title: Influence of Individual Surgeon Volume on Oncological Outcome of Colorectal Cancer Surgery.
abstract: BACKGROUND
  Surgery performed by a high-volume surgeon improves short-term outcomes. However, not much is known about long-term effects. Therefore we performed the current study to evaluate the impact of high-volume colorectal surgeons on survival.
  
  
  METHODS
  We conducted a retrospective analysis of our prospectively collected colorectal cancer database between 2004 and 2011. Patients were divided into two groups: operated on by a high-volume surgeon (>25 cases/year) or by a low-volume surgeon (<25 cases/year). Perioperative data were collected as well as follow-up, recurrence rates, and survival data.
  
  
  RESULTS
  774 patients underwent resection for colorectal malignancies. Thirteen low-volume surgeons operated on 453 patients and 4 high-volume surgeons operated on 321 patients. Groups showed an equal distribution for preoperative characteristics, except a higher ASA-classification in the low-volume group. A high-volume surgeon proved to be an independent prognostic factor for disease-free survival in the multivariate analysis (P = 0.04). Although overall survival did show a significant difference in the univariate analysis (P < 0.001) it failed to reach statistical significance in the multivariate analysis (P = 0.09).
  
  
  CONCLUSIONS
  In our study, a higher number of colorectal cases performed per surgeon were associated with longer disease-free survival. Implementing high-volume surgery results in improved long-term outcome following colorectal cancer.
authors.affiliation: Department of Surgery, Alrijne Hospital, Location Leiderdorp, Simon Smitweg 1, 2353 GA Leiderdorp, Netherlands.
authors.forename: Marleen
authors.initials: M
authors.lastname: Buurma
authors.affiliation: Department of Surgery, Alrijne Hospital, Location Leiderdorp, Simon Smitweg 1, 2353 GA Leiderdorp, Netherlands.
authors.forename: Hidde M
authors.initials: HM
authors.lastname: Kroon
authors.affiliation: Department of Surgery, Alrijne Hospital, Location Leiderdorp, Simon Smitweg 1, 2353 GA Leiderdorp, Netherlands ; Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, Netherlands.
authors.forename: Marlies S
authors.initials: MS
authors.lastname: Reimers
authors.affiliation: Department of Surgery, Alrijne Hospital, Location Leiderdorp, Simon Smitweg 1, 2353 GA Leiderdorp, Netherlands.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Neijenhuis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000532:radiotherapy / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D009426:Netherlands / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D066231:Surgeons / Q000706:statistics & numerical data*; D016896:Treatment Outcome