Tumour Markers in the Diagnosis and Management of Patients with Hepatocellular Carcinoma

Abstract

It is important to recognise from the outset that the criteria on which the value of a tumour marker is based are quite different in respect of diagnosis and management. In this context we mean by management monitoring of response to therapy. With regards diagnosis we are concerned about the specificity and sensitivity of the marker whereas in monitoring therapy the diagnosis has been established and the main requirement of a tumour marker is only that it should be quantitatively related to the viable tumour cell mass. The second concept which is often overlooked is that the value of a marker must be assessed in the appropriate clinical setting. Thus, in the case of hepatocellular carcinoma (HCC), if our putative marker is positive in acute viral hepatitis as well as in HCC, it is of little consequence as there is no difficulty in clinical practice in distinguishing between these two conditions. On the other hand if our marker was also positive in uncomplicated cirrhosis, a condition which it is important and otherwise difficult to distinguish from HCC, the value of the marker would be severely limited. It must also be remembered that a marker which appears very specific having, say, a false-positive rate of 1:100 may still be of limited value if the condition which it diagnoses is expected to occur in only 1:100 cases tested. This again emphasises the need for the marker to be assessed in the appropriate setting — in this case a prospective clinical trial.