Introduction/Background Methotrexate (MTX) is the gold standard treatment of gestational trophoblastic neoplasia (GTN), and it is usually administered until negative beta-human chorionic gonadotropin (hCG) levels, after which a variable number of consolidation courses is recommended. Aim of this study was to evaluate the relationship between the number of consolidation courses and relapse rate.

Methodology Patients with low-risk GTN treated with first-line MTX in 12 Italian centers between 1981 and 2021 were retrospectively identified and selected for the analysis. Exclusion criteria were exclusive surgical treatment, missing data on number of courses or non-standardized definitions of chemoresistance.

Results Among 435 patients treated for low-risk GTN, 333 patients were eligible for the analysis. In total, 98 patients (29.4%) switched to second-line treatment for chemoresistance. Seven patients (2.1%) relapsed after completion of first-line: 2 patients had a FIGO score of 5–6, 1 of 4, and the remaining lower than 4. Histological diagnosis in relapsed women was choriocarcinoma in 2 cases, hydatidiform mole in the remaining 5. Forty-one patients (17.4%) underwent 2 consolidation courses and had no relapse; 132 (56.1%) received 3 consolidation courses with a relapse rate of 2.2%; 39 patients (16.5%) received more than 3 consolidation courses with a relapse rate of 10.2%. Patients undergoing 2 consolidation courses had a FIGO score below 4 in 95% of cases.

Conclusion The number of consolidation courses after remission of low-risk GTN does not appear to have an impact on relapse rate. Probably, patients with lower scores can safely receive 2 courses of consolidation MTX. The higher relapse rate in patients who received more than 3 courses of MTX is explained by the higher score, and hence the higher risk of relapse, of these women.

Disclosures None.