The Clinical Value of Tumour Markers in the Management of Ovarian Cancer

It is now clear that the correct use of tumour markers in patients with epithelial ovarian carcinoma can make an impact on clinical management. Those of greatest current interest are CA 125, tissue polypeptide specific antigen, tumour-associated trypsin inhibitor and the mucins cancer-associated serum antigen and DVXl. Their value in screening is unproven and cannot be recommended outside clinical trials. They are all too non-specific for use in the diagnosis of ovarian carcinoma but when used with ultrasound can help in the differential diagnosis of a pelvic mass. Although elevated CA 125 concentrations prior to the third course of chemotherapy is the best indicator of poor prognosis, this information is not accurate enough to justify a change in therapy. The major role of CA 125 is in monitoring response to therapy. A precise definition of tumour response based on a 50% or 75% fall in serial CA 125 concentrations that is maintained for 1 month is as accurate as serial measurements of tumour size for determining whether a particular treatment is active. The role of regular CA 125 measurements during follow up is unclear. However, if there is suspicion of relapse and it is found that the CA 125 concentration has risen to over twice the upper limit of normal, the probability of relapse is so high as to make other investigations unnecessary. Patients with cancer of the ovary typically present with non-specific symptoms and advanced disease. Such cancer usually metastasizes as peritoneal deposits which are rarely palpable or detectable on scans. Tumour markers, therefore, have a greater potential value in the management of ovarian cancer than in virtually any other cancer type except choriocarcinoma.