The Effects Of Single Large Dose Of Intracavitary Irradiation On Tumor Blood Vessels And Tumor-infiltrating Immune Cells In Cervical Cancer Patients

Purpose: To investigate the changes of tumor blood vessel density,vascular function and the immune microenvironment one week after brachytherapy in single dose of 5-6 Gy.Methods: Twenty-three patients with cervical cancer were received brachytherapy in single dose of 5 Gy.The tumor tissue biopsies before and at one week after brachytherapy were collected and the expression of CD31 and NG2 in tumor tissue was analyzed by immunohistochemistry.The composition of tumor-infiltrating immune cell populations and the expression of CD279(PD-1)and CD274(PDL-1)were determined by flow cytometry.Results: The expression of CD31(P<0.01)and NG2(P<0.05)was increased in cervical cancer tissues one week after brachytherapy,compared with those of before treatment.These data suggest that brachytherapy increases tumor vessel density and improves vascular function.The proportions of CD4+TILs and CD8+TILs showed individual differences after brachytherapy.The levels of CD279(PD-1)were slightly decreased in total cells,CD4+ cells and CD8+ cells.The expression of CD274(PD-L1)increased in lymphocytes while their overall expression levels in the total viable cells showed a trend to decrease.Although the percentage of tumor-associated macrophages(TAM)in the total viable cells was increased,the proportion of M2-TAM was decreased.These data indicate that the immunosuppressive components within the tumor microenvironment are reduced after brachytherapy.Conclusions: Tumor vascular function and immune status in the tumor microenvironment are improved one week after brachytherapy in single dose of 5-6 Gy.