Invasive pancreatic cystic neoplasm with favorable prognosis: A large retrospective cohort study over two decades

Abstract Purposes: Invasive pancreatic cystic neoplasms (iPCNs) are an uncommon and biologically heterogeneous group of aggressive neoplasms. We aimed to investigate the clinicopathological characteristics of iPCN patients, and to develop nomograms for individual survival prediction after radical surgery. Methods: Data of patients diagnosed with iPCN between 2000 and 2018 from the SEER database were retrieved. The differences of clinical outcomes were evaluated using Kaplan-Meier analysis. Nomograms were proposed based on Cox regression model and internally validated by C-index, AUC value, and calibration plot. Results: A total of 7777 iPCN patients were enrolled. Most neoplasms were advanced, with 63.1% at stage IV. The 3-year OS and CSS rates in surgical patients were as follows: 45.7% and 50.1% for invasive IPMN, 54.8% and 59.3% for invasive MCN, 97.8% and 98.2% for invasive SPN, 88.9% and 88.9% for invasive SCN. Subgroup analyses showed no clinical benefit from chemotherapy or radiotherapy in lymph node-negative iPCN patients who underwent surgery. The following variables associated with OS and CSS were identified: age, race, chemotherapy, radiotherapy, histologic type, pathological grade, regional nodes examined, and T, N, and M stage. The nomograms had good discrimination and calibration by internal validation, with AUC value of 0.800 for 3-year OS and 0.814 for 3-year CSS. Conclusion: Our study showed that the prognosis of iPCN patients was significantly better than PDAC patients. The proposed nomograms demonstrated substantially better discrimination and calibration.