Cancer Information
- Colorectal cancer is the third most common cancer in both men and women and the third leading cause of cancer-related mortality in both men and women in the United States.
- It is estimated that approximately $8.4 billion is spent in the United States each year on treatment of colorectal cancer.
- Estimated new cases in 2008: 108,070
- Estimated deaths related to colorectal cancer in 2008: 49,960
What Is Colorectal Cancer?
Colorectal cancer is a disease in which malignant (cancer) cells form in the tissues of the colon or the rectum. In order to understand colon and rectal cancer, collectively known as colorectal cancer; it might first help to understand what parts of the body are affected and how they work.
Anatomy of the Colon:
The colon is a 6-foot long muscular tube connecting the small intestine to the rectum. The colon, which along with the rectum is called the large intestine, is a highly specialized organ that is responsible for processing waste so that emptying the bowels is easy and convenient. The colon removes water from the stool, and stores the solid stool. Once or twice a day it empties its contents into the rectum to begin the process of elimination. Cancer that forms in the tissues of the colon (the longest part of the large intestine) is called colon cancer.
Anatomy of the Rectum:
The rectum is an 8-inch chamber that connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let you know that there is stool to be evacuated, and to hold the stool until evacuation happens. Cancer that forms in the tissues of the rectum (the last several inches of the large intestine before the anus) is called rectum cancer.
Screening for Colorectal Cancer:
Finding and treating colorectal cancer early may prevent death from colorectal cancer. Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread. It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms.
Currently there are five different screenings that are commonly used to look for colorectal cancer:
Fecal occult blood test - is a test to check stool (solid waste) for blood that can only be seen with a microscope. Small samples of stool are placed on special cards and returned to the doctor or laboratory for testing. Blood in the stool may be a sign of polyps or cancer.- Sigmoidoscopy - is a procedure to look inside the rectum and lower part of the colon for polyps, and abnormal areas, or cancer. A sigmoidoscope is inserted through the rectum into the lower colon. A sigmoidoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer. A sigmoidoscopy and a digital rectal exam (DRE) may be used together to screen for colorectal cancer.
- Barium enema – is a series of x-rays of the lower gastrointestinal tract. A liquid that contains barium (a silver-white metallic compound) is put into the rectum. The barium coats the lower gastrointestinal tract and x-rays are taken. This procedure is also called a lower GI series.
Colonoscopy - is a procedure to look inside the rectum and colon for polyps, abnormal areas, or cancer. A colonoscope is inserted through the rectum into the colon. A colonoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove polyps or tissue samples, which are checked under a microscope for signs of cancer. - Digital rectal exam - is an exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower part of the rectum to feel for lumps or anything else that seems unusual.
Risk Factors for Colon Cancer
Avoiding risk factors and increasing protective factors may help prevent colorectal cancer. Most people with a certain risk factors for cancer do not actually get the disease. Doctors cannot always explain why one person gets cancer and another does not. Talk to your doctor or other health care professional about cancer prevention methods that might help you.
The following risk factors may increase the risk of colorectal cancer:
- Age - The risk of colorectal cancer begins to increase after age 40 and continues to increase as you get older.
- Obesity and lack of exercise - Obesity is linked to an increased risk of colorectal cancer. A lifestyle that does not include regular exercise may also be linked to an increased risk of colorectal cancer.
- Smoking - Smoking cigarettes is linked to an increased risk of developing colorectal adenomas (noncancerous tumors) and colorectal cancer. Cigarette smokers who have had surgery to remove colorectal adenomas have an increased risk for the adenomas to recur.
- Alcohol - Consuming alcoholic beverages may increase the risk of colorectal cancer.
Protective Factors for Colorectal Cancer
These following protective factors may decrease the risk of colorectal cancer:
- Hormone replacement therapy - Studies have shown that hormone replacement therapy (HRT) that includes both estrogen and progesterone lowers the risk of colorectal cancer in postmenopausal women. HRT with estrogen alone does not lower the risk. However, hormone use may increase the risk of breast cancer, heart disease, and blood clots.
Polyp removal - Most colorectal polyps are adenomas, which may develop into cancer. The removal of polyps in the colon and rectum may lower the risk of colorectal cancer. Bleeding and infection sometimes occur after polyps are removed during a colonoscopy or sigmoidoscopy.
