title: The incidence of port-site metastases might be reduced.
abstract: BACKGROUND
  Laparoscopic resection for cancer is controversial and port-site metastases are not infrequent. The mechanisms of occurrence of port-site metastases remain unclear. Animal experiments have suggested a role for carbon dioxide (CO2), but port-site metastases also occur after thoracoscopy, where no CO2 is used. The aim of this study was to define the role of CO2 in the seeding of tumor cells in the human patient.
  
  
  METHODS
  CO2, instruments, trocars, suction device, and peritoneal washing were examined during 12 staging laparoscopies for pancreatic cancer. The presence, viability, and biological significance of cells were investigated using conventional cytology, polymerase chain reaction (PCR), and restriction fragment length polymorphisms (RFLPs) to detect the presence of a mutant k-ras gene as a genetic marker of cancer cells.
  
  
  RESULTS
  Cytology exam of peritoneal washing, instruments, the suction device, and trocars revealed many cells. Tumor cells were detected in 6/12 peritoneal, in 4/12 trocars and 4/11 instruments washings, but not in 12 CO2 samples. The DNA content of CO2 was very low-as assessed by PCR. Mutant DNA was detected by RFLP in four out of 12 aerosols. Six aerosols did not contain any DNA. Two aerosols were borderline.
  
  
  CONCLUSIONS
  During staging laparoscopy for pancreatic cancer in humans, CO2 contains only very low levels of free-floating tumor cells, even in the presence of massive peritoneal contamination. These results suggest that the incidence of port-site metastases might be reduced if mechanical contamination of the port sites with instruments or with the specimen can be avoided.
authors.affiliation: Department of Surgery, University of Erlangen, P.O. Box 3560, 91023 Erlangen, Germany.
authors.forename: M A
authors.initials: MA
authors.lastname: Reymond
authors.forename: C
authors.initials: C
authors.lastname: Wittekind
authors.forename: A
authors.initials: A
authors.lastname: Jung
authors.forename: W
authors.initials: W
authors.lastname: Hohenberger
authors.forename: T
authors.initials: T
authors.lastname: Kirchner
authors.forename: F
authors.initials: F
authors.lastname: Köckerling
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000517:prevention & control / Q000556:secondary*; D001483:Base Sequence; D002245:Carbon Dioxide / Q000032:analysis; D004273:DNA, Neoplasm / Q000032:analysis; D004869:Equipment Safety; D006801:Humans; D020706:Laparoscopes; D010535:Laparoscopy / Q000009:adverse effects*; D008969:Molecular Sequence Data; D009362:Neoplasm Metastasis / Q000517:prevention & control; D009366:Neoplasm Seeding; D009367:Neoplasm Staging / Q000009:adverse effects* / Q000379:methods; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000517:prevention & control; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D004273:DNA, Neoplasm; D002245:Carbon Dioxide