title: Positive para-aortic lymph nodes following pancreatectomy for pancreatic cancer. Systematic review and meta-analysis of impact on short term survival and association with clinicopathologic features.
abstract: The relation between para-aortic lymph nodes (PALN) involvement and pancreatic ductal adenocarcinoma (PDAC) survival, along with the optimal handling of this particular lymph node station remain unclear. A systematic review and meta-analysis was performed to assess this.
  
  
  
  A search of Medline, Embase, Ovid and Cochrane databases was performed until July 2015 to identify studies reporting on the relation of PALN involvement and PDAC outcomes and a meta-analysis was performed following data extraction.
  
  
  
  Ten retrospective studies and two prospective non randomized studies (2467 patients) were included. Patients with positive PALN had worse one (p < 0.00001) and two year (p < 0.00001) survival when compared with patients with negative PALN. Even when comparing only patients with positive lymph nodes (N1), patients with PALN involvement presented with a significant lower one (p = 0.03) and two (p = 0.002) year survival. PALN involvement was associated with an increased possibility of positive margin (R1) resection (p < 0.00001), stations' 12, 14 and 17 malignant infiltration (p < 0.00001), but not with tumour stage (p = 0.78).
  
  
  
  Involvement of PALN is associated with decreased survival in pancreatic cancer patients. However, existence of long term survivors among this subgroup of patients should be further evaluated, in order to identify factors associated with their favourable prognosis.
authors.affiliation: Athens Naval and Veterans Hospital, Department of Surgery, Athens, Greece. Electronic address: xagali@gmail.com.
authors.forename: Christos
authors.initials: C
authors.lastname: Agalianos
authors.affiliation: "Konstantopouleio" Hospital of Athens, Department of Surgery, Athens, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Gouvas
authors.affiliation: "Konstantopouleio" Hospital of Athens, Department of Pathology, Athens, Greece.
authors.forename: Kleo
authors.initials: K
authors.lastname: Papaparaskeva
authors.affiliation: "Konstantopouleio" Hospital of Athens, Department of Surgery, Athens, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Dervenis
mesh_terms: D021441:Carcinoma, Pancreatic Ductal / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D000072662:Margins of Excision; D008875:Middle Aged; D009367:Neoplasm Staging; D018365:Neoplasm, Residual; D016017:Odds Ratio; D010180:Pancreatectomy / Q000009:adverse effects / Q000401:mortality; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D018570:Risk Assessment; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome