Comparison of diagnostic accuracy between endometrial curettage and aspiration biopsy in patients treated with progestin for endometrial hyperplasia: a Korean Gynecologic Oncology Group study

OBJECTIVE: To compare the diagnostic accuracy of dilatation and curettage (D&C) versus endometrial aspiration biopsy in follow-up evaluation of patients treated with progestin for endometrial hyperplasia (EH). METHODS: A prospective multicenter study was conducted from 2015 to 2018. Patients with EH were treated with progestin, one of the following three treatment regimens: oral medroxyprogesterone acetate (MPA) 10 mg/day for 14 days per cycle, continuous MPA 10 mg/day or the levonorgestrel-releasing intrauterine system (LNG-IUS). At 3 or 6 months of treatment, endometrial tissues were obtained via 2 methods in each patient: aspiration biopsy, followed by D&C. The primary outcome was the consistency of the histologic results between the 2 methods. The secondary outcome was the regression rate at 6 months of treatment. RESULTS: The study population comprised 65 patients (55 with non-atypical hyperplasia, 10 with atypical hyperplasia). During the follow-up, a comparison of the pathologic results from aspiration biopsy and D&C was carried out for the 65 cases. Thirty-eight cases were diagnosed as EH by D&C. Among these, only 24 were diagnosed with EH from aspiration biopsy, for a diagnostic concordance of 63.2% (ĸ=0.59). Forty-four patients were followed up at 6 months, and the regression rate was 31.8% (14/44). Responses were obtained for 41.7% (5/12) of the cyclic MPA group, 58.3% (7/12) of the continuous MPA group and 10% (2/20) of the LNG-IUS group. CONCLUSION: As a follow-up evaluation of patients treated with progestin for EH, aspiration biopsy is less accurate than D&C and might not be a reliable method. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02412072.