Colon or colorectal cancer is one of the most common cancers and is the second leading cause of cancer death in France. Here are the signs that should prompt you to consult a specialist. Transit disorders A malignant tumor of the inner lining of the colon or rectum, colon cancer is most often manifested by intestinal transit disorders, such as sudden and brutal constipation, or prolonged diarrhoea. Persistent abdominal discomfort This cancer can also lead to abdominal discomfort. Among them, bloating, cramps, and pain in the abdomen that can persist for several weeks. Blood in the stool Another sign that should alert you: the presence of blood in the stool. Indeed, colorectal polyps can cause small bleeding through the rectum. Knowing that these can be difficult to detect with the naked eye. Unexplained weight loss Finally, you should know that colon cancer tends to reduce appetite and cause weight loss. In case of rapid and involuntary weight loss, it is best to consult a gastroenterologist.