GnRH-a-based fertility-sparing treatment of atypical endometrial hyperplasia (AEH) and early endometrial carcinoma (EC) patients: a multicenter, open-label, randomized designed clinical trial protocol.

Background: Around 4% of women receive an endometrial cancer diagnosis before turning 40, mainly those without prior childbirth experience and a strong desire to preserve their ability to conceive. Consequently, for young patients diagnosed with atypical endometrial hyperplasia (AEH) or early endometrial carcinoma (EC), a fertility-preserving approach employing high-dose oral progesterone has been adopted. However, previous research has shown a notable relapse rate. Furthermore, the extended use of substantial oral progesterone doses may hinder ovarian function and raise the risk of weight gain, liver issues, blood clotting, and breast cancer. We previously assessed the clinical effectiveness and pregnancy outcomes of gonadotropin-releasing hormone agonist (GnRH-a) based re-treatment for women with EC and AEH who did not respond to oral progestin therapy but achieved favorable treatment results and reproductive outcomes.

Methods: This study will be an open-label, two-armed, randomized, investigator-initiated multicenter trial evaluating the combination of GnRH-a with the levonorgestrel-releasing intrauterine system or the combination of GnRH-a with an aromatase inhibitor (comprising a subcutaneous GnRH-a injection every 4 weeks and daily oral letrozole 2.5 mg). A total of 226 participants will be randomly allocated to one of the two treatment groups in a 1:1 ratio. The primary objective is to determine the effectiveness of GnRH-a-based re-treatment in achieving a complete response (CR) at 24 weeks for patients with AEH or EC. Secondary objectives include assessing the pregnancy rate 12 weeks after treatment, as well as post-treatment pregnancy outcomes and the rate of recurrence.

Ethics and dissemination: The protocol received approval from the Institutional Review Board of Peking Union Medical College Hospital and from boards at five other institutions. The trial will adhere to the principles outlined in the World Medical Association's Declaration of Helsinki and follow Good Clinical Practice standards. The trial results will be disseminated through publication in a peer-reviewed journal.

Conclusions: Prospective evidence supporting conservative treatment for EC and AEH is limited. There is a need for new approaches that can achieve higher CR rates with fewer side effects. This trial will assess the effectiveness of GnRH-a-based fertility-sparing treatment in obese women and recurrent patients, offering a promising alternative for patients with EC and AEH.

Trial registration number: Chinese Clinical Trial Registry ChiCTR2200067099. Registered on December 27, 2022.