684 Detecting Atypical Sentinel Lymph Nodes in Early-Stage Cervical Cancer

Introduction/Background Lymph node (LN) status is one of the most important prognostic factors among women with cervical cancer (CC). Sentinel lymph node (SLN) biopsy has the added benefit of detecting LN metastasis in uncommon locations that are not tipically included in a stantard lymphadenectomy. The aim of this study was to describe our institutional experience with SLNs using a hybrid tracer (ICG-99mTc nanocoloid) in patients with early CC in terms of detection rates and detection of uncommon SLN locations. Methodology A prospective, observational, descriptive, single-centre study conducted at Son Espases University Hospital between January 2019 and October 2023. Patients with clinical early-stage CC who underwent SLN mapping were included. External iliac and obturator nodes were defined as common SLN locations. Para-aortic, common iliac, presacral, internal iliac, and parametrial nodes were defined as uncommon locations. Results Thirty-nine cases of CC were included in the current study. Overall SLN detection rate was 97.4%, with 89.5% of cases occurring bilaterally. Positive SLNs were found in 21.1% of patients. Of the total SLNs (146), 10.3% corresponded to an atypical zone (the most frequent, common iliac vessels). To sum up, atypical lymphatic drainage was present in 8 out of 38 (21.1%) patients. The SLNs in the atypical area had a higher proportion of metastasis than the usual area (37.5% vs 16.7%; p=0.327); with 75% macro-metastases and 25% micro-metastases detected by ultrastaging. Parametrial nodes were detected in 15.7% of patients (four as SLNs and two in the histological study of the radical hysterectomy) – two of these (5.2%) with the presence of metastasis. Conclusion SLN biopsy can detect unusual drainage in a significant proportion of patients with CC. SLNs in atypical locations have a higher percentage of metastatic involvement, which consequently improves staging and tailoring therapy. Disclosures No disclosures conflict of interest.