RT Journal Article SR Electronic T1 2022-LBA-1282-ESGO Identifying women with early-stage cervical cancer at low risk of lymph node metastases, in a large international cohort – A logistic regression analysis, without sharing privacy-sensitive patient data JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A467 OP A468 DO 10.1136/ijgc-2022-ESGO.1010 VO 32 IS Suppl 2 A1 Wenzel, Hans A1 Hardie, Anna Norberg A1 Bekkers, Ruud A1 Falconer, Henrik A1 Høgdall, Claus A1 Jensen, Pernille A1 Lemmens, Valery A1 Martin, Frank A1 Moncada-Torres, Arturo A1 Nijman, Hans A1 van der Aa, Maaike A1 Schnack, Tine A1 , A1 , YR 2022 UL http://ijgc.bmj.com/content/32/Suppl_2/A467.2.abstract AB Introduction Standard treatment of early-stage cervical cancer is radical hysterectomy with pelvic lymphadenectomy. However, a generic benefit of systematic lymphadenectomy is questionable, as most women will not have metastatic nodes. This study aimed to classify the most important risk factors of lymph node metastases (pN+) and to identify a group of women at low risk of pN+, in a large cohort of Danish, Swedish and Dutch women, using federated learning.Methods Women diagnosed with cervical cancer between 2005–2020 were identified from nationwide population-based registries: the Danish Gynaecological Cancer Database, Swedish Quality Registry of Gynaecologic Cancer and Netherlands Cancer Registry. Inclusion criteria were: squamous cell carcinoma, adenocarcinoma or adenosquamous carcinoma; FIGO 2009 stage IA2, IB1 and IIA1; treatment with radical hysterectomy and pelvic lymph node assessment. We applied privacy-preserving federated logistic regression to identify risk factors of pN+ (figure 1). Significant factors were used to identify a low-risk group (pN+ &le5%).Results A total of 3,606 women were included. The most important risk factors of pN+ were lymphovascular space invasion (LVSI) (odds ratio [OR] 5.16, 95% confidence interval [CI] 4.59–5.79), tumour size 21–40 mm (OR 2.14, 95% CI 1.89–2.43) and depth of invasion &gt10 mm (OR 1.81, 95% CI 1.59–2.08]). Tumours without LVSI, a size ≤20 mm and a depth of invasion ≤10 mm were associated with a low risk of pN+ (2%, 95% CI 2–3%) (table 1).Abstract 2022-LBA-1282-ESGO Figure 1 Approaches to analysing data from different sources; a) Centralisation. This is the traditional approach, but has several disadvantages such as loss of data control logistics data governance and (most importantly) putting at risk sensitive patient data. b) Federated warring in this docentralised approach, privacy-sensitive patient data are not shared, but kept undisclosed and safe at their original location. Communication within the infrastructure is end-to-end encryptedView this table:Abstract 2022-LBA-1282-ESGO Table 1 Risk of lymph node metastases, stratified by the most important risk factorsConclusions LVSI, tumours size and depth of invasion were the most important risk factors of pN+. Based on that, we identified a group at very low risk of pN+, in whom sentinel lymph node mapping should be considered to replace radical pelvic lymphadenectomy.