One-step nucleic acid amplification versus ultra-staging to detect sentinel lymph node metastasis in endometrial cancer: a randomized, multi-center, controlled trial (SENT-OSNA Trial)

BACKGROUND: Sentinel lymph node (SLN) biopsy is the standard of care in apparent early-stage endometrial cancer. However, ultra-staging protocols have not been standardized, which may contribute to variability in the detection of SLN metastases. The one-step nucleic acid amplification (OSNA) method has been proposed as a rapid and standardized technique to diagnose SLN metastasis. PRIMARY OBJECTIVE: To compare the ability to detect SLN metastasis between OSNA and ultra-staging. STUDY HYPOTHESIS: OSNA is non-inferior to ultra-staging in detecting lymph node metastases. TRIAL DESIGN: This is a prospective, multi-center, randomized, non-inferiority trial. MAJOR INCLUSION/EXCLUSION CRITERIA: The trial includes patients with histologically confirmed endometrial cancer and apparent (pre-operative) uterine-confined tumor, who are undergoing an attempt at SLN mapping. Exclusion criteria are uterine sarcoma (except for carcinosarcomas), de-differentiated or un-differentiated histology, fertility-sparing management, neoadjuvant therapy, previous surgery to pelvic lymph nodes, and suspicious lymph nodes on pre-operative imaging. PRIMARY ENDPOINT: Incidence of SLN metastasis in the OSNA group versus the ultra-staging group. SAMPLE SIZE: Assuming a maximum allowable difference of -4% in the proportion of patients with detected lymph node metastases (node-positive proportion) to declare non-inferiority, a power of 80%, and a significance level of 2.5% (one side), a sample size of 1922 (961 per arm) is needed. ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Four years of accrual, with estimated results to be presented in 2029. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (NCT06935305).