gastrointestinal disorders
Colorectal Cancer
Etiology of Colorectal Cancer
Colorectal cancer (CRC) most often occurs as transformation within Polyps of the Colon and Rectum . About 80% of cases are sporadic, and 20% have an inheritable component. Many genetic syndromes predispose to CRC: Familial Adenomatous Polyposis None Lynch Syndrome None Peutz-Jeghers Syndrome None Juvenile polyposis syndrome MUTYH Polyposis Syndrome None Predisposing medical conditions include chronic inflammatory disorders (eg, Ulcerative Colitis , Patients in populations with a high incidence of CRC eat low-fiber diets that are high in animal protein, fat, and refined carbohydrates. Carcinogens may be ingested in the diet but are more likely produced by bacterial action on dietary substances or biliary or intestinal secretions. The exact mechanism is unknown. CRC spreads by direct extension through the bowel wall, hematogenous metastasis, regional lymph node metastasis, and perineural spread. 