title: Usefulness of serum carcinoembryonic antigen (CEA) in evaluating response to chemotherapy in patients with advanced non small-cell lung cancer: a prospective cohort study.
abstract: BACKGROUND
  High serum carcinoembryonic antigen (CEA) levels are an independent prognostic factor for recurrence and survival in patients with non-small cell lung cancer (NSCLC). Its role as a predictive marker of treatment response has not been widely characterized.
  
  
  METHODS
  180 patients with advanced NSCLC (stage IIIB or Stage IV), who had an elevated CEA serum level (>10 ng/ml) at baseline and who had no more than one previous chemotherapy regimen, were included. CEA levels were measured after two treatment cycles of platinum based chemotherapy (93%) or a tyrosine kinase inhibitor (7%). We evaluate the change in serum CEA levels and the association with response measured by RECIST criteria.
  
  
  RESULTS
  After two chemotherapy cycles, the patients who achieved an objective response (OR, 28.3%) had a reduction of CEA levels of 55.6% (95%CI [box drawings light horizontal]64.3 to [box drawings light horizontal]46.8) compared to its basal level, with an area under the ROC curve (AURC) of 0.945 (95%CI 0.91-0.99), and a sensitivity and specificity of 90.2 and 89.9%, respectively, for a CEA reduction of ≥14%. Patients that achieved a decrease in CEA levels ≥14% presented an overall response in 78% of cases, stable disease in 20.3% and progression in 1.7%, while patients that did not attain a reduction ≥14% had an overall response of 4.1%, stable disease of 63.6% and progression of 32.2% (p < 0.001). Patients with stable (49.4%) and progressive disease (22.2%) had an increase of CEA levels of 9.4% (95%CI 1.5-17.3) and 87.5% (95%CI 60.9-114) from baseline, respectively (p < 0.001). The AURC for progressive disease was 0.911 (95%CI 0.86-0.961), with sensitivity and specificity of 85 and 15%, respectively, for a CEA increase of ≥18%. PFS was longer in patients with a ≥14% reduction in CEA (8.7 vs. 5.1 months, p < 0.001). Neither reduction of CEA nor OR were predictive of OS.
  
  
  CONCLUSIONS
  A CEA level reduction is a sensitive and specific marker of OR, as well as a sensitive indicator for progression to chemotherapy in patients with advanced NSCLC who had an elevated CEA at baseline and had received no more than one chemotherapy regimen. A 14% decrease in CEA levels is associated with a better PFS.
authors.forename: Oscar
authors.initials: O
authors.lastname: Arrieta
authors.forename: Cynthia
authors.initials: C
authors.lastname: Villarreal-Garza
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Barrera
authors.forename: Marcelino
authors.initials: M
authors.lastname: Morales
authors.forename: Yuzmiren
authors.initials: Y
authors.lastname: Dorantes-Gallareta
authors.forename: Omar
authors.initials: O
authors.lastname: Peña-Curiel
authors.forename: Susana
authors.initials: S
authors.lastname: Contreras-Reyes
authors.forename: Eleazar Omar
authors.initials: EO
authors.lastname: Macedo-Pérez
authors.forename: Jorge
authors.initials: J
authors.lastname: Alatorre-Alexander
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen / Q000097:blood*; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen