Search

Background: Bayesian networks (BNs) are machine-learning–based computational models that visualize causal relationships and provide insight into the processes underlying disease progression, closely resembling clinical decision-making. Preoperative identification of patients at risk for lymph node metastasis (LNM) is challenging in endometrial cancer, and although several biomarkers are related to LNM, none of them are incorporated in clinical practice. The aim of this study was to develop and externally validate a preoperative BN to predict LNM and outcome in endometrial cancer patients. Methods and findings: Within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC), we performed a retrospective multicenter cohort study including 763 patients, median age 65 years (interquartile range [IQR] 58–71), surgically treated for endometrial cancer between February 1995 and August 2013 at one of the 10 participating European hospitals. A BN was developed using score-based machine learning in addition to expert knowledge. Our main outcome measures were LNM and 5-year disease-specific survival (DSS). Preoperative clinical, histopathological, and molecular biomarkers were included in the network. External validation was performed using 2 prospective study cohorts: the Molecular Markers in Treatment in Endometrial Cancer (MoMaTEC) study cohort, including 446 Norwegian patients, median age 64 years (IQR 59–74), treated between May 2001 and 2010; and the PIpelle Prospective ENDOmetrial carcinoma (PIPENDO) study cohort, including 384 Dutch patients, median age 66 years (IQR 60–73), treated between September 2011 and December 2013. A BN called ENDORISK (preoperative risk stratification in endometrial cancer) was developed including the following predictors: preoperative tumor grade; immunohistochemical expression of estrogen receptor (ER), progesterone receptor (PR), p53, and L1 cell adhesion molecule (L1CAM); cancer antigen 125 serum level; thrombocyte count; imaging results on lymphadenopathy; and cervical cytology. In the MoMaTEC cohort, the area under the curve (AUC) was 0.82 (95% confidence interval [CI] 0.76–0.88) for LNM and 0.82 (95% CI 0.77–0.87) for 5-year DSS. In the PIPENDO cohort, the AUC for 5-year DSS was 0.84 (95% CI 0.78–0.90). The network was well-calibrated. In the MoMaTEC cohort, 249 patients (55.8%) were classified with <5% risk of LNM, with a false-negative rate of 1.6%. A limitation of the study is the use of imputation to correct for missing predictor variables in the development cohort and the retrospective study design. Conclusions: In this study, we illustrated how BNs can be used for individualizing clinical decision-making in oncology by incorporating easily accessible and multimodal biomarkers. The network shows the complex interactions underlying the carcinogenetic process of endometrial cancer by its graphical representation. A prospective feasibility study will be needed prior to implementation in the clinic. Casper Reijnen and co-workers report on risk prediction in endometrial cancer. Author summary: Why was this study done?: Bayesian networks are graphical networks that are based on machine learning and can be used for prediction purposes without the need to have values for all predictor variables available for each patient. Approximately 10% of patients with endometrial cancer have lymph node metastasis. The risk of lymph node metastasis and poor outcome differs substantially between individuals. Preoperative identification of patients at risk for lymph node metastasis and poor outcome allows tailoring of individualized treatment. What did the researched do and find?: A Bayesian network to predict the risk of lymph node metastasis and survival was constructed with data from a retrospective multicenter development cohort from 10 centers across Europe (n = 763). The predictive capability of the final network was tested in 2 external cohorts from the Netherlands (PIpelle Prospective ENDOmetrial carcinoma [PIPENDO], n = 384) and from Norway (Molecular Markers in Treatment in Endometrial Cancer [MoMaTEC], n = 446). What do these findings mean?: The Bayesian network we propose allows refined risk stratification before surgery and is easily usable. Because of its graphical character, the interactions between the different variables included into the network are directly visualized. A prospective feasibility study will be needed prior to implementation in the clinic. [ABSTRACT FROM AUTHOR]