Understanding Colorectal Cancer
Together, cancers of the colon and rectum are among the most common cancers in the United States. They occur in both men and women and are most often found among people who are over the age of 50. Colorectal cancer arises in the colon or rectum and occurs when cells in the colon or rectum become abnormal and divide without control or order. Cancer cells can invade and destroy the tissue around them. They can also break away from the tumor and spread to form new tumors in other parts of the body.
The exact causes of colorectal cancer are not known. However, studies show that certain factors increase a person’s chance of developing colorectal cancer:
Age - Colorectal cancer is more likely to occur as people get older. Most people who develop colorectal cancer are over the age of 50. However, the disease can occur at any age.
Diet - The development of colorectal cancer seems to be associated with a diet that is high in fat and calories and low in foods with fiber, such as whole grains, fruits, and vegetables.
Polyps - Polyps are benign growths (not cancer) on the inner wall of the colon or rectum. They are relatively common in people over age 50. Because most colorectal cancers develop in polyps, detecting and removing these growths may be a way to prevent colorectal cancer. Familial polyposis is a rare, inherited condition in which hundreds of polyps develop in the colon and rectum. Unless this condition is treated, a person who has it is extremely likely to develop colorectal cancer.
Personal history - A person who has already had colorectal cancer may develop colorectal cancer a second time. Also, research studies show that women with a history of ovarian, uterine, or breast cancer have a somewhat increased chance of developing colorectal cancer.
Family history - Close relatives (parents, siblings, or children) of a person who has had colorectal cancer are somewhat more likely to develop this type of cancer themselves, especially if the relative developed the cancer at a young age. If many family members have had colorectal cancer, the chances increase even more.
Ulcerative colitis - Ulcerative colitis is a condition in which the lining of the colon becomes inflamed. People who have ulcerative colitis are more likely to develop colorectal cancer.
What are the symptoms of colorectal cancer?
Common symptoms of colorectal cancer include a change in bowel habits, diarrhea, constipation, or feeling that the bowel does not empty completely; blood in the stool (either bright red or very dark in color); stools that are narrower than usual; general abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps); weight loss with no known reason; constant tiredness; and vomiting.
These symptoms can be caused by cancer or by a number of other conditions. It is important to check with a doctor if you are experiencing any of these complaints.
How do you screen for colorectal cancer?
People who have any symptoms or risk factors for colorectal cancer should ask their doctor when to begin screening for colorectal cancer, what tests to have, and how often to schedule appointments. Doctors may suggest one or more of the tests listed below as a part of regular checkups.
- A fecal occult blood test (FOBT) is a test for hidden blood in the stool. This test has been proven to reduce the death rate of colorectal cancer.
- A sigmoidoscopy is an examination of the rectum and lower colon with a lighted instrument.
- A colonoscopy is an examination of the rectum and entire colon with a lighted instrument.
- A double contrast barium enema is a series of x-rays of the colon and rectum. The x-rays are taken after the patient is given an enema with a white, chalky solution that contains barium to outline the colon and rectum
on the x-rays.
- A digital rectal exam (DRE) is a test in which the doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas.
How is colorectal cancer diagnosed?
To find the cause of symptoms, the doctor evaluates one’s personal and family medical history. The doctor also performs a physical exam and may order one or more diagnostic tests. These may include a blood test called a CEA assay to measure a protein called carcinoembryonic antigen that is sometimes higher in patients with colorectal cancer. A biopsy, the removal of tissue for examination under a microscope by a pathologist, may be done to determine if a person has cancer. The doctor may also order a
sigmoidoscopy, colonoscopy, or x-rays of the gastrointestinal tract.
If the diagnosis is cancer, the doctor will learn the stage (or extent) of disease. Staging is a careful attempt to find out whether the cancer has spread and, if so, to what parts of the body. Knowing the stage of the disease helps the doctor plan treatment. Additional tests may be performed to help determine the stage.
How is colorectal cancer treated?
Treatment for colorectal cancer depends on a number of factors, including the general health of the patient and the size, location, and extent of the tumor. Many different treatments and combinations of treatments are used to treat colorectal cancer.
Date last updated: January 6, 2003
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