My friend is worried that he has intestinal cancer. What are the early symptoms of this disease?

Intestinal cancer is a malignant tumor, mainly due to long-term bad diet, family genetics and other factors. Usually patients in the early stage of the disease, mostly asymptomatic, only a few appear abdominal discomfort, dyspepsia, stool occult blood and other phenomena. Later, with the development of the disease, patients will appear stool habits change, abdominal pain, abdominal mass, fever and other symptoms.