title: Systematic review and meta-analysis comparing the surgical outcomes of invasive intraductal papillary mucinous neoplasms and conventional pancreatic ductal adenocarcinoma.
abstract: OBJECTIVE
  The aim of this study was to summarize the current literature comparing the surgical outcomes of invasive intraductal papillary mucinous neoplasms (IPMN(INV)) and conventional pancreatic ductal adenocarcinomas (PDAC) in order to determine the differences in disease characteristics and prognosis.
  
  
  METHODS
  Systematic review of the literature yielded 12 comparative studies reporting the clinicopathological characteristics and overall survival (OS) of 1,450 patients with IPMN(INV) with 19,304 patients with conventional PDAC.
  
  
  RESULTS
  IPMN(INV) had a significantly lower likelihood of tumors extending beyond the pancreas [27.6 vs. 94.3 %; T4 vs. T1: odds ratio (OR) 0.111, 95 % confidence intervals (CI) 0.057-0.214], nodal metastasis (45.4 vs. 62.9 %: OR 0.507, 95 % CI 0.347-0.741), positive margin (14.2 vs. 28.3 %; OR 0.438, 95 % CI 0.322-0.596), perineural invasion (49.2 vs. 76.5 %; OR 0.304, 95 % CI 0.106-0.877) and vascular invasion (25.2 vs. 45.7 % OR 0.417, 95 % CI 0.177-0.980) when compared with PDAC. The 5-year OS of IPMN(INV) was significantly better than PDAC [31.4 vs. 12.4 %: hazard ratio (HR) 0.659, 95 % CI 0.574-0.756]. The tubular subtype had a poorer 5-year OS and demonstrated significantly more aggressive features such as nodal metastases, vascular invasion, and perineural invasion compared with the colloid subtype.
  
  
  CONCLUSIONS
  IPMN(INV) were significantly more likely to present at an earlier stage and were less likely to demonstrate nodal involvement, perineural invasion and vascular invasion. When controlled for stage, IPMN(INV) had an improved OS when compared with PDAC in the early stages.
authors.affiliation: Department of Hepatopancreatobiliary and Transplant Surgery, Division of Surgery, Singapore General Hospital, Singapore, Singapore.
authors.forename: Ye-Xin
authors.initials: YX
authors.lastname: Koh
authors.forename: Aik-Yong
authors.initials: AY
authors.lastname: Chok
authors.forename: Hui-Li
authors.initials: HL
authors.lastname: Zheng
authors.forename: Chuen-Seng
authors.initials: CS
authors.lastname: Tan
authors.forename: Brian K P
authors.initials: BK
authors.lastname: Goh
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology / Q000601:surgery*; D021441:Carcinoma, Pancreatic Ductal / Q000473:pathology / Q000601:surgery*; D002291:Carcinoma, Papillary / Q000473:pathology / Q000601:surgery*; D006801:Humans; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000601:surgery*; D011379:Prognosis