797P Impact of consolidation cycles in predicting recurrence in patients treated with EMA-CO for high-risk gestational trophoblastic neoplasia

EMA-CO is the most used combined chemotherapy regimen for treating high-risk gestational trophoblastic neoplasia (GTN) patients. It is administered weekly until normalization of hCG levels, followed by two consolidation cycles. Premature discontinuation of EMA-CO chemotherapy due to dose-limiting toxicities may occur before achieving the target hCG threshold. Despite its widespread use, the effectiveness of consolidation cycles in preventing recurrence in GTN patients remains unclear. In this study, we aimed to evaluate the impact of EMA-CO consolidation cycles on recurrence. We conducted a non-interventional, retrospective study in patients selected from the French Center for Trophoblastic Diseases in Lyon and identified 276 patients with a GTN diagnosis and treated with EMA-CO regimen between November 1999 and November 2020 from our database. Exclusion criteria for this study included resistance to EMA-CO chemotherapy (n=31). We assessed the impact of two cycles of EMA-CO consolidation on the 2-year recurrence-free survival (RFS). A total of 245 patients met the eligibility criteria for this study, of whom 88.6% (217/245) received consolidation cycles of EMA-CO. Choriocarcinomas were diagnosed in 42% (102/245) of the patients, while invasive mole was observed in 58% (143/245) of cases. The median FIGO score was 8 (range 1 – 19). After a median follow-up of 23 months, the 2-year RFS was 93% (95%CI 0.90 to 0.96) in the consolidation group and 90% (95% CI 0.79 to 1.0) in the group of patients who didn’t receive consolidation cycles (HR 0.79; 95% CI 0.23 to 2.72, p=0.71). Grade ≥ 2 adverse events occurred in 43% of patients, with neutropenia being the most frequent (31%). In this study, the 2-year RFS was not significantly different between the groups. These findings suggest that consolidation cycles may not influence recurrence in patients with gestational trophoblastic neoplasia. Considering the non-negligible toxicity of EMA-CO, our results raise the question of optimizing therapy through de-escalation and/or shortening of chemotherapy after hCG normalization.