Osmotic lysis of tumor spill in ovarian cancer: A murine model

OBJECTIVE: Our purpose was to determine, in the murine model, whether human ovarian cancer cells injected intraperitoneally are subject to osmotic lysis by peritoneal lavage with sterile water, thereby decreasing the establishment of peritoneal implants. STUDY DESIGN: Preliminary experiments on six nude mice determined that the injection of 20 million cells of the SKOV-3 cell line reliably leads to the establishment of intraperitoneal tumor xenografts in the mice within 60 days. Four other nude mice functioned as sham controls undergoing peritoneal lavage with 3 to 4 ml of saline solution or sterile water to determine any adverse effects from the lavage alone. Subsequently, 36 nude (nu/nu) mice were injected intraperitoneally with 1 ml of the SKOV-3 cell line at a concentration of 20 million cells per milliliter. Alternate mice then underwent intraperitoneal lavage with either 3 to 4 ml of normal saline solution (control group) or sterile water (study group). The mice were followed up until tumor growth caused a moribund status or until 60 days after injection and then were killed. At necropsy the number and size of tumor nodules were recorded, and each mouse was assigned a composite tumor score. Statistical comparison used the χ² or Fisher's exact test for discrete variables. Time to failure analysis used the Kaplan-Meier method. RESULTS: Tumor growth occurred in 35 of 36 (97%) of the mice during the study period. In the first 30 days 89% of the saline solution group grew clinically visible tumor compared with 55% of the water group (p = 0.03). Ascites developed more frequently in the water group than in the saline solution group. The median tumor scores at death were significantly higher for the water group versus the saline solution group. Survival time, as determined by the time from injection until moribund status, was worse for the water group (p = 0.002). CONCLUSIONS: Intraperitoneal lavage with sterile water did not offer protection against the establishment of xenografts after the intraperitoneal injection of human ovarian cancer cells in the nude mouse model. (Am J Obstet Gynecol 1996;175:1489-92.)