Development and validation of a nomogram for overall survival in pancreatic solid pseudopapillary neoplasm: a population-based study

Solid pseudopapillary neoplasm (SPN) of the pancreas is an uncommon tumor, leading to the lack of a prognostic prediction model. This study aimed to develop and validate a nomogram for predicting overall survival (OS) in SPN patients. Data from patients diagnosed with SPN between 2000 and 2018 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database and randomly split into training and validation cohorts (7:3). Independent prognostic factors for OS were identified by Cox regression analysis. A nomogram was constructed and internally validated using the concordance index (C-index), area under the curve (AUC), calibration curves, and decision curve analysis (DCA). External validation was performed using our institutional data from SPN patients between January 2008 and January 2026. The results showed that the total positive lymph nodes, age, surgery type, and SEER summary stage were all independent prognostic factors for OS chosen to develop a nomogram for SPN. C-indices of 0.927, 0.93, and 0.965 were found in the training, internal validation, and external verification cohorts respectively. The nomogram's discriminative ability was proved by the AUC value (> 0.7), and the calibration curve showed alignment between the nomogram's prediction and actual survival. Finally, the outcomes of DCA further demonstrated the nomogram's clinical effectiveness. In conclusion, A nomogram was built and validated to help doctors to determine the prognosis of patients with SPN and tailor treatment options.