Objective: To determine the factors for relapse in patients with low-risk gestational trophoblastic tumor (GTT) treated with single-agent chemotherapy.
Methods: Between 1974 and 2000, 272 consecutive patients with low-risk GTT were initially treated with methotrexate (MTX), actinomycin D (Act-D) or etoposide chemotherapy. The primary remission rate, change of chemotherapy because of drug resistance or toxicity, and relapse rate were compared.
Results: Overall survival rate and primary remission rate for 272 patients were 100% and 75.7%, respectively. Primary remission rate was significantly higher in patients given etoposide than those given conventional MTX (P < 0.0001) or MTX-folinic acid (MTX-CF) (P = 0.0005). Twenty-four (8.8%) patients required a change of chemotherapy because of drug resistance. The frequency of drug resistance was significantly higher in patients treated with MTX-CF than those treated with etoposide (P = 0.006). Although maternal age, presence of metastasis, high pretreatment hCG titer, and planned hysterectomy did not influence the development of drug resistance, the new FIGO scores were significantly higher in patients who developed drug resistance. Relapse rate increased significantly in patients who had high FIGO scores and who required change of chemotherapy due to drug resistance.
Conclusions: All patients with low-risk GTT eventually attained complete remission, even though some developed drug resistance to the first-line chemotherapy. The relapse rate was significantly higher in patients with drug resistance than those with primary remission. Chemotherapy regimen that induces little drug resistance is desirable from the viewpoint of long-term prognosis.