Prognostic significance of a decline in serum human chorionic gonadotropin levels after initial chemotherapy for advanced germ-cell carcinoma.

We studied 40 consecutive patients with advanced germ-cell carcinoma and elevated serum levels of human chorionic gonadotropin (HCG) to assess the prognostic value of the magnitude of the decline in HCG levels after chemotherapy. If serum levels failed to become normal after the first chemotherapy cycle and if the day-22 HCG level/day-1 level was greater than 1/200 (0.005), an incomplete response to chemotherapy could be predicted with a sensitivity of 90% and a predictive value of 94%. Conversely, if the day-22 level was within normal limits, or if the day-22 level/day-1 level was less than 1/200, a successful response to chemotherapy (defined as a 1-year disease-free interval following cessation of chemotherapy) could be predicted with a sensitivity of 95% and a predictive value of 91% after one chemotherapy cycle. Overall, the long-term response to chemotherapy was correctly predicted in 37 of 40 patients (p less than 0.0001, compared with actual patient outcome using the chi-squared test).