Colon cancer is cancer that develops in the colon or large intestine from polyps that are usually benign or non-cancerous. However, over time the polyps can mutate into a malignant tumor, which is a growth of tissues made up of cancerous cells. In the United States, colon cancer is the fourth most common cancer among men and women of all races, according to MedlinePlus. If colon cancer originates within the last six inches of the colon, it is called rectal cancer.
Bleeding from the Tumor
Bleeding doesn't occur until late in the course of the cancer. Blood can be seen on the toilet paper, on the outside of the stool, or upon wiping the anus. The bleeding is evident when bright red blood typically coats the stool, which causes the feces to turn very dark. In most cases, the bleeding is usually mild, but if the bleeding is regular, the body can lose enough RBCs to cause anemia, according to Patient UK.
A Change in Bowel Habits
A change in bowel habits may be a worrying sign of colon cancer, especially if an unexplained change persists for a week or more, and it is accompanied by persistent abdominal pain. Variable and erratic bowel habits alternate between constipation and diarrhea. If the cancer blocks the passage of stool, it causes constipation. Constipation can cause symptoms, such as pain, bloating and flatulence. Diarrhea means a change in the appearance of stool, including stools that are loose and watery.
Abdominal Pain
The symptoms gradually become severe as the tumor grows and spreads to a different part of the body from where it started. In the advanced stages, people with colon cancer more often experience unexplained weight loss and feel fatigue all the time. Blockages in the bowel caused by colon cancer can lead to cramping pain in the abdomen, accompanied by bloating and loss of appetite or anorexia.
