title: Simultaneous resection of primary colorectal cancer and synchronous liver metastases: a population-based study.
abstract: BACKGROUND
  Simultaneous resection of primary colorectal cancer (CRC) and synchronous liver metastases (LM) is gaining interest. We describe management and outcomes of patients undergoing simultaneous resection in the general population.
  
  
  METHODS
  All patients with CRC who underwent surgical resection of LM between 2002 and 2009 were identified using the population-based Ontario Cancer Registry and linked electronic treatment records. Synchronous disease was defined as having resection of CRCLM within 12 weeks of surgery for the primary tumour.
  
  
  RESULTS
  During the study period, 1310 patients underwent resection of CRCLM. Of these, 226 (17%) patients had synchronous disease; 100 (44%) had a simultaneous resection and 126 (56%) had a staged resection. For the simultaneous and the staged groups, the mean number of liver lesions resected was 1.6 and 2.3, respectively (p< 0.001); the mean size of the largest lesion was 3.1 and 4.8 cm, respectively (p< 0.001); and the major hepatic resection rate was 21% and 79%, respectively (p< 0.001). Postoperative mortality for simultaneous cases at 90 days was less than 5%. Five-year overall survival and cancer-specific survival for patients with simultaneous resection was 36% (95% confidence interval [CI] 26%-45%) and 37% (95% CI 25%-50%), respectively. Simultaneous resections are common in the general population. A more conservative approach is being adopted for simultaneous resections by limiting the extent of liver resection. Postoperative mortality and long-term survival in this patient population is similar to that reported in other contemporary series.
  
  
  CONCLUSIONS
  Compared with a staged approach, patients undergoing simultaneous resections had fewer and smaller liver metastases and underwent less aggressive resections. One-third of these patients achieved long-term survival.
authors.affiliation: From the Department of Surgery, Queen's University, Kingston, Ont., (Nanji); the Department of Oncology, Queen's University, Kingston, Ont., (Nanji, Mackillop, Booth); the Department of Public Health, Queen's University, Kingston, Ont., (Mackillop, Wei, Booth); and the Division of Cancer Care and Epidemiology, Cancer Research Institute, Queen's University, Kingston, Ont., (Mackillop, Booth).
authors.forename: Sulaiman
authors.initials: S
authors.lastname: Nanji
authors.affiliation: From the Department of Surgery, Queen's University, Kingston, Ont., (Nanji); the Department of Oncology, Queen's University, Kingston, Ont., (Nanji, Mackillop, Booth); the Department of Public Health, Queen's University, Kingston, Ont., (Mackillop, Wei, Booth); and the Division of Cancer Care and Epidemiology, Cancer Research Institute, Queen's University, Kingston, Ont., (Mackillop, Booth).
authors.forename: William J
authors.initials: WJ
authors.lastname: Mackillop
authors.affiliation: From the Department of Surgery, Queen's University, Kingston, Ont., (Nanji); the Department of Oncology, Queen's University, Kingston, Ont., (Nanji, Mackillop, Booth); the Department of Public Health, Queen's University, Kingston, Ont., (Mackillop, Wei, Booth); and the Division of Cancer Care and Epidemiology, Cancer Research Institute, Queen's University, Kingston, Ont., (Mackillop, Booth).
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Wei
authors.affiliation: From the Department of Surgery, Queen's University, Kingston, Ont., (Nanji); the Department of Oncology, Queen's University, Kingston, Ont., (Nanji, Mackillop, Booth); the Department of Public Health, Queen's University, Kingston, Ont., (Mackillop, Wei, Booth); and the Division of Cancer Care and Epidemiology, Cancer Research Institute, Queen's University, Kingston, Ont., (Mackillop, Booth).
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Booth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy / Q000379:methods / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006498:Hepatectomy / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010043:Outcome and Process Assessment, Health Care / Q000706:statistics & numerical data; D012042:Registries; D012189:Retrospective Studies; D055815:Young Adult