Neutrophil infiltration in peritoneal metastasis affects prognosis in patients with ovarian cancer.

The impact on prognosis of neutrophil infiltration in the microenvironment of ovarian cancer remains to be elucidated. In this study, we analyzed the association between neutrophil infiltration in peritoneal metastasis and prognosis. Furthermore, we analyzed the correlation between neutrophil infiltration in peritoneal metastasis and the number of peripheral blood neutrophils, the degree of neutropenia, vascular endothelial area, and the number of stromal cells. Thirty-four specimens each of primary and metastatic advanced ovarian cancer with high-grade serous carcinoma histology were taken. Staining for MPO, CD31, and αSMA was performed on all specimens. We investigated the correlation among tissue neutrophil infiltration, prognosis, and neutrophil indicators from blood tests. Survival analysis showed that neutrophil infiltration in the primary tumor had no impact on prognosis, whereas high neutrophil infiltration in the disseminated tumor significantly shortened progression-free survival and overall survival. No correlation was found between neutrophil infiltration and the number of peripheral blood neutrophils, the degree of neutropenia, area of vascular endothelial cells, and number of stromal cells. Neutrophil infiltration into disseminated lesions of the omentum has a significant impact on prognosis. The results of the present study may provide insights for refining clinical approaches.