Abstract: OBJECTIVE: To detect changes of inflammatory factors in intraepithelial colorectal adenomas，and to investigate correlations between the factors and gradings of the adenomas. METHODS: Clinical data from 200 cases of patients with adenomas were retrospectively analyzed. The adenomas were divided into different groups according to their neoplasia grades. Age，sex，adenoma location，number of adenomas，maximum adenoma diameter，counts of neutrophils，platelets，monocytes and lymphocytes，mean platelet volumes，ratios of platelets to lymphocytes (PLR)，neutrophils to lymphocytes (NLR) and monocytes to lymphocytes (MLR)，systemic Immune-inflammation indices (SII)， and carcinoembryonic antigens (CEA) were analyzed. RESULTS: The AUC of PLR，NLR，SII，MLR were 0.614，0.653，0.656 and 0.593，respectively. The optimal cut-off values of PLR，NLR，SII，MLR were 165.01，1.87，465.71 and 0.26，respectively. Univariate analyses showed that PLR，NLR，SII，MLR，CEA，neutrophil count、lymphocyte count，adenoma location，maximum adenoma diameter were significantly related to the neoplasia grades of the adenomas. According to the binary Logistic regression analyses，PLR，SII and maximum adenoma diameters were the risk factors for high-grade intraepithelial neoplasia. CONCLUSION: The higher the platelet-to-lymphocyte ratios and systemic inflammatory response indices in the peripheral blood of patients with colorectal adenomas，the greater the likelihood of high-grade intraepithelial neoplasia. Their positive correlations may be useful for enhancing therapy for colorectal adenoma.

Key words: colorectal adenoma, inflammatory markers, ratio of platelet to lymphocyte, systemic immune-inflammation index, intraepithelial neoplasia