Treatment outcomes according to various progestin treatment strategies in patients with atypical hyperplasia/endometrial intraepithelial neoplasia – Multicenter retrospective study (KGOG2033)

Objective: To investigate pathologic complete response (pCR) and recurrence outcomes using various progestin treatment strategies in patients with atypical hyperplasia/endometrial intraepithelial neoplasia (AH/EIN). Methods: Medical records of patients diagnosed with AH/EIN and undergoing follow-up endometrial biopsy after progestin treatment between 2011 and 2020 were retrospectively reviewed. Clinical factors and treatment outcomes were analyzed according to initial progestin treatment (oral progestin [OP], levonorgestrel-releasing intrauterine device [LNG-IUD], and combination), OP dose, and maintenance treatment using Pearson's χ², Fisher's exact test, and Kaplan-Meier analysis. Results: Of 124 patients included, 74, 37, and 13 were in the OP, LNG-IUD, and combination groups, respectively. The pCR rate was 79.8% and recurrence rate was 21.2%. The pCR rates within 3 and 6 months were significantly higher in the OP group than in the LNG-IUD group, but were not significantly different within 12 and 24 months. Recurrence rate was significantly higher in the OP group than in the LNG-IUD group. The pCR rate and recurrence rate had no significant differences between the combination group and the other groups. Excluding the LNG-IUD group, 53 and 34 patients received low- and high-dose OP, respectively. The pCR and recurrence rates were comparable between the low- and high-dose OP groups. Maintenance therapy was significantly associated with lower recurrence rate. Conclusions: Although OP alone achieved more short-term pCR than the other groups, more recurrences occurred after pCR than LNG-IUD alone. High-dose OP as well as combination of OP and LNG-IUD did not increase pCR or reduce recurrence. Maintenance therapy may reduce the recurrence rate after pCR.