Abstract

Objective: Tumor immunity infiltrate, density and location in the microenvironment could be predictive value for survival in patients with rectal cancer. The aims of this study is to evaluate tumor microenvironment using immune adaptive cells as CD3+ and CD8⁺ T lymphocytes and explore relationship between clinic pathological features, therapeutic response, survival outcomes and immunoscore.

Materials and Methods: Scoring system “immunoscore” in pretreated biopsies tissues from rectal cancer. Quantification of cytotoxic and memory T cells in the Core of Tumor (CT) and in the tumor’s Invasive Margin (IM)

Results: According to 5 immunoscore groups I0, I1, I2, I3 and I4, the frequency of each group was respectively 9.3%, 18.5%, 22.2%, 18.5% and 31.5%. When grouping immunoscore into 3 groups’ data allow to a proportion of 27.8% for low immunoscore, 22.2% for moderate immunoscore and 50% for high immunoscore. Furthermore, in two-tailed classification (I0, I1, I2 versus I3 and I4) 50% of tumors were ranged as low immunoscore versus 50% as high immunoscore.

Conclusion: High Lymphoid infiltration in CT and IM prove that tumor microenvironment could be a predictive factor, on pretreated biopsies, for tumor sensibility after neoadjuvant treatment in rectal cancer. This reflects the importance role of high immune infiltration in prediction of complete therapeutic effect. Immunoscore method should be considered as predictive marker for overall survival.

Keywords: Immunoscore, CD3, CD8, Therapeutic response, Rectal cancer, Neoadjuvant treatment, Morocco.