Background: The benefit of lymphadenectomy on survival in stage 1 endometrial cancer remains uncertain. STATEC is a surgical trial designed to evaluate the use of nodal status after lymph node dissection to tailor adjuvant treatment in patients with high risk apparent stage I endometrial cancer. Methods: DESIGN: Randomised (1:1), controlled, two-arm, phase III, multicentre, international, non-inferiority trial. ELIGIBILITY: High risk apparent FIGO stage I endometrial cancer on diagnostic endometrial sampling OR hysterectomy. If randomisation occurs after hysterectomy and BSO: FIGO grade 3 endometrioid or mucinous carcinoma, high grade serous, clear cell, undifferentiated or dedifferentiated carcinoma or mixed cell adenocarcinoma or carcinosarcoma. STRATIFICATION: participating site, histology, lymphovascular space invasion, timing of hysterectomy and bilateral salpingo-oophorectomy (BSO). TREATMENT: Arm 1: Hysterectomy and BSO, plus intraoperative bilateral pelvic and para-aortic lymph node dissection + adjuvant therapy if node positive or stage III. Arm 2: Hysterectomy and BSO+ adjuvant therapy based on stage and uterine factors. ENDPOINTS: Overall survival (primary), disease-free, endometrial cancer-event free and endometrial cancer-specific survival, pelvic and extra-pelvic relapse-free survival, cost-effectiveness, surgical adverse events, quality of life and performance of sentinel lymph node assessment (secondary). QUALITY ASSURANCE: surgical specimen processing and microscopy to local specialist gynaecological oncology site pathologists, central pathology (10% of UK patients) and surgical imaging of all Arm 1 patients. Recruitment: 4 years, with 5 years follow up. STATISTICS: Using the exponential parameter of 0.0040, allowable hazard ratio of 1.272, a sample size of 2000 (500 deaths) will provide 85% power, and 5% two-sided statistical significance. With 80% power, the minimum sample size is 1720 patients (430 deaths). CURRENT ENROLMENT (as of February 2018): STATEC is open in the UK, Australia and New Zealand. 7 patients have been enrolled. STATEC is registered with. Clinical trial information: NCT02566811