title: CEA - a predictor for pathologic complete response after neoadjuvant therapy for rectal cancer.
abstract: BACKGROUND
  Preoperative chemoradiation therapy in patients with rectal cancer results in pathologic complete response in approximately 10% to 30% of patients. Accurate predictive factors for obtaining pathologic complete response would likely influence the selection of patients best treated by chemoradiation therapy as the primary treatment without radical surgery.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the impact of tumor size, stage, location, circumferential extent, patient characteristics, and pretreatment CEA levels on the development of pathologic complete response after chemoradiation therapy.
  
  
  METHODS
  This study is a retrospective review.
  
  
  METHODS
  Five hundred thirty patients treated with preoperative chemoradiation therapy and radical surgery for rectal adenocarcinoma between 1998 and 2011 were identified. A total of 469 patients remained after excluding patients with a history of pelvic radiation (n = 2), previous transanal endoscopic microsurgery or polypectomy of the primary lesion (n = 15), concurrent malignant tumor (n = 14), and no information about pre- or posttreatment T stage in the chart (n = 30). Preoperative CEA levels were available for 267 patients (57%).
  
  
  METHODS
  Preoperative chemoradiation therapy and total mesorectal excision were performed in patients with rectal cancer.
  
  
  RESULTS
  The primary outcome measured was pathologic complete response.
  
  
  RESULTS
  : Ninety-six patients (20%) were found to have a pathologic complete response in the operative specimen. Low pretreatment CEA (3.4 vs 9.6 ng/mL; p = 0.008) and smaller mean tumor size (4.2 vs 4.7 cm; p = 0.02) were significantly associated with pathologic complete response. Low CEA levels and interruption in chemoradiation therapy were significant predictors of pathologic complete response in the multivariate analysis. When stratifying for smoking status, low CEA level was significantly associated with pathologic complete response only in the group of nonsmokers (p = 0.02).
  
  
  CONCLUSIONS
  This study was limited by its retrospective design, missing CEA values, and lack of tumor regression grade assessment.
  
  
  CONCLUSIONS
  We demonstrated an association between low pretreatment CEA levels, interruption in chemoradiation therapy, and pathologic complete response in patients treated with neoadjuvant chemoradiation therapy for locally advanced rectal cancer. The predictive value of CEA in smokers can be limited, and further studies are needed to evaluate the impact of smoking on the predictive value of CEA levels for pathologic complete response in rectal cancer.
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, University of Minnesota, Minneapolis, Minnesota 52242, USA. ulrik-wallin@uiowa.edu
authors.forename: Ulrik
authors.initials: U
authors.lastname: Wallin
authors.forename: David
authors.initials: D
authors.lastname: Rothenberger
authors.forename: Ann
authors.initials: A
authors.lastname: Lowry
authors.forename: Russell
authors.initials: R
authors.lastname: Luepker
authors.forename: Anders
authors.initials: A
authors.lastname: Mellgren
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology / Q000628:therapy*; D014408:Biomarkers, Tumor / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood*; D059248:Chemoradiotherapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D057234:Preoperative Period; D011351:Proctoscopy / Q000379:methods*; D011379:Prognosis; D012004:Rectal Neoplasms / Q000097:blood / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen