title: Factors predicting adequate lymph node yield in patients undergoing pancreatoduodenectomy for malignancy.
abstract: BACKGROUND
  Most pancreatoduodenectomy resections do not meet the minimum of 12 lymph nodes recommended by the American Joint Committee on Cancer for accurate staging of periampullary malignancies. The purpose of this study was to investigate factors affecting the likelihood of adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment.
  
  
  METHODS
  Six hundred sixty-two patients subject to pancreatoduodenectomy between 1990 and 2013 for pancreatic, ampullary, and common bile duct cancers were reviewed. Predictors of yielding at least 12 lymph nodes were evaluated with a logistic regression model, and a survival analysis was carried out to verify the prognostic implications of nodal counts.
  
  
  RESULTS
  The median number of evaluated nodes was 17 (interquartile range 11 to 25), and less than 12 lymph nodes were reported in surgical specimens of 179 (27 %) patients. Tumor diameter ≥20 mm (odds ratio [OR] 2.547, 95 % confidence interval [CI] 1.225 to 5.329, P = 0.013), lymph node metastases (OR 2.642, 95 % CI 1.378 to 5.061, P = 0.004), and radical lymphadenectomy (OR 5.566, 95 % CI 2.041 to 15.148, P = 0.01) were significant predictors of retrieving 12 or more lymph nodes. Lymph node counts did not influence the overall prognosis of the patients. However, a subgroup analysis carried out for individual cancer sites demonstrated that removing at least 12 lymph nodes is associated with better prognosis for pancreatic cancer.
  
  
  CONCLUSIONS
  Few variables affect adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment. Considering the ambiguities related to the only modifiable factor identified, appropriate pathology training should be considered to increase nodal yield rather than more aggressive lymphatic dissection.
authors.affiliation: First Department of Surgery, Jagiellonian University Medical College, 40 Kopernika Street, 31-501, Krakow, Poland. marek.sierzega@uj.edu.pl.
authors.forename: Marek
authors.identifier: http://orcid.org/0000-0002-7008-9026
authors.initials: M
authors.lastname: Sierzega
authors.affiliation: First Department of Surgery, Jagiellonian University Medical College, 40 Kopernika Street, 31-501, Krakow, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Bobrzyński
authors.affiliation: First Department of Surgery, Jagiellonian University Medical College, 40 Kopernika Street, 31-501, Krakow, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Matyja
authors.affiliation: First Department of Surgery, Jagiellonian University Medical College, 40 Kopernika Street, 31-501, Krakow, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Kulig
mesh_terms: D000368:Aged; D014670:Ampulla of Vater / Q000473:pathology* / Q000601:surgery; D001650:Bile Duct Neoplasms / Q000473:pathology* / Q000601:surgery; D003138:Common Bile Duct Neoplasms / Q000473:pathology* / Q000601:surgery; D004379:Duodenal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000601:surgery; D016577:Pancreaticoduodenectomy / Q000379:methods*; D017410:Practice Guidelines as Topic; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: Cancer of the ampulla of Vater; Cancer staging; Distal common bile duct cancer; Lymph nodes; Pancreatic cancer