Defining Clinical Utility of Tumor Biomarker Tests: A Clinician's Viewpoint.

Tumor biomarker tests (TBTs) are used to guide therapeutic strategies for patients with cancer. However, the regulatory environment for TBTs in the United States is inconsistent and, in general, TBTs are poorly valued. The National Academy of Medicine has recommended that TBTs should not be used in general practice until they are shown to have analytical validity and clinical utility. The latter term, first coined by the Evaluation of Genomic Applications in Practice and Prevention Initiative, has been widely stated but is indeterminately defined. In considering whether a TBT has clinical utility, several factors need to be considered: (1) What is the intended use of the TBT? (2) What are the end points that are used to determine clinical utility? (3) How substantial does the difference in end points between groups defined by the TBT need to be to determine therapeutic strategies? (4) What is the risk tolerance of the stakeholders? and (5) Who are the stakeholders that make the decision? For all these factors, the data used to consider clinical utility must be derived from level I evidence studies. In conclusion, there is no strict definition of clinical utility for a TBT. However, consideration of these factors will lead to more objective conclusions. Doing so will facilitate value-based decisions regarding whether a TBT should be used to guide patient care.