Evaluation of tumor markers: An evidence-based guide for determination of clinical utility

Abstract

A tumor marker is clinically useful if its results serve to separate a large heterogeneous population into smaller populations with more precisely predictable outcomes. In theory, if this separation is both reliable and disparate, one can apply therapy more efficiently to the population by exposing those most likely to need and benefit from the therapy while ensuring that the other group avoids needless toxicities. In essence, the term tumor marker has come to describe a variety of molecules or processes that differ from the norm in either malignant cells, tissues, or fluids in patients with malignancies. Assessing these alterations from normal can be used to place patients into categories that are distinguished by different outcomes, either in the absence of specific therapy or after various treatments are applied. © 2006 Springer Science+Business Media, Inc.