Pathology remains the most important predictor of long-term survival using a modern prognostic nomogram for resected pancreatic ductal adenocarcinoma

Abstract

Background: Our group previously published a prognostic nomogram generated from data on 555 patients resected between 1983 and 2000. Improvements in perioperative outcomes, and application of modern chemotherapy regimens, may have influenced the importance of certain prognostic variables. The purpose of this study was to re-evaluate prognostic variables for patients undergoing resection for pancreatic ductal adenocarcinoma (PDAC) using a contemporary dataset, and generate a predictive model for long-term survival. Methods: A prospectively maintained pancreas registry at Memorial Sloan Kettering was analyzed from 2000–2016, identifying patients that underwent pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) for pancreatic ductal adenocarcinoma. Patients with mortality within 90 days of resection were excluded. Patient, tumor, and treatment related variables were analyzed for their association with the primary endpoint of overall survival (OS). A nomogram was generated using univariate and multivariate regression, and cubic splines were used for continuous variables. Survival was predicted at 1, 3, and 5 years after resection. Results: 1,322 patients met inclusion criteria, from which 927 patients were used to build the model and 395 patients were used for validation. Median patient age was 69 years (range = 30–91 years) with equal gender distribution (51% male, 49% female). Pancreaticoduodenectomy was performed in 1,052 (80%) patients and 270 (20%) underwent distal pancreatectomy. Positive margins were found in 26% of patients, and 68% had positive lymph nodes. Median estimated blood loss (EBL) was 500 mL (range = 20–8,500 mL), length of stay was 8 days (range = 3–162 days), and the overall grade 3 or 4 complication rate was 22% (23% after PD and 18% after DP). Univariate analysis revealed increasing age (HR 1.02), increasing tumor size (HR 1.01), positive margins (HR 1.48), positive lymph nodes (HR 1.79), increasing number of positive lymph nodes (HR 1.07 per node), and EBL (HR 1.02 per 100 mL) to be associated with OS. Multivariate analysis concluded that age, tumor size, margin status, the number of positive lymph nodes, and EBL were predictive of OS, and were included in the nomogram (Figure), for which the concordance index was 0.62. Conclusion: Using a large, prospectively maintained registry of patients undergoing resection for PDAC, a nomogram prognostic of 1-, 3-, and 5-year survival was generated. Criteria for pathologic staging, namely tumor size and nodal burden, remain the most important predictors of long-term survival.