Low-Risk Gestational Trophoblastic Neoplasia in Manitoba: Experience With Alternating Methotrexate and Dactinomycin

The aim of this study was to review the treatment and outcomes of low-risk gestational trophoblastic neoplasia (GTN) in Manitoba over more than 3 decades, with a focus on those treated with alternating methotrexate and dactinomycin, a protocol that has only rarely been described.

We retrospectively reviewed all patients with GTN referred to CancerCare Manitoba from January 1977 to December 2012. Cases were classified as low risk as per the modified WHO-FIGO prognostic scoring system (score, ≤6). Demographic, treatment, and outcomes data were abstracted, and descriptive statistics and time-to-event analysis were performed. The low-risk protocol used at CancerCare Manitoba consists of alternating single-agent use of methotrexate and dactinomycin, each for 5 days, on a 14-day cycle.

Sixty-seven cases of GTN were identified, of which 52 were low risk. Thirty-nine patients were initiated on alternating methotrexate and dactinomycin. Thirty-four (87.2%) achieved primary cure on this regimen, with a median of 4.4 cycles administered (range, 2-7). Median time to response was 56 days. One patient achieved cure after receiving a repeat course of methotrexate as their final cycle. Second-line multiagent chemotherapy was required by 4 patients. Two patients experienced grade 3 toxicities, and none greater than grade 3. There were no recurrences.

Alternating methotrexate and dactinomycin is an effective treatment protocol for low-risk GTN, with high rates of primary cure and acceptable toxicity.