Invasive IPMN and MCN: same organ, different outcomes?

BACKGROUND

The efficacy of surgery for invasive mucinous neoplasms is unclear. We examined the natural history of invasive mucinous cystic neoplasms (MCN) and invasive intraductal papillary mucinous neoplasms (IPMN) in patients who underwent pancreatic resection.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1996-2006) was queried for cases of resected invasive MCN and IPMN. Demographics, tumor characteristics, and overall survival were examined using log-rank analysis and multivariate Cox regression model.

RESULTS

Of 185 MCN cases and 641 IPMN cases, 73% and 48%, respectively, were women (P < 0.0001). Most (73%) IPMN were in the head of the pancreas; most (64%) MCN were in the tail/body (P < 0.0001). Lymph node metastasis was more common for IPMN than MCN (46% vs. 24%, P < 0.0001). Overall survival after resection was better for patients with stage I MCN vs. stage I IPMN (P = 0.0005), and it was better for patients with node-negative MCN vs. node-negative IPMN (P = 0.0061). There was no significant difference in survival of patients with stage IIA MCN vs. stage IIA IPMN (P = 0.5964), stage IIB MCN vs. stage IIB IPMN (P = 0.2262), or node-positive MCN vs. node-positive IPMN (P = 0.2263). Age older than 65 years (hazards ratio (HR) 1.71, P = 0.0046), high tumor grade (HR 2.68, P < 0.0001), higher T stage (HR 2.11, P < 0.0001), and IPMN histology (HR 1.90, P = 0.0040) predicted worse outcome in node-negative patients.

CONCLUSIONS

Our findings suggest that survival is better after resection of invasive MCN versus invasive IPMN when disease is localized within the pancreas, but this difference disappears in the presence of nodal metastasis or extrapancreatic extension.