Tumor markers in finding recurrent disease in colorectal cancer: a diagnostic review

Aim: In the search for evidence-based follow-up of patients after resection for colorectal cancer, numerous tumor markers have been proposed. This review has evaluated these markers and comments on the diagnostic accuracy in finding recurrent disease in relation to Carcino-Embryonic Antigen (CEA). Methods: A comprehensive literature review (1985-2010) was performed by two independent reviewers. Sensitivity and specificity of markers mentioned in the articles were checked by recalculation. A validated quality score system was used to estimate study quality. Results: Seventeen studies focusing on eight different markers were included. Three markers were shown to have comparable or better accuracy than CEA: TPA, CA 242 and CA 72-4 in at least one study. These three markers, from four independent studies, showed a tumor marker sensitivity of > 60% in combination with an outperformance of CEA in follow-up. These results were not confirmed by six other studies investigating the same markers. Conclusion: This review revealed three tumor markers other than CEA that have been shown to adequately indicate recurrences in colorectal cancer. However, comparability of studies was difficult. Therefore a prospective study of these markers seems necessary to investigate their real value, and to overcome design and inclusion biases.