Risk factors for second‐line dactinomycin failure after methotrexate treatment for low‐risk gestational trophoblastic neoplasia: a retrospective study

OBJECTIVE: To find risk factors for second‐line dactinomycin failure in patients with low‐risk gestational trophoblastic neoplasia (GTN). DESIGN: Retrospective multicentre study. SETTING: Tertiary reference centre. POPULATION: Patients with low‐risk GTN, treated with dactinomycin after methotrexate (MTX) failure. METHODS: Retrospective analysis of 45 patients with low‐risk GTN treated with dactinomycin after MTX failure, registered between 2006 and 2018. MAIN OUTCOME MEASURES: Treatment outcome and risk factors for second‐line dactinomycin failure. RESULTS: Thirty patients (66.7%) were cured and 15 patients (33.3%) required third‐line therapy. Type of antecedent pregnancy and hCG levels pre‐dactinomycin were risk factors for failure in univariate analysis (odds ratio [OR] 19.30, 95% CI 2.04–182.60, P = 0.01 and OR 2.77, 95% CI 1.18–6.50, P = 0.02, respectively). Level of hCG pre‐dactinomycin remained a significant risk factor in multivariate analysis (OR 2.93, 95% CI 1.02–8.40, P = 0.045). Complete remission (CR) was achieved in 83.3% of patients with pre‐dactinomycin hCG levels <10 ng/ml, in 75% with hCG levels between 10 and 20 ng/ml, in 66.7% with hCG levels between 20 and 30 ng/ml, and in 50% with hCG levels between 30 and 40 ng/ml. No patients with hCG levels >40 ng/ml achieved CR. Patients with dactinomycin failure were treated surgically and/or with multi‐chemotherapy; all except one achieved CR. CONCLUSIONS: Treatment with dactinomycin after MTX failure in patients with low‐risk GTN resulted in CR in 66.7%. Chance of curative treatment with dactinomycin is strongly related to the hCG level. TWEETABLE ABSTRACT: Chance of curative treatment with dactinomycin after MTX failure in GTN patients is strongly related to the level of hCG pre‐dactinomycin.