Influence of peritoneal factors on port-site metastases in a xenograft ovarian cancer model

Objective We determine the main physical effects of pneumoperitoneum on tum our dissemination and port-site metastases occurrence. Design A prospective randomised study in rats. Methods A human ovarian cancer cell line (IGR-OV1) was xenografted in nude rats. Seven days after cancer inoculation, surgery was performed. Rats were randomised in two main groups and underwent either: gasless laparoscopy (n = 20) CO2 laparoscopy with pneumoperitoneum pressure at 4 mmHg (n = 20), o r 8 mmHg (n = 20) with in each case, increasing operative duration: 30,60,9 0 or 120 minutes (five rats for each time). Animals were killed seven days after the intervention. Main outcome measures Tumour dissemination and frequency of port-site metas tases. Results Tumour dissemination was not influenced by gas pressures or duratio n of procedure. The rate of rats with at least one port-site metastasis (on e or two) was similar in all groups: gasless: n = 10/20; 4 mmHg CO2: 5/20; 8 mmHg CO2: 7/20,(P = 0.26). The number of port-site metastases were signif icantly higher in the,gasless group compared with the 4 mmHg CO2 group (15/ 40 (37.5%) vs 5/40 (12.5%), P = 0.01). Difference was not significant betwe en the 8mmHg group and the gasless group (9/40(22.5%) vs 15/40(37.5%), P 0. 14) or the 4mmHg group (9/40(37.5%) vs 5/40 (12.5%), P = 0.24). Duration of procedures had no significant influence on port-site metastases rate (P > 0.05). Conclusions Unlike previous animal studies, port-site metastases were more frequent with gasless laparoscopy than with CO2 pneumoperitoneum. Local per itoneal factors could play an important role in port-site metastases mechan ism.