Development and Validation of a Nomogram to Predict Liver Metastasis in Patients with Pancreatic Ductal Adenocarcinoma: A Large Cohort Study

Abstract

Background: Liver metastasis is an important factor which is related to treatment option and prognosis of patients with pancreatic ductal adenocarcinoma (PDAC). The association between clinipathological factors of patients and liver metastasis remains unclear. The aim of this study was to develop and validate a nomogram to predict liver metastasis in patients with PDAC. Methods: Patients diagnosed with PDAC between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database were retrospectively collected. Nomogram for predicting liver metastasis was established based on logistic regression model. The precision of the nomogram was evaluated and compared using concordance index (C-index) and the area under receiver operating characteristic curve (AUC). The clinical use of nomogram was evaluated by decision curve analysis (DCA). Findings: A total of 12644 eligible patients were divided randomly into training (n=9483) and validation cohorts (n=3161). After multivariate analysis, age, gender, tumor site, tumor grade, tumor size, lymph node (LN) metastasis, lung metastasis and bone metastasis were identified as independent predictors and included to construct nomograms. The nomograms were well calibrated, and had good discriminative ability, with C-indexes of 0.784 for the training cohort and 0.790 for validation cohort. The values of AUC for training and validation cohort were 0.792 and 0.800, respectively. Interpretation: Nomograms were constructed to predict liver metastasis in patients with PDAC. Validation revealed excellent discrimination and calibration of the nomograms, suggesting that nomograms were well calibrated and could serve to improve prediction of risks of liver metastasis and guide management of patients with PDAC. Funding Statement: This work was supported by School of Sociology and Anthropology-Sun Yat-sen University Cancer Center Joint Foundation on Medical Humanities (No. 201804, No.201816). Declaration of Interests: The authors state: No conflict of interest to declare. Ethics Approval Statement: Institutional review board approval and informed consent are not required in the current study because SEER research data is publicly available and all patient data are de-identified. All authors have signed authorization and received permission from SEER to access and use the dataset.