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Abstract
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 >10 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).
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 encrypted
Risk of lymph node metastases, stratified by the most important risk factors
Conclusions 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.