoradiotherapy CEA levels <5 ng/ml were associated with increased rates of complete clinical response and pathologic response. Additionally, postchemoradiotherapy CEA levels <5 ng/ml were associated with increased overall and disease-free survival (P = 0.01 and P = 0.03). There was no correlation between initial CEA level or reduction in CEA and complete response or survival.
  
  
  CONCLUSIONS
  A postchemoradiotherapy CEA level <5 ng/ml is a favorable prognostic factor for rectal cancer and is associated with increased rates of earlier disease staging and complete tumor regression. Postchemoradiotherapy CEA levels may be useful in decision making for patients who may be candidates for alterative treatment strategies.
authors: Colorectal Surgery Division, University of São Paulo School of Medicine, Sao Paulo, Brazil. rodrigo.operez@gmail.com
authors: Rodrigo O
authors: RO
authors: Perez
authors: Guilherme P
authors: GP
authors: São Julião
authors: Angelita
authors: A
authors: Habr-Gama
authors: Desidério
authors: D
authors: Kiss
authors: Igor
authors: I
authors: Proscurshim
authors: Fabio Guilherme
authors: FG
authors: Campos
authors: Joaquim J
authors: JJ
authors: Gama-Rodrigues
authors: Ivan
authors: I
authors: Cecconello
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D002272:Carcinoembryonic Antigen / Q000378:metabolism*; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen