TUMOR-MARKERS - CURRENT STATUS AND FUTURE APPLICATIONS

A variety of tumour marker tests are available for three major intende d uses: screening, diagnosis, and monitoring. For each use, performanc e characteristics need to be well established. The value of a marker d epends heavily on two predominant performance parameters - sensitivity and specificity. These parameters must be established with respect to the intended clinical use of the marker. Therefore, it is important t o balance the analytical/clinical sensitivity and the resultant claims for the test. The FDA review and evaluation of a tumour marker test f ocuses upon the intended use and the clinical utility of the marker. T he sponsor must prove all specific claims. The data must support well- designed scientific protocols and clinical studies[1]. Generally, a tu mour marker test is evaluated based on its intended clinical use, epid emiological sensitivity, specificity, and prevalence. A particular tum our marker test will have higher predictive value when it is applied t o a population with a higher prevalence of the type of cancer being st udied. Clinical utility for screening use may be limited by low preval ence [2].