An assessment of combined tumour markers in patients with seminoma: Placental alkaline phosphatase (PLAP), lactate dehydrogenase (LD) and β human chorionic gonadotrophin (βHCG)

Abstract

We have assessed the tumour markers placental alkaline phosphatase (PLAP), lactate dehydrogenase (LD), and human chorionic gonadotrophin (β HCG) using 2, 000 serum samples from 286 patients with seminoma. The ROC curves show that no one marker performs adequately for the detection of disease either at initial staging or during follow-up. We used a Markov model heuristically to devise strategies, in which marker results were assessed in combination, which might be useful in clinical practice. We found that the best strategy was to consider a test result abnormal only if either the β HCG was >6 Ul-1 or the LD was >400 U l-1 arid the PLAP level was >60 Ul-1. This will detect about 50% of patients with disease and the false-positive rate is 2%. In practical terms this means that PLAP need only be estimated in patients whose βHCG is <6 Ul-1 and whose LD is >400 Ul-1. © 1991 Macmillan Press Ltd.