Neoadjuvant Therapy for Invasive Intraductal Papillary Mucinous Neoplasms: A Comparative Study With Pancreatic Ductal Adenocarcinoma.

[BACKGROUND] Invasive intraductal papillary mucinous neoplasms (I-IPMNs) are considered more indolent than conventional pancreatic ductal adenocarcinoma (PDAC). Although neoadjuvant therapy (NAT) is widely adopted in PDAC, its role in I-IPMN remains unclear. This study aimed to evaluate the impact of NAT on survival in I-IPMN compared with PDAC.

[METHODS] The study enrolled I-IPMN and PDAC patients undergoing resection at the University of Colorado Hospital between 2013 and 2023. Prognostic factors for overall survival (OS) were identified using Cox models. OS was compared between histology/NAT subgroups using the Kaplan-Meier method and the log-rank test, stratified by resectability.

[RESULTS] Of 500 patients (413 PDAC, 87 I-IPMN), 289 PDAC and 34 I-IPMN patients received NAT, and the I-IPMN patients showed slightly longer median OS than the PDAC patients (30.2 vs 28.1 months; p = 0.04). In the entire cohort, worse OS was associated with borderline resectable (BR)/locally advanced (LA) disease, elevated cancer antigen 19-9 (CA19-9), node-positive disease, lymphovascular invasion, perineural invasion, and absence of adjuvant therapy. In the resectable cohort (n = 311), NAT was associated with longer OS in PDAC (61.9 vs 34.2 months; p < 0.001), but not in I-IPMN (not reached vs 47.9 months; p = 0.74). Survival did not differ between NAT-treated resectable I-IPMN and PDAC (p = 0.95). In the BR/LA cohort treated with NAT (n = 183), OS was similar between I-IPMN and PDAC (17.1 vs 22.0 months; p = 0.69).

[CONCLUSIONS] In resectable I-IPMN, NAT was not associated with improved survival. Comparable survival between NAT-treated BR/LA I-IPMN and PDAC suggests a need for further research on treatment outcomes.