Study of low-risk GTN patients resistant to first-line chemotherapy with MTX in a tertiary hospital center

Introduction: This study aimed to determine the response rate and related factors for resistance to single-agent chemotherapy in low-risk GTN patients.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 ۲۰۱۳ and ۲۰۲۳, 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 ۱۰۱۵ cases of GTD, ۱۳۵ cases of gestational trophoblastic neoplasia (۱۳.۳%) were recognized. ۱۲۴ (۹۱.۸%) patients were diagnosed with low-risk GTN. From low-risk GTN, ۳۷ (۲۹.۸%) patients received single-agent weekly Methotrexate (۵۰mg/m۲ IM), while ۸۷ (۷۰.۱۶%) patients received ۸ days MTX –folinic acid as first-line treatment. ۴۸.۶%(N=۱۸/۳۷) did not response to weekly MTX, ۱۸.۴%(N=۱۶/۸۷) patients did not response to ۸days MTX-Folinic acid. All these patients receive second-line chemotherapy. ۷۲.۶% (n = ۹۰/۱۲۴) achieved complete response on first-line chemotherapy and ۳۴(۲۷.۴%) patients received Actinomycin in the second line. The mean B-HCG titer before administration of Actinomycin-D for ۷۳.۵%( n=۲۵/۳۴) patients was ۲۹۴.۴ IU/ml. In the second line, complete response was achieved in ۷۶.۴۷% (n = ۲۶) while ۲۳.۵۳% (n ۸) patients got ۳rd-line chemotherapy. The complete response rate for all low-risk GTNs was ۱۰۰%.Conclusion: Higher pretreatment serum hCG level, stage II-III, FIGO score۵-۶, 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.

Keywords:

Gestational trophoblastic neoplasia , chemo-resistance , Methotrexate , Actinomycin , Molar pregnancy