RESUMO
Carcinoembryonic antigen (CEA) is not normally produced in significant quantities after birth but is elevated in colorectal cancer. The aim of this review was to define the current role of CEA and how best to investigate patients with elevated CEA levels. A systematic review of CEA was performed, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were identified from PubMed, Cochrane library, and controlled trials registers. We identified 2,712 papers of which 34 were relevant. Analysis of these papers found higher preoperative CEA levels were associated with advanced or metastatic disease and thus poorer prognosis. Postoperatively, failure of CEA to return to normal was found to be indicative of residual or recurrent disease. However, measurement of CEA levels alone was not sufficient to improve survival rates. Two algorithms are proposed to guide investigation of patients with elevated CEA: one for patients with elevated CEA after CRC resection, and another for patients with de novo elevated CEA. CEA measurement has an important role in the investigation, management and follow-up of patients with colorectal cancer.