THE PNEUMOPERITONEUM AND ITS ROLE IN TUMOR SEEDING

Port site recurrences (PSR) ere abdominal wall recurrences that occur within a trocar site after cancer laparoscopy and that are not associa ted with peritoneal carcinosis. The short clinical delay of occurrence of PSR (median 190 days in colorectal cancer) suggests a massive cell seeding into the abdominal wall(over 10(6) cells) during the operatio n. In human and animal studies, CO2 was not able to aerosolize large n umbers of tumor cells using pressures of 8-15 mm Hg, even though isola ted mesothelial cells have been found in the aerosol. Such large numbe rs of tumor cells have only been demonstrated on instruments and troca rs. PSR occur not only after CO2 laparoscopy, but also after thoracosc opy, where no CO2 is used. Gaseless laparoscopy was able to reduce, bu t not to eliminate port site contamination in animal models. Tumor gro wth was enhanced in numerous animal models using CO2, suggesting an ad juvant effect on tumor growth in the trocar wound. Nevertheless, repor ted clinical incidences between 0 and 21% suggest that PSR might be a surgeon-related variable dependent mainly on experience and technical expertise. Technical measures have been proposed that might reduce the incidence of PSR.