Prediction of necrosis after chemotherapy of advanced germ cell tumors: results of a prospective multicenter trial of the German Testicular Cancer Study Group

PURPOSE: We evaluated the prognostic parameters of necrotic residual tumors after chemotherapy of advanced germ cell tumors to improve on the current indications for surgery. MATERIALS AND METHODS: Between January 1996 and January 2000, in 8 centers of the German Testicular Cancer Study Group, preoperative parameters were assessed to predict necrosis in the residual tumors of 261 patients with retroperitoneal residual tumor resection after first (92%) and second line (8%) chemotherapy. RESULTS: Of 232 evaluable patients 39 had pure seminoma and 5 had viable cancer (1 with seminoma) in the residual tumor. Of the remaining 193 patients with nonseminoma 35% had necrosis, 34% teratoma and 31% had viable carcinoma in the residual tumor. After multivariate analysis and exclusion of patients with seminoma, the 3 parameters independently predictive of necrosis were alpha-fetoprotein before chemotherapy less than 20 ng/ml, and tumor volume before and after chemotherapy. A mathematical model to predict necrosis yielded a test accuracy of 75%, a sensitivity to predict necrosis of 52% and a specificity of 87%. CONCLUSIONS: Patients with pure seminoma should not undergo residual tumor resection because 97% of patients who received adequate chemotherapy were found to have no residual seminoma. In cases of nonseminoma alpha-fetoprotein values before chemotherapy less than 20 ng/ml and a high percentage of shrinkage during chemotherapy reliably predicted only 19% of cases of necrosis. Therefore, this model is clinically irrelevant and patients with minimal residual disease should undergo surgery. New methods are necessary to improve the preoperative selection of patients after chemotherapy.