Colon cancer refers to cancer of the large intestine (colon) while rectal cancer refers to cancer of the last 6 inches of the colon (rectum). Cancers affecting either of these organs are collectively known as colorectal cancer. Colorectal cancer is the third most common cancer in men around the world, and fourth most common for women.
Colorectal cancer occurs when some of the cells that line the colon or the rectum become abnormal and grow uncontrollably. Most cases of colorectal cancer begin as small, benign clumps of cells called polyps. Over time some of these polyps may become cancerous. Polyps may be small and produce few, if any, symptoms.
Regular screening tests can help prevent colon cancer by identifying polyps before they become cancerous. If signs and symptoms of colon cancer do appear, they may include changes in bowel habits, blood in your stool, abdominal pain, bloating, and fatigue.