Background: The association between intraoperative hemorrhage and the type of recurrence was examined, with a focus on peritoneal metastasis.
Methods: A total of 540 patients who underwent macroscopically curative gastrectomy for advanced gastric cancers were reviewed for various clinicopathological characteristics, such as the amount of intraoperative hemorrhage and the pattern of recurrence. Additionally, adhesion assays using gastric cancer cells and mesothelial cells were performed in the presence of blood plasma to assess its effects on cell adhesion.
Results: Large intraoperative hemorrhages were correlated with a higher risk of peritoneal metastasis, while small hemorrhages were not. However, there were no significant differences in the incidence of all recurrences or other types of recurrence between both groups. Multivariate analysis of all cases (T2-4) revealed that large intraoperative hemorrhages were not an independent risk factor for peritoneal recurrence (p = 0.144); however, the large hemorrhage group developed peritoneal recurrence more frequently than the small hemorrhage group in each T stage. In the adhesion assay, the ability of cancer cells and mesothelial cells to adhere to each other was enhanced by the addition of plasma to the culture medium. The addition of heparin significantly decreased the plasma-induced enhancement of cell adhesion of Kato III, but not MKN45 or MKN74.
Conclusions: Advanced gastric cancer patients accompanied by a large amount of intraoperative hemorrhage are more likely to develop peritoneal recurrence, and this risk might be due, at least in part, to the increased ability of cancer cells and mesothelial cells to adhere to each other.