290O - Effect of sentinel node mapping strategy in robotic surgical treatment of endometrial cancers

Abstract

Background: Surgical staging is recommended to prognosticate and plan adjuvant therapy. Sentinel lymph node (SLN) mapping has been studied as an alternative to full lymphadenectomy in surgical staging protocol. We report our experience with SLN mapping using blue dye under robotic platform. Methods: All patients with clinically stage 1 endometrial carcinoma undergoing robotic assisted staging surgery were retrospectively reviewed. Total hysterectomy/BSO and pelvic lymphadenectomy is frequently used. One surgeon routinely apply SLN mapping in all cases using methylene blue dye. Standard patients’ demographics, pathology, and treatment related variables were abstracted. Descriptive, Chi Square and logistic regression were used to summarize, and detect significant associations between clinical variables and the detection of nodal metastasis. Cox regression was used to model time to disease recurrence. Results: From Nov 2011 to May 2016, 469 patients underwent robotic assisted staging. Full lymphadenectomy was done in 409 patients with 60 patients had SLN mapping. 372 patients (79%) had grade 1 on preop biopsy with 290 (78%) confirmed grade 1 based on final hysterectomy. There was significant association between tumour size (>2cm) and upgraded final tumour grade (OR 1.24 p = 0.005). There was no association between SLN mapping use and tumour grade, depth of invasion, LVSI, cervical stromal invasion. Nodal metastasis was observed in 5/409 (1.2%) lymphadenectomy patients versus 5/60 (8.3%) patients with SLN mapping (p < 0.001). Logistic regression model including grade (1 vs 2/3), histology (endometroids vs non endometroids), cervix stromal involvement (yes vs no), myometrial invasion (none vs less than 50% vs more than 50%), and SLN mapping revealed 2 independent predictive variables for nodal metastasis: Non-endometroids histology: OR 5.02 (95% CI 1.26-19.96 p = 0.02) and SLN mapping: OR 7.80 (95% CI 2.06-29.58 p = 0.002). In patients with endometroids histology and negative nodes, SLN mapping was not associated with increased risk for recurrence. Conclusions: SLN mapping can improve the sensitivity of detection of modal metastasis with no increased risk for recurrence in low risk disease. Legal entity responsible for the study: Dr Tien Le Funding: None Disclosure: All authors have declared no conflicts of interest.