Cancer is when cells in the body change and grow out of control. Typically,
your body grows cells as they are needed, and they die when your body no longer needs them. Colorectal cancer is
cancer that starts in either your colon or your rectum. In most cases, this type cancer does not start in both the
colon and the rectum. However both types of cancer have many features in common, so they are often called colorectal
cancer. Excluding skin cancers, colorectal cancer is the third most common cancer in both men and women in the United
States and the second leading cause of cancer-related deaths overall, according to the American Cancer Society.
Types of Colorectal Cancer
Here is an overview of the types of cancer that can start in the colon and rectum:
The most common type of colorectal cancer. More than 95% of colorectal cancers are adenocarcinoma.
This cancer starts in the lining of internal organs. The tumors start in gland cells that release, or secrete, fluids.
Gastrointestinal Stromal Tumor (GIST):
These tumors start in special cells in the wall of the digestive tract. They may be found anywhere in the digestive
tract, but they rarely appear in the colon. They may be benign, or not cancer, at first, but many do turn into cancer.
This cancer starts in a type of immune cell called a lymphocyte. Lymphomas often start in bean-sized groups of lymphocytes,
called lymph nodes. But they can also start in the colon, rectum, or other organs.
This cancer starts in special hormone-making cells in the intestine.
These tumors start in blood vessels, muscle, or connective tissue in the colon and rectum wall.
How does Colorectal Cancer Spread?
Most colorectal cancer starts as a growth, or polyp, on the inner lining of the colon or rectum. Over time, some types of polyps can
become cancer. Over time, the cancer can grow beyond the colon or rectum and into nearby organs or lymph nodes. The cancer cells can
also travel to other parts of the body where they can form new tumors. This is known as metastasis.