Practice guidelines for tumor marker use in the clinic.

BACKGROUND Increasing interest in implementing the practice of evidence-based medicine in oncology has encouraged the development of clinical guidelines, many of which include recommendations about the appropriate use of serum tumor markers. METHODS Recent national and international guidelines relating to the use of tumor markers in germ cell, colorectal, breast, ovarian, prostate, lung, neuroendocrine, and thyroid cancers were identified from the scientific literature and other sources and tabulated. RESULTS Guideline recommendations developed by national and international groups and relating to the use of tumor markers for specific cancers are reviewed and compared, considering the recommendations made for their use in screening, diagnosis, prognosis, and monitoring of therapy. Potential advantages and disadvantages of clinical guidelines, how best to implement them, and means of auditing their effectiveness are also considered. CONCLUSIONS Excellent clinical guidelines, including recommendations for the most appropriate use of tumor markers, are already available for many cancers. Many questions relating to optimal use of these important tests remain to be answered, but current guidelines already contain much valuable information and advice. Further dissemination and implementation of the guidelines should encourage better use of tumor markers in clinical practice. Careful audit studies are also required to establish the impact of these guidelines on the practice of evidence-based medicine.