Rationale: Preoperative identification of patients at risk for lymph node metastasis (LNM) is challenging in endometrial cancer (EC). Therefore, a Bayesian network model called ENDORISK was developed and validated in three external cohorts to improve preoperative risk stratification. The next step is to implement and evaluate whether use of the model improves daily clinical practice. Objective: The ENDORISK implementation (ENDORISK-I) study aims to prospectively evaluate whether implementation of ENDORISK in daily clinical practice improves preoperative risk stratification. Study design: A stepped wedge non inferiority study in which two oncology regions will consecutively start implementation of ENDORISK with one year interval. The ENDORISK model will be filled in and used in preoperative treatment counselling. Results will be compared to current standard clinical care which is prospectively evaluated in both regions since March 2022 in the 'evaluation of care in endometrial cancer' study (2021-7400). Study population: all consecutive patients recently diagnosed with early stage EC who are eligible for surgical treatment, who understand Dutch and are able to fill in a digital or paper questionnaire can be included. Main study parameters/endpoints: The ENDORISK implementation (ENDORISK-I) study aims to prospectively evaluate implementation of ENDORISK in daily clinical practice by investigating:

• The proportion of identified LNM in patients with lymph node staging (positive predictive value (PPV)) compared to standard care
• Proportion of patients who decide to have lymph node status assessed in ENDORISK care compared to standard care
• Preoperative information provision for patients and shared-decision making with the use of ENDORISK compared to standard care
• Patients' disease- specific-, overall survival, and health-related quality of life compared to standard care
• Patients' and doctors' use of and experiences with the ENDORISK-model
• Impact of ENDORISK on regional care costs

Inclusion Criteria:

• Diagnosed with early stage (FIGO stage I-II) endometrial carcinoma (every grade permitted)
• Eligible for primary surgical treatment (neo-adjuvant therapy is permitted)

Exclusion Criteria:

• Unable to give informed consent
• No understanding of Dutch or English language
• Rare types of endometrial cancer, such as endometrial stroma cell sarcoma

Only anonymized datasets (without patient numbers, date of birth or name) will be shared with other people relevant to the study or relevant to additional studies as reported in the patient information folder.

Patients are requested whether or not they give permission to use anonymized data from this study for further research into cervical cancer.

IPD will be available after the end of the study.

Researchers within the RadboudUMC will be able to get access upon request and review of research aim/protocol