The FDA's perspective on the evaluation of tumor marker tests.

Cancer marker tests are often proposed for three intended uses: screening, diagnosis, and monitoring. For each intended use, performance characteristics need to be well defined. The utility of a marker in a given setting depends heavily on two predominant performance characteristics--sensitivity and specificity. These parameters must be established with respect to the intended clinical use of the marker. The value of the marker in a particular situation also depends on the effectiveness of therapy for the malignancy. In reviewing a cancer marker test, the US Food and Drug Administration focuses on both the proposed intended use statement and the clinical utility of the marker. The sponsor is expected to provide specific claims data in support of the safety and effectiveness of the device through well-designed and -executed clinical studies. Several cancer markers are already available. In the future, new markers are anticipated that may greatly expand the range of usefulness in cancer diagnosis screening and monitoring.