THE INCIDENCE OF PORT-SITE METASTASES MIGHT BE REDUCED

Background: Laparoscopic resection for cancer is controversial and por t-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 pat ient. Methods: CO2, instruments, trocars, suction device, and peritone al washing were examined during 12 staging laparoscopies for pancreati c cancer. The presence, viability, and biological significance of cell s were investigated using conventional cytology, polymerase chain reac tion (PCR), and restriction fragment length polymorphisms (RFLPs) to d etect the presence of a mutant k-ras gene as a genetic marker of cance r cells. Results: Cytology exam of peritoneal washing, instruments, th e suction device, and trocars revealed many cells. Tumor cells were de tected in 6/12 peritoneal, in 4/12 trocars and 4/11 instruments washin gs, 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 aer osols. Six aerosols did not contain any DNA, Two aerosols were borderl ine. 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 resu lts suggest that the incidence of port-site metastases might be reduce d if mechanical contamination of the port sites with instruments or wi th the specimen can be avoided.