Diagnostic value of inflammatory cell infiltrates, tumor stroma percentage and disease-free survival in patients with colorectal cancer

The anticancer immune defense mechanism involves humoral and cellular responses. The main effector mechanisms of antitumor responses involve the following: the activity of cytotoxic T cells; the activation of macrophages and neutrophils; the activity of cytokines secreted by T cells; and natural killer cell activity. Selected cell populations are responsible for the stimulation or suppression of the immune system against tumor cells. Therefore, the aim of the present study was to evaluate the location, extent and composition of the cellular inflammatory infiltration of tumors in patients with colorectal cancer (CRC). In addition, the correlation between cellular inflammatory infiltration, and anatomoclinical and histopathological features of patients was evaluated. The study involved 160 patients diagnosed with primary operable CRC. The local inflammatory infiltrate was assessed in the invasive front and center of the tumor using light microscopy with hematoxylin and eosin (H&E) staining, according to the Klintrup-Makinen criteria, tumor stroma percentage, and Glasgow microenvironment score. The inflammatory infiltrate in the invasive front of the tumor was correlated with gender (P=0.018), the invasion of blood vessels (P=0.020) and lymph vessels (P=0.038), the presence of tumor-infiltrating lymphocytes in the invasive front (P=0.033) and center (P<0.001) of the tumor, fibrosis (P<0.001), and the degree of desmoplasmic stroma (P=0.004). In contrast, inflammatory infiltration in the center of the tumor was associated with the tumor node metastasis stage (P=0.012), Dukes' stage (P=0.009), primary tumor stage (P=0.036), lymph node status (P=0.005), number of lymph nodes (P=0.006), invasion of lymph node pouches (P=0.021), size of lymph node metastasis (P=0.025) and the degree of desmoplasmic stroma (P=0.002). The low-group, who demonstrated an absent or weak inflammatory cell infiltrate in the invasive front of the tumor, had a statistically significant shorter disease-free survival (DFS) time (P=0.004). Inflammatory cell infiltrate in the invasive front was identified as an independent predictive factor in CRC (P=0.041). In conclusion, the degree of inflammatory cell infiltration in the invasive front of the primary tumor significantly affects various variables that determine disease progression and DFS rates of patients with CRC. Furthermore, the routine histopathological assessment of this parameter in tissue stained with H&E may have potential prognostic value.