The influence of pneumoperitoneum used in laparoscopic surgery on an intraabdominal tumor growth

BACKGROUND, Numerous clinical reports have raised the possibility that lapa roscopic cancer surgery has an inherently detrimental effect on tumor growt h. The aim of the current study was to examine the influence of a pneumoper itoneum on the morphology of the peritoneum and the intraperitoneal tumor c ell implantation and growth in the case of intraabdominal spread of tumor c ells. METHODS. Black mice were stratified into 2 groups of 36 animals each. A CO2 pneumoperitoneum was induced for 30 minutes in Group 1 and 200,000 cells o f a malignant melanoma were injected intraperitoneally. In Group 2 only tum or cells were injected. After a defined period of hours, 4 animals were kil led and the peritoneum was examined by scanning electron microscopy. RESULTS, In Group 1, starting 2 hours after release of the pneumoperitoneum , strong alterations of the peritoneum became visible and parts of the unde rlying basal lamina were laid bare. Tumor cells attached to the free basal lamina and formed predominantly diffuse metastases throughout the peritoneu m within the next 96 hours. No diffuse changes of the peritoneal surface an d no diffuse metastases were observed in the second group. Singular metasta ses followed gravity and involved the anterior abdominal wall. CONCLUSIONS. Because these findings explain the clinical findings of intraa bdominal metastases after laparoscopy the authors conclude that the pneumop eritoneum provokes particular damage to the peritoneum that induces a speci fic intraperitoneal tumor growth. (C) 1999 American Cancer Society.