Background: Serous endometrial intra-epithelial carcinoma (SEIC) is a rare condition affecting the lining of the uterus. It's a pre-cancerous change that might lead to cancer if not treated. Doctors aren't sure of the best way to manage it because it's so uncommon. A previous study looked at past cases in the Netherlands from 2012 to 2020. This study found that none of the 23 women with SEIC had their cancer spread during surgery, and none had a recurrence in the following three years. This suggests that a simpler surgery might be safe for patients with SEIC.

Methods: Information on disease details from patients who agree to participate in our study will be collected. All participants will fill out online forms and health questionnaires at several points: when they join the study, and again at six months, two years, and five years after their diagnosis. During the years after diagnosis, various details like health status, test results, treatments will be checked in the electronic medical record.

Results: This study is just starting, with the first patients expected to join on January 1, 2025.

Conclusion: A large international study is created to track SEIC patients over time. This will help us learn more about the condition and improve treatment strategies.

Inclusion Criteria:

• Serous endometrial intra-epithelial carcinoma (SEIC).
• Women older than 18 years of age.
• Women with understanding of Dutch or English language in reading and writing.

Exclusion Criteria:

• Diagnosis with a different type of endometrial neoplasm or invasive carcinoma.
• Previous and/or current treatment for another malignancy (<2 year before diagnosis of SEIC).

Only individuals with an uterus and endometrial disease are eligible.

Women with serous endometrial intra-epithelial carcinoma