Immune Quantitative Analysis And Impact Of Immunoscore On Prognosis Of Peritoneal Metastasis Of Colorectal Cancer

Background: Peritoneal metastasis originating from primary colorectal cancer(p CRC)is a common advanced disease.Immunoscore has been established to predict the prognosis of patients with stage I-III colorectal cancer.However,the feasibility of immunoscore to predict the prognosis of colorectal cancer peritoneal metastases(CRCPM)has not been reported.We quantitatively analyzed the immune status of CRCPM,and explored the prognostic value of different immune scoring systems of patients with peritoneal metastasis.Material and Methods: Peritoneal metastasis and ovarian metastasis in 68 patients with CRCPM were analyzed.The infiltration density of T cells,B cells,macrophages in the tumor center of peritoneal metastasis tumor center was analyzed by immunohistochemistry.The traditional immunoscore is established according to the infiltrating density of CD3+ and CD8+ T cells,and the TBM score was established by the infiltration density of CD3+,CD8+,CD20+,CD163+ cells.The prognostic value of IS and TBM scores were analyzed to predict relapse free survival(RFS)and overall survival(OS)via Kaplan Meier curve and Cox proportional risk model.T-test was used to analyze the the difference of infiltration density of immune cells of different subtypes in primary tumor tissue,peritoneal metastasis tissue and ovarian metastasis tissue.Results: CRCPM patients with high IS score(>1),high TBM1 score(≥2)or high TBM2 score(≥2)had significantly longer OS(IS: median OS,not reached vs 23 months,P=0.0078;TBM1: not reached vs 21.5 months,P=0.013;TBM2: 39.3 months vs 15.2 months,P=0.001),and patients with high IS score had a trend of improving RFS(13.4 months vs 11.0 months,P=0.067),however,high TBM1 score system and high TBM2 score system had no prognostic value predicting RFS.In the multivariate analysis,the three scoring systems still showed high value predicting OS,but there was no statistical difference predicting RFS.The infiltration density of CD8+T cells and CD20+B cells in peritoneal metastasis were significantly lower than that in primary colorectal cancer(P=0.0061;P=0.0036).The infiltration density of CD3+T cells,CD8+T cells,CD20+B cells and CD68+M cells in peritoneal metastasis tissue and ovarian metastasis tissue was significantly lower than that in all primary tumor tissues(peritoneal metastasis: CD3,P=0.0004;CD8,P=0.01;CD20,P<0.0001;CD68,P=0.0015;ovarian metastasis: CD3,P=0.0001;CD8,P=0.0117;CD20,P=0.011;CD68,P=0.0245;),CD163+ macrophage did not show decreased infiltration density.Conclusion: The IS and TBM scores system of peritoneal metastases is of great value to predict OS for patients with CRCPM after cytoreductive surgery.After peritoneal metastasis of colorectal cancer,the infiltration density of T and B cells in the metastases is significantly reducing.