Purpose: The primary objective was to determine clinical practice guidelines for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of breast and colorectal cancers. These guidelines are intended for use in the care of patients outside of clinical trials.
Methods: Six tumor markers for colorectal cancer and seven for breast cancer were considered. They could be recommended or not for routine use or for special circumstances. In general, the significant health outcomes identified for use in making clinical practice guidelines (overall survival, disease-free survival, quality of life, lesser toxicity, and cost-effectiveness) were used when data were available. Expert consensus was used to inform the recommendations for use of tumor markers when published evidence was insufficient. A computerized literature search was performed using Medline. In addition to reports collected by individual panel members, all articles published in the English-speaking literature from January 1989 to April 1994 were collected for review and distributed to all members of the Panel. Values for use, utility, and levels of evidence were assigned by the expert reviewers and approved by the Panel. Tumor markers were assigned benefit if they had prognostic or predictive value that would lead to the favorable outcomes listed above. Harms considered were inappropriate disease management, and excess cost without definable benefit. Costs were considered but were never the sole determinant of a recommendation.
Results and conclusion: For colorectal cancer, it is recommended that carcinoembryonic antigen (CEA) levels be measured preoperatively if it would change surgical management. It is recommended that CEA levels be monitored every 2 to 3 months for > or = 2 years, if resection of liver metastasis would be clinically indicated. The data are insufficient to recommend the routine use of lipid-associated sialic acid (LASA), CA 19-9, DNA index, DNA flow cytometric proliferation analysis, p53 tumor suppressor gene, and ras oncogene. For breast cancer, estrogen receptor and progesterone receptor are recommended to be measured on every primary specimen, but on subsequent specimens only if it would lead to a change in management. The data are insufficient to recommend the routine use of DNA index, DNA flow cytometric proliferation analysis, CA 15-3, CEA, c-erbB-2, p53 or cathepsin-D. In the absence of readily measurable disease, CA 15-3 and CEA levels can be used to document treatment failure. New markers and new evidence will be evaluated by annual update of these guidelines.