title: Disease-free survival after complete mesocolic excision compared with conventional colon cancer surgery: a retrospective, population-based study.
abstract: BACKGROUND
  Application of the principles of total mesorectal excision to colon cancer by undertaking complete mesocolic excision (CME) has been proposed to improve oncological outcomes. We aimed to investigate whether implementation of CME improved disease-free survival compared with conventional colon resection.
  
  
  METHODS
  Data for all patients who underwent elective resection for Union for International Cancer Control (UICC) stage I-III colon adenocarcinomas in the Capital Region of Denmark between June 1, 2008, and Dec 31, 2011, were retrieved for this population-based study. The CME group consisted of patients who underwent CME surgery in a centre validated to perform such surgery; the control group consisted of patients undergoing conventional colon resection in three other hospitals. Data were collected from the Danish Colorectal Cancer Group (DCCG) database and medical charts. Patients were excluded if they had stage IV disease, metachronous colorectal cancer, rectal cancer (≤ 15 cm from anal verge) in the absence of synchronous colon adenocarcinoma, tumour of the appendix, or R2 resections. Survival data were collected on Nov 13, 2014, from the DCCG database, which is continuously updated by the National Central Office of Civil Registration.
  
  
  RESULTS
  The CME group consisted of 364 patients and the non-CME group consisted of 1031 patients. For all patients, 4-year disease-free survival was 85.8% (95% CI 81.4-90.1) after CME and 75.9% (72.2-79.7) after non-CME surgery (log-rank p=0.0010). 4-year disease-free survival for patients with UICC stage I disease in the CME group was 100% compared with 89.8% (83.1-96.6) in the non-CME group (log-rank p=0.046). For patients with UICC stage II disease, 4-year disease-free survival was 91.9% (95% CI 87.2-96.6) in the CME group compared with 77.9% (71.6-84.1) in the non-CME group (log-rank p=0.0033), and for patients with UICC stage III disease, it was 73.5% (63.6-83.5) in the CME group compared with 67.5% (61.8-73.2) in the non-CME group (log-rank p=0.13). Multivariable Cox regression showed that CME surgery was a significant, independent predictive factor for higher disease-free survival for all patients (hazard ratio 0.59, 95% CI 0.42-0.83), and also for patients with UICC stage II (0.44, 0.23-0.86) and stage III disease (0.64, 0.42-1.00). After propensity score matching, disease-free survival was significantly higher after CME, irrespective of UICC stage, with 4-year disease-free survival of 85.8% (95% CI 81.4-90.1) after CME and 73.4% (66.2-80.6) after non-CME (log-rank p=0·0014).
  
  
  CONCLUSIONS
  Our data indicate that CME surgery is associated with better disease-free survival than is conventional colon cancer resection for patients with stage I-III colon adenocarcinoma. Implementation of CME surgery might improve outcomes for patients with colon cancer.
  
  
  BACKGROUND
  Tvergaards Fund and Edgar and Hustru Gilberte Schnohrs Fund.
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark. Electronic address: cabertelsen@gmail.com.
authors.forename: Claus Anders
authors.initials: CA
authors.lastname: Bertelsen
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders Ulrich
authors.initials: AU
authors.lastname: Neuenschwander
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jens Erik
authors.initials: JE
authors.lastname: Jansen
authors.affiliation: Department of Surgical Gastroenterology, Hvidovre University Hospital, Hvidovre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Wilhelmsen
authors.affiliation: Department of Surgery, Herlev University Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Kirkegaard-Klitbo
authors.affiliation: Department of Surgery, Bispebjerg University Hospital, København NV, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jutaka Reilin
authors.initials: JR
authors.lastname: Tenma
authors.affiliation: Department of Pathology, Herlev University Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Bols
authors.affiliation: Department of Pathology, Herlev University Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Ingeholm
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Leif Ahrenst
authors.initials: LA
authors.lastname: Rasmussen
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Lars Vedel
authors.initials: LV
authors.lastname: Jepsen
authors.affiliation: Department of Surgery, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Else Refsgaard
authors.initials: ER
authors.lastname: Iversen
authors.affiliation: Department of Clinical Physiology, Hillerød University Hospital, Hillerød, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Bent
authors.initials: B
authors.lastname: Kristensen
authors.affiliation: Department of Surgery, Køge Roskilde University Hospital, Køge, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Ismail
authors.initials: I
authors.lastname: Gögenur
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D000368:Aged; D018276:Carcinoma, Medullary / Q000453:epidemiology / Q000401:mortality* / Q000556:secondary / Q000601:surgery*; D018279:Carcinoma, Signet Ring Cell / Q000453:epidemiology / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D003718:Denmark / Q000453:epidemiology; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008646:Mesocolon / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate