Survival after resection for invasive intraductal papillary mucinous neoplasm and for pancreatic adenocarcinoma: a multi-institutional comparison according to American Joint Committee on Cancer Stage.

BACKGROUND: Survival after resection for invasive intraductal papillary mucinous neoplasm (inv-IPMN) is superior to pancreatic ductal adenocarcinoma (PDAC). This difference may be explained by earlier presentation of inv-IPMN. We hypothesized that inv-IPMN has survival comparable with PDAC after resection when matched by stage. STUDY
DESIGN: From 1999 to 2009, 113 patients underwent resection for inv-IPMN at 2 large academic institutions. These data were compared with 845 patients during the same period undergoing resection for PDAC. Demographics, pathology, and overall survival (OS) were compared according to current American Joint Committee on Cancer stage.
RESULTS: Mean age with inv-IPMN and PDAC was 68 and 65 years, respectively. Follow-up was 33 and 24 months for inv-IPMN and PDAC, respectively. Median OS was 32 months for inv-IPMN and 17 months in PDAC (p < 0.001). Median OS in lymph node-negative inv-IPMN was 41 months and 24 months in PDAC (p = 0.003), with the greatest absolute difference in stage Ia patients with OS of 80 and 50 months in inv-IPMN and PDAC, respectively (p = 0.03). In node-positive patients, OS was 20 months in inv-IPMN and 15 months in PDAC (p = 0.06). Of inv-IPMN, 24% was colloid versus 75% of tubular subtype; 37(85%) of node-positive inv-IPMN were tubular subtype. Median OS was 23 and 127 months for tubular and colloid subtypes, respectively (p < 0.001).
CONCLUSIONS: When matched by stage, inv-IPMN has superior survival after resection compared with PDAC. This disparity is greatest in node-negative and least in node-positive disease. These findings suggest the behaviors of inv-IPMN and PDAC, although different, converge with advancing American Joint Committee on Cancer stage because of a greater proportion of tubular subtype.