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.