Prognostic Nomogram For Resected Pancreatic Adenocarcinoma

Objective:To identify possible prognostic factors in PC patients after radical resection,and to develop a prognostic nomogram based on independent survival predictors.Method:From 2009 to 2014,a total of 435 PC patients underwent curative intended surgeries with complete followed-up data(81.9%of all radical cases)were included in the retrospective survival analysis.Clinicopathological data were extracted from medical records and missing values were imputed 5 times with"pmm" method.Cox proportional hazards models were utilized.Data analysis was performed by using SPSS24.0.A nomogram was then formulated based on results from multivariate regression model to predict OS at 12,24,36-months and median OS.Validations including discrimination and calibration were earried out with 500 bootstrap resamples.Results:After a median 37 months of follow-ups,338 patients(77.7%)died.Median OS was 15.0 months(95%CI:13.0-17.0 months).The cumulative l-,3-,5-year OS rate were 62.3%,21.3%,12.6%,respectively.Preoperative neutrophil-lymphocyte ratio,preoperative CA19-9(log2),tumor di:fferentiation,maximal diameter,microscopic nerve invasion,microscopic vascular invasion,T stage,positive nodal ratio,M stage,and adjuvant chemotherapy were independent predictive factors for patients' OS.Bootstrap-corrected concordance-index was 0.69.The nomogram predictions discriminated better than did the AJCC stage(0.69 vs 0.54,P<0.001).And Calibration between observed and corrected is good,and variables not conventionally associated with standard staging systems improved the predictivity of the model.Conclusion:Preoperative neutrophil-lymphocyte ratio,preoperative CA19-9(log2),tumor differentiation,maximal diameter,microscopic nerve invasion,microscopic vascular invasion,T stage,positive nodal ratio,M stage,and adjuvant chemotherapy were independent predictive factors for patients' OS.Adjuvant chemotherapy should be encouraged to be done as it can significantly prolong survival time of pancreatic cancer after intended resection.Our prognostic nomogram based on clinicopathological parameters shows a good performance in predictivity,and can guide doctors and patients to choose the appropriate therapy.