title: Rapid flow carbon dioxide laparoscopy disperses cancer cells into the peritoneal cavity but not the port sites in a new rat model.
abstract: BACKGROUND
  The role of carbon dioxide (CO2) in the pathogenesis of tumor recurrence after laparoscopy remains controversial. Using a new rat model, we studied the effect of different CO2 flow rates on the dispersal of free cancer cells.
  
  
  METHODS
  A novel model of desufflation without trocar was developed, and 55 Fischer rats were randomized into three flow groups: group A (rapid, 0.67 l/min; n = 20), group B (slow, 0.44 l/min; n = 20), and group C (gasless, n = 15). We vented CO2 via a portless surgical valve that filtered cells. After the abdominal wall had been suspended to create space, half of the animals in each group (nonrecovery) received 7.5 x 10(6) immunolabeled rat colon cancer cells (RCC2) intraperitoneally, whereas the other half (recovery) received 7.5 x l0(6) viable RCC2 before insufflation or gasless laparoscopy. Nonrecovery animals were killed after 20 l of insufflation. Parietal peritoneal and port-site specimens were examined for RCC2 by fluorescence microscopy (FM) and flow cytometry (FC). The recovery animals were killed at 4 weeks for evidence of wound recurrence.
  
  
  RESULTS
  Nine of 10 nonrecovery animals in A had RCC2 on FM or FC, as compared with 2 animals in each of the nonrecovery groups B and C (p = 0.018, Fisher's exact test). Two of the nine animals in group A also had RCC2 in their portless valves. Two recovery (A) animals developed wound recurrence as compared with none in the other groups (p = 0.315).
  
  
  CONCLUSIONS
  In this model, rapid CO2 flow dispersed free cancer cells into the peritoneal cavity, but not into the port sites, thus supporting a role for CO2 in the intraperitoneal dispersal of free cancer cells, but not in wound recurrence.
authors.affiliation: Division of Surgery, Anaesthetics and Intensive Care, Imperial College School of Medicine, Hammersmith Hospital, London, UK. kszayyan@yahoo.co.uk
authors.forename: K S
authors.initials: KS
authors.lastname: Zayyan
authors.forename: J S
authors.initials: JS
authors.lastname: Christie-Brown
authors.forename: S
authors.initials: S
authors.lastname: Van Noorden
authors.forename: C-Y
authors.initials: CY
authors.lastname: Yiu
authors.forename: D P
authors.initials: DP
authors.lastname: Sellu
authors.forename: R T
authors.initials: RT
authors.lastname: Mathie
mesh_terms: D000008:Abdominal Neoplasms / Q000601:surgery*; D000818:Animals; D002245:Carbon Dioxide / Q000009:adverse effects; D002470:Cell Survival; D003110:Colonic Neoplasms / Q000628:therapy; D004195:Disease Models, Animal; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000209:etiology*; D009366:Neoplasm Seeding; D009368:Neoplasm Transplantation; D010534:Peritoneal Neoplasms / Q000209:etiology* / Q000473:pathology*; D010865:Pilot Projects; D011677:Punctures / Q000009:adverse effects; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D002245:Carbon Dioxide