693 Is18F-FDG-PET/CT an effective tool for staging cervical cancer before surgery?

Introduction/Background For cervical cancer (CC) nodal status is one of the most important prognostic factors, so the recently revised FIGO staging system now includes images and pathology assessment. 18F-FDG-PET/CT is currently the most effective and precise test for nodal assessment but it could have some limitations mainly in small metastatic lymph nodes (LN). Methodology A retrospective, observational, descriptive, single-centre study was conducted at Son Espases University Hospital from September 2018 to December 2023. Patients with early-stage and locally advancer CC (LACC) who had had 18F-FDG-PET/CT requested during their pre-treatment study were included and underwent surgical staging. Results Early-stage CC represented 14.7% (5/34) whereas advanced-stage 85.3% (29/34). Out of the women with LACC, 75.8% (22/29) presented 18F-FDG-PET/CT which suggested the presence of pelvic node metastasis. Of the 24% (7/29) of patients with no suspicion of pelvic nodal involvement, all had parametrial involvement. None had suspected para-aortic LN involvement. Out of 34 patients who presented 18F-FDG-PET/CT negative for para-aortic nodal disease, 33 were true negatives. Five false-negatives were found: four patients with clinical FIGO stage IB2 turned out to have pelvic SLN metastases and were upstaged to FIGO IIIC1, while one patient with clinical stage IIIC1 had a micrometastasis in the para-aortic area. Two false positives were found: one pelvic case and one para-aortic case. 18F-FDG-PET/CT was performed again after surgery to confirm that the uptake LN had been resected. After surgical staging, 14.7% of patients were upstaged. Conclusion In our series, 18F-FDG-PET/CT could not detect pelvic nodal metastases in the pre-treatment study of women with early-stage CC and could be avoided. This supports the need to continue with sentinel lymph node detection. In contrast, in cases of LACC, 18F-FDG-PET/CT showed a high prediction of para-aortic nodal status. In these cases, it should be considered whether surgical staging by para-aortic lymphadenectomy is necessary Disclosures The authors have no conflicts of interest.