984 Mapping sentinel lymph node with hibrid tracer (99Tc-ICG) in apparent early-stage ovarian cancer (HibrOv). Pilot experience

Introduction/Background Published experience for sentinel Lymph node (SLN) in early-stage ovarian cancer is limited. The SENTOV clinical trial technique appears to be feasible but requires a longer learning curve than SLN techniques for other types of gynecologic tumors. The aim od this study is to assess the feasibility of SLN biopsy in patients with clinical stage I-II ovarian cancer during our learning curve. The secondary objective is to evaluate the SLN detection rate, location and involvement of the SLN. Methodology Controlled, non-randomized, prospective single-center, pilot clinical trial. We recruited 22 consecutive patients (Jan/21-Dec23) with suspicious ovarian mass in apparent early stage by radiological imaging or re-staging surgery. After anesthetic induction and exploration of the abdominal cavity, 0.2 ml 37 MBq of hybrid tracer (ICG-99mTc) was injected into the infundibulopelvic and utero-ovarian ligament via laparoscopic/robotic or open surgery. The ovarian mass was removed and referred for intraoperative analysis. If malignancy was confirmed, the SLN was removed, bilateral pelvic and para-aortic lymphadenectomy was performed and the staging surgery was completed. If the intraoperative report was benign, images were taken with a portable Gammaprobe to check whether drainage occured. Results 22 patients were included. Injection was feasible in 21 patients (95,5%). In one patient the tracer was overflowed and the identification of SLN was no possible. The overall detection rate was 95.5% (21/22). SLN were detected in pelvic and para-aortic area en 14/21 patients (66,7%), in 4 patients SLN migrated only in pelvic area (19%) and Three (14,3%) mapped only in para-aortic region. Lymph node involvement was 15,4% (2/13). Micrometastasis was found in two SLN by ultrastaging technique. There were no intra or postoperative events related with the tracer or the technique. Conclusion SLN in early-stage ovarian seems to be feasible with an optimal overall detection rate during the learning curve. More prospective and multicentric trials, are necessary. Disclosures Authors have not disclousures of interest.