This National Cancer Institute (NCI) booklet (NIH Publication No. 06-1552) is about cancer of the colon and rectum. Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer that starts in either of these organs may also be called colorectal cancer.

In the United States, colorectal cancer is the fourth most common cancer in men, after skin, prostate, and lung cancer. It is also the fourth most common cancer in women, after skin, breast, and lung cancer.

You will read about possible risk factors, screening, symptoms, diagnosis, and treatment. You will also find lists of questions to ask your doctor. It may help to take this booklet with you to your next appointment.

Important terms appear in italics. By clicking on the term, you can get its definition. Most words have a "sounds-like" spelling to show how to pronounce them. Definitions of more than 4,000 terms are also on the NCI Web site in the NCI Dictionary of Cancer Terms. You can access it at http://www.cancer.gov/dictionary.

If you want more information about colorectal cancer, please visit our Web site at http://www.cancer.gov/cancertopics/types/colon-and-rectal. Or contact our Cancer Information Service. We can answer your questions about cancer. We can send you NCI booklets, fact sheets, and other materials. You can call 1-800-4-CANCER (1-800-422-6237) or instant message us through the LiveHelp ¹ service at http://www.cancer.gov/help.

Glossary Terms

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

Having to do with the colon or the rectum.