Serum tumor marker half-life during chemotherapy in patients with germ cell tumors.

Approximately 80% of previously untreated men with metastatic germ cell tumors will be cured with cisplatin-based chemotherapy. Serum levels of alpha fetoprotein (AFP) or human chorionic gonadotropin (HCG) or both are increased in most of these patients. Pre-treatment clinical characteristics can be used to distinguish between "good" and "poor" risk patients who are either highly likely or unlikely to achieve a complete remission, respectively. A slow rate of decline of either AFP or HCG or both has been associated with an inferior survival in both good and poor risk patients. In multivariate analysis, the pre-treatment risk status and the post-treatment clearance of markers were independent and equal prognostic variables. Similarly, in patients receiving cisplatin+ifosfamide-based salvage chemotherapy, the rate of decline of HCG was an independent predictor variable in addition to the primary site and pre-treatment HCG levels for both overall and event-free survival. Prolonged half-life clearance of serum tumor markers is an important prognostic variable in both previously untreated as well as previously treated germ cel tumor patients. Treatment strategies can be based on marker clearance and prospective clinical trials are warranted.