Treatment of low-risk gestational trophoblastic neoplasia

Abstract

Low-risk gestational trophoblastic neoplasia (GTN), defined as FIGO/WHO score 0-6, is highly curable with an overall survival rate, which is approximately 100%. For most low-risk GTN patients, first-line single-agent chemotherapy with either methotrexate or actinomycin-D is recommended with overall complete human chorionic gonadotrophin (hCG) response rates of 60%-90% in mostly retrospective, non-randomised studies. The few randomised trials that exist are not appropriately powered or designed to define the optimal first-line treatment. Approximately 25%-30% of low-risk patients will develop resistance to initial single-agent chemotherapy with an increase in the FIGO score, a diagnosis of choriocarcinoma, higher pre-treatment hCG and the presence of metastatic disease being associated with an increase in the risk of resistance. The optimal treatment of patients scoring WHO 5 and 6 remains poorly defined given that approximately 70%-80% of these patients develop resistance to first-line single-agent chemotherapy, and there is an urgent need to refine the FIGO/WHO scoring system so that these patients can be identified for more intensive therapy from the outset. Despite this, almost all low-risk patients who experience treatment failure with first-line monotherapy will be cured with either sequential single-agent chemotherapy or multiagent chemotherapy with or without surgery. Given the associated increased short and longer-term toxicities associated with multi-agent chemotherapy, promising strategies to reduce the exposure of women to combination chemotherapy in low-risk disease have been investigated, including the use of carboplatin and immune check-point inhibitors. Further evaluation is required to define optimal patient selection, particularly with the use of immunotherapeutic agents given their significant increased costs and lack of longer-term safety data. Although there is a clear need to revise the FIGO/WHO (2000) scoring system, consistent international use of this is recommended to facilitate the comparison of data along with future focus in the development of international collaborative translational and clinical research, including randomised controlled trials.

Keywords: Actinomycin-D; Chemotherapy; FIGO/WHO (2000) scoring system; Low-risk gestational trophoblastic neoplasia; Methotrexate; Resistance.