Evaluation of a routine second curettage for hydatidiform mole: a cohort study

Objective The aim of this study was to evaluate routine second curettage for hydatidiform mole (HM) by comparing the characteristics and outcomes of developing gestational trophoblastic neoplasia (GTN). Study design This was a cohort study including 173 patients diagnosed with HM between January 2002 and August 2019 who were followed up at Nagoya University Hospital, Japan. After an evacuation, 105 and 68 patients were managed with the routine method (routine group) and elective method (elective group) for a second curettage, respectively. The routine second curettage was performed around 7 days after the first evacuation. Patients in the elective group underwent a second curettage if there was ultrasonographic evidence of molar remnants in the uterine cavity. Socio-clinical factors were retrospectively compared between the routine and elective groups, and between patients showing regression and those who developed GTN. Results The incidence of GTN was 15.2% in the routine group and 20.6% in the elective group, and the difference was not significant (P = 0.364). The median GTN risk score was significantly higher in the routine group than in the elective group (P = 0.033). Presence of a complete HM, gestational age, and a pre-treatment human chorionic gonadotropin level of >= 200,000 mIU/mL were independent risk factors for GTN in molar patients. Conclusion The incidence of GTN was unchanged but the risk score of GTN was higher in the routine group than in the elective group. Routine second curettage may not be necessary, but further study will be needed to confirm this.