study of low-risk gtn patients resistant to first-line chemotherapy with mtx in a tertiary hospital center

Background objective: this study aimed to determine the response rate and related factors for resistance to single-agent chemotherapy in low-risk gtn patients.materials methods: in a single-center retrospective descriptive study, all patients diagnosed with low-risk gestational trophoblastic neoplasia, referring to a tertiary hospital center in mashhad, iran, between 2013 and 2023, were included. clinical data were extracted from the hospital registry system. resistance to first-line single-agent chemotherapy was considered the primary result.results: out of 1015 cases of gtd, 135 cases of gestational trophoblastic neoplasia (13.3%) were recognized. 124(91.8%) patients were diagnosed with low-risk gtn. from low-risk gtn, 37(29.8%) patients received single-agent weekly methotrexate (50 mg/m2 im), while 87(70.16%) patients received 8 days of mtx-folinic acid as first-line treatment. 48.6% (n=18/37) did not respond to weekly mtx, and 18.4) patients did not respond to eight days of mtx-folinic acid. all these patients receive second-line chemotherapy. 72.6% (n = 90/124) achieved a complete response on first-line chemotherapy, and 34(27.4%) patients received actinomycin-d in the second line. the mean b-hcg titer before administration of actinomycin-d for 73.5% (n=25/34) patients was 294.4 iu/ml. in the second line, a complete response was achieved in 76.47% (n=26) while 23.53% (n=8) of patients got 3rd-line chemotherapy. the complete response rate for all low-risk gtns was 100%.conclusion: higher pretreatment serum hcg level, stage ii-iii, figo score 5-6, pathology choriocarcinoma, and previous-term pregnancy were the risk factors of resistance to first-line chemotherapy with methotrexate, highlighting the need for precise follow-up of patients with these criteria during the first line on single-agent chemotherapy.