Invasive intraductal papillary mucinous neoplasm versus sporadic pancreatic adenocarcinoma: A stage-matched comparison of outcomes

BACKGROUND: Although invasive intraductal papillary mucinous neoplasm (IPMN) of the pancreas is thought to be more indolent than sporadic pancreatic adenocarcinoma (PAC), the natural history remains poorly defined. The authors compared survival and identify prognostic factors after resection for invasive IPMN versus stage-matched PAC. METHODS: The Surveillance, Epidemiology, and End Results database (1991-2005) was used to identify 729 patients with invasive IPMN and 8082 patients with PAC who underwent surgical resection. RESULTS: Patients with resected invasive IPMN experienced improved overall survival when compared with resected PAC (median survival, 21 vs 14 months; P < .001). Stratification by nodal status demonstrated no difference in survival among lymph node-positive patients; however, median survival of resected, lymph node-negative, invasive IPMN was significantly improved compared with lymph node-negative PAC (34 vs 18 months; P < .001). On multivariate analysis, PAC histology was an adverse predictor of overall survival (hazard ratio [HR], 1.31; 95% confidence interval [CI], 1.15-1.50) compared with invasive IPMN. For patients with invasive IPMN, positive lymph nodes (HR, 1.98; 95% CI, 1.50-2.60), high tumor grade (HR, 1.74; 95% CI, 1.31-2.31), tumor size >2 cm (HR, 1.50; 95% CI, 1.04-2.19), and age >66 years (HR, 1.33; 95% CI, 1.03-1.73) were adverse predictors of survival. CONCLUSIONS: Although lymph node-negative invasive IPMN showed improved survival after resection compared with lymph node-negative PAC, the natural history of lymph node-positive invasive IPMN mimicked that of lymph node-positive PAC. The authors also identified adverse predictors of survival in invasive IPMN to guide discussions regarding use of adjuvant therapies and prognosis after resection of invasive IPMN.