Suppressive effect of bevacizumab on peritoneal dissemination from gastric cancer in a peritoneal metastasis model

Vascular endothelial growth factor (VEGF) has been reported to enhance vascular permeability and angiogenesis in the abdominal wall, thereby contributing to peritoneal dissemination with malignant ascites. We conducted this experimental study to find out if bevacizumab, a humanized monoclonal antibody against VEGF, had a suppressive effect on peritoneal dissemination from gastric cancer, in an experimental nude mouse model of peritoneal metastasis. Each mouse was treated with a single intraperitoneal (i.p.) injection of bevacizumab. Five mice were killed, and we measured their body weight, the mean number of tumor nodules, and the volume of ascites. We also extracted retroperitoneal tissues for histological examination, to count the frequency of mitosis, and to calculate the mitotic index. Another five mice were monitored until death, and their mean survival duration was calculated. The volume of ascites and the mitotic index were significantly lower in the therapy group than in the nontherapy group (P = 0.042 and P < 0.01, respectively). The survival curve of the therapy group was significantly higher than that of the nontherapy group (P = 0.005). Bevacizumab may suppress peritoneal dissemination from gastric cancer.