Background: We present normograms for human chorionic gonadotropin (hCG) regression in patients with high-risk gestational trophoblastic neoplasia (GTN) successfully treated with multiagent chemotherapy in order to predict treatment resistance.
Patients and methods: We collected data for 46 patients with high-risk GTN treated with EMA/CO (etoposide, methotrexate, actinomycin D, cyclophosphamide and vincristine) who had hCG values available. Patients were classified as having methotrexate (MTX)-resistant disease (n = 22) or primary high-risk disease (n = 24). The 10th, 50th and 90th percentiles of the hCG before every chemotherapy course were calculated and plotted in normograms.
Results: Half of the patients treated for MTX-resistant disease and primary high-risk disease had normal hCG levels before the third and sixth course of chemotherapy, respectively. In patients with MTX-resistant disease, the 90th percentile line fell below normal before the start of the fourth course, whereas in patients with primary high-risk disease this was not the case until the eighth course of chemotherapy.
Conclusion: Resistance to EMA/CO treatment for high-risk GTN, as illustrated by examples, could be predicted using normograms for hCG resistance. Normograms differed depending on the indication for multiagent chemotherapy due to much higher initial hCG values in patients with primary high-risk disease compared with those treated for MTX-resistant disease.