title: Learning curve to lymph node resection in minimally invasive esophagectomy for cancer.
abstract: OBJECTIVE
  Minimally invasive esophagectomy (MIE) is a safe alternative to open approaches, yet the impact of the minimally invasive approach on oncologic efficacy is unclear. The objectives of the current study were to compare lymph node yields and surgical margins during a single-surgeon series to examine the learning curve to oncologic aspects of MIE.
  
  
  METHODS
  A retrospective review of a prospectively maintained institutional database was performed. The sequential MIE experience for esophageal cancer was subcategorized into terciles (first 25 MIEs as early, next 24 as middle, and most recent 24 as later).
  
  
  RESULTS
  Seventy-three patients underwent MIE for cancer between 2008 and 2013. Complete resections (R0) were performed in 71 cases (93%), and there were no significant differences in the number of complete resections with negative margins during the MIE experience (P = 0.54). The number of lymph nodes harvested during MIE increased significantly with progressive experience, with a mean of 22, 29, and 28 nodes recovered in the early, middle, and late subgroups, respectively (P = 0.038). On multivariate analysis, only increasing surgeon experience (1.4-fold increase in nodal yield for the latter two thirds relative to the first third, P = 0.0011) and histology of high-grade dysplasia (0.54-fold decrease in nodal yield relative to adenocarcinoma or squamous cell carcinoma, P = 0.025) were significant predictors of lymph node yield.
  
  
  CONCLUSIONS
  The ability to execute a complete lymphadenectomy during MIE is affected by surgeon experience and improves over time, plateauing after the first 25 cases.
authors.affiliation: From the *Department of Surgery, Morristown Memorial Hospital, Morristown, NJ USA; †Section of Thoracic Surgery, and ‡Division of Medical Oncology, Department of Internal Medicine, Yale University School of Medicine; and §Department of Epidemiology, Yale School of Public Health, New Haven, CT USA.
authors.forename: Ankit
authors.initials: A
authors.lastname: Dhamija
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Rosen
authors.forename: Anish
authors.initials: A
authors.lastname: Dhamija
authors.forename: Bonnie E
authors.initials: BE
authors.lastname: Gould Rothberg
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Kim
authors.forename: Frank C
authors.initials: FC
authors.lastname: Detterbeck
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Boffa
mesh_terms: D000368:Aged; D004938:Esophageal Neoplasms / Q000601:surgery*; D016629:Esophagectomy / Q000379:methods*; D005260:Female; D006801:Humans; D059032:Learning Curve; D008197:Lymph Node Excision / Q000193:education*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D012189:Retrospective Studies