What are the symptoms before colorectal cancer?

As early as the middle of the 20th century, scientists discovered that the formation of cancer is a multi-step, multi-stage evolutionary process. This process begins with gene mutation or abnormal expression in molecular biology, leading to abnormal cell differentiation and growth, and finally forming a malignant tumor characterized by invasion and metastasis.

First, let us understand two medical concepts. One is precancerous disease, which refers to certain diseases that are prone to cancer and belong to the clinical category; the other is precancerous lesions, which refers to a group of pathological histological changes that are prone to cancer, namely dysplasia, currently also called intraepithelial neoplasia.

Current research suggests that precancerous diseases of intestinal cancer mainly include colorectal adenoma, inflammatory bowel disease and some familial hereditary syndromes. Precancerous lesions of intestinal cancer refer to dysplasia of the colorectal mucosa, which can occur on the basis of adenoma, or on the flat mucosa, ulcer margins or inflammatory polyps of inflammatory bowel disease and colonic schistosomiasis. Dysplasia is also called atypical hyperplasia. Dysplasia of intestinal mucosa refers to the significant cell differentiation and structural abnormalities of the intestinal enamel membrane and a high tendency to cancer, that is, abnormal glandular duct structure and abnormal cell morphology. The degree of dysplasia refers to the degree of deviation from normal in cell morphology and tissue structure. Dysplasia is generally divided into three levels: mild, moderate and severe at home and abroad. It is now believed that dysplasia is a clear tumor growth, representing the initial stage of tumor growth and belonging to the pre-invasive stage of cancer.

Studies have reported that intramucosal carcinoma and invasive carcinoma almost all occur in adenomas with moderate or severe atypical hyperplasia. The risk of severe atypical hyperplasia is closely related to age, adenoma histopathological type and tumor size. Early detection and early treatment are the key to the prevention and treatment of colorectal cancer, and those with colorectal precancerous diseases and precancerous lesions are high-risk groups that need to be followed up. With the in-depth study of colorectal precancerous diseases and precancerous lesions, it is expected that the development of colorectal cancer can be blocked early and ideal clinical treatment effects can be achieved.