Effects of multiagent chemotherapy and independent risk factors in the treatment of high-risk GTT - 25 years' experiences of KRI-TRD

A retrospective and comparative study of high-risk gestational trophoblastic tumor (GTT) treated with different chemoregimen from 1971 to 1995 was performed and to find most effective chemotherapy regimen and independent risk factors. Three hundred seven patients in scoring over 8 points in WHO classification were categorized into high-risk group among 802 GTT cases received chemotherapy in the 2,418 GTD patients registered at KRI-TRD (Korean Research Institute for Gestational Trophoblastic Disease), Catholic University Medical College in Korea. Study groups of multiagent combination chemotherapy in 227 patients of the high-risk GTT were divided such as 49 cases of combination chemotherapy with MTX + folinic acid acid Act-D, 40 cases of MAC regimen, 42 cases of CHAMOCA regimen, and 96 cases of EMA/CO. Initial tumor response according to hCG titer decrease was found in good response (log fall) 69.8%, of EMA/CO regimen group. On the other hand, good response was shown in only 24.5% of MTX + ACT-D, 32.5% of MAC regimen, and 52.4%, of CHAMOCA regimen respectively. Remission rate of EMA/CO regimen was 90.6% (87/96) and courses of chemotherapy until remission was 85 +/- 2.2. However, remission rate of other regimens of MTX + Act-D, MAC, and CHAMOCA were 63.3%, (31/49) 67.5% (27/40) and 76.2% (32/45) respectively, with 10.0 +/- 4.0, 10.7 +/- 4.3, 9.1 +/- 3.9 chemotherapy courses respectively until remission. Therefore, EMA/CO regimen groups were found to have low drug toxicity, early remission and a low failure rate. In the study of independent risk factors in the 165 cases of high-risk gestational trophoblastic tumor patients received EMA/CO regimen, stepwise Coxs proportional hazard's regression of prognostic factors using multivariate analysis revealed tumor age, number of metastatic organs, metastatic site and inadequate previous chemotherapy. According to the performance of fitted logistic regression model, the prediction rate of death and survival was 80.5%. Conclusions: The most effective chemotherapy to high-risk GTT was EMA/CO regimen than other regimens. The following factors showed poor prognosis; 1) Tumor age is over 12 month, 2) more than 2 organs had metastatic lesion, 3) inadequate previous therapy that includes unplanned operation and inadequate previous chemotherapy.