Manuela Alessio

Outcomes of low-risk endometrial cancer with isolated tumor cells in the sentinel lymph nodes: a prospective, multi-center, single-arm, observational study (ENDO-ITC study)

It is unclear whether isolated tumor cells (ITCs) in sentinel lymph nodes (SLNs) adversely affect prognosis, especially in low-risk endometrial cancer. In a retrospective study, we showed a worse recurrence-free survival for low-risk endometrial cancer with ITCs than the node-negative group. Our aim is to evaluate whether the likelihood of disease recurrence differs between a prospective cohort of patients with low-risk endometrial cancer with ITCs and an historical cohort with negative SLNs. We hypothesize that patients with low-risk endometrial cancer and ITCs will have a worse recurrence-free survival than patients who are node-negative. This is a prospective, multi-center, single-arm observational study. Consecutive patients with low-risk endometrial cancer with ITCs in the SLNs will be accrued. Observation only will be suggested after surgery. We will include patients with endometrial cancer undergoing pelvic SLN biopsy and ultra-staging with the following characteristics: endometrioid histology, grades 1 to 2, <50% myometrial invasion, without substantial/extensive lympho-vascular space invasion. ITCs in SLNs are defined as tumor cell aggregates ≤0.2 mm or <200 cells. The primary end point is recurrence-free survival, measured from the date of surgery to the date of recurrence, death, or last disease evaluation. With a sample size of 132 women with low-risk endometrial cancer and ITCs, a 1-sided log-rank test achieves 85% power at a 0.05 significance level to detect an HR of 2.1. The expected number of events during the study is 17.3. The study duration will be 60 months: 24 for enrollment and 36 for follow-up. The results are expected in 2029. ClinicalTrials.gov: NCT06689956.