Tips for Health

Screening for Colorectal Cancer

By on March 11, 2012 in Diseases, Health, Prevention with 0 Comments

Key Points

  • Colorectal cancer is a disease in which cells of the colon or rectum become abnormal, divide without control and form a mass, called a tumor.
  • No one knows the exact causes of colorectal cancer. However, studies show that certain factors increase the chances that a person will develop colorectal cancer.
  • Health care providers may suggest one or more tests as screening for colorectal cancer. Analysis of fecal occult blood test (FOBT), sigmoidoscopy, regular colonoscopy, virtual colonoscopy, barium enema double contrast or digital rectal exam, they are all tests of this type .
  • People should talk with healthcare provider about when to begin having screening for colorectal cancer, what type of tests performed and the benefits and risks of each, and the frequency with which they must make appointments.
  • Are being studied new methods of screening for colorectal cancer, and genetic analyzes of stool samples.

What is colorectal cancer?

Colorectal cancer is a disease in which cells of the colon or rectum become abnormal and divide without control, creating a mass that is what is called tumor. (The colon and rectum are parts of the digestive system to extract nutrients from food and water and stores solid waste until it passes out of the body).

It is possible that colorectal cancer cells also invade and destroy the tissue around them. They can detach from the tumor and spread to form new tumors in other parts of the body.

Apart from skin cancer, colorectal cancer is the third most common types of cancer in men (after prostate and lung) and women (after breast and lung). It is the second leading cause of cancer deaths in the United States after lung cancer. Although the rate of new cases and deaths resulting from this disease is declining in this country each year for the past 5 years, more than 145 000 new cases were diagnosed and more than 49,000 people died from colorectal cancer.

Who is at risk for colorectal cancer?

We don’t know what causes colorectal cancer. Certain factors that are linked to an increased chance of developing colorectal cancer are as follows:

  • Age -It is more likely that colorectal cancer occurs as people get older. Although this disease can occur at any age, most people with colorectal cancer are older than 50 years.
  • Polyps -Polyps are growths that protrude from the inner wall of the colon or rectum. They are relatively common in people over 50 years of age. Most polyps are benign (noncancerous), but experts believe that most colorectal cancers occurring in certain polyps are called adenomas.Therefore, the detection and removal of these tumors may help prevent colorectal cancer. The procedure to remove polyps is called polypectomy.Some people may be genetically predisposed to have polyps. Familial adenomatous polyposis is a rare, inherited condition in which hundreds of polyps present in the colon and rectum. Since people with this condition are extremely likely to develop colorectal cancer, are often treated with surgery to remove the colon and rectum called a colectomy. The rectum sparing surgery may be an option. Also, the Food and Drug Administration (Food and Drug Administration, FDA) has approved an anti-inflammatory drug, celecoxib, for the treatment of familial adenomatous polyposis. Doctors may prescribe this drug in combination with monitoring and surgery to control this condition.
  • Personal History -The person who has already had colorectal cancer have an increased risk of colorectal cancer a second time. In addition, research studies show that some women with a history of ovarian cancer, uterine or breast cancer have a higher than average chance of developing colorectal cancer.
  • Family history -Close relatives (parents, siblings or children) of a person who has had colorectal cancer are more likely to have this type of cancer themselves, especially if the relative had cancer at a young age. If several family members have had colorectal cancer, the chances increase even more.
  • Ulcerative colitis or Crohn’s disease , ulcerative colitis is a condition that causes inflammation and sores (ulcers) in the lining of the colon. Crohn’s disease (also called Crohn’s colitis) causes chronic inflammation of the gastrointestinal tract, most commonly the small intestine (the part of the digestive tract that lies between the stomach and intestine). People with ulcerative colitis or Crohn’s disease may be more likely to develop colorectal cancer than those without these conditions.
  • Diet -Some evidence suggests that the formation of colorectal cancer may be related to the consumption of a diet rich in red and processed meat and low in consumption of grains, fruits and vegetables. Researchers are exploring the role of these and other dietary components in the evolution of colorectal cancer.
  • Exercise -Some evidence suggests that a sedentary lifestyle may be associated with an increased risk of developing colorectal cancer. By contrast, people who exercise regularly may have a lower risk of colorectal cancer. 
  • Cigarette -Epidemiological studies show growing evidence suggesting that cigarette smoking, especially for a long time increases the risk of colorectal cancer.What are the screening tests and why are they important?

    The screening tests are tests to identify health problems before they cause symptoms. Screening for colorectal cancer can detect cancer, polyps, polypoid lesions, which have flat or slightly sunken abnormal cell growth, and other conditions. The polypoid lesions occur less frequently than polyps, but may also result in colorectal cancer.

    If the tests detect problems, diagnosis and treatment can be done promptly. Also, finding and removing polyps or abnormal cell growth in other area can be one of the most effective ways to prevent the formation of colorectal cancer. Also, colorectal cancer, in general, is more treatable when found early and before it has had a chance to spread.

    What methods are used as screening for colorectal cancer?

    Health care providers may suggest one or more of the following tests as screening for colorectal cancer:

    • The analysis of FOBT (fecal occult blood test, FOBT): This test detects blood in the stool (feces). Currently, there are  two types of FOBT. The first type, called stool guaiac test in which a chemical used to detect the presence of hemoglobin in stool. The heme portion of the protein part of the blood hemoglobin and contains iron. The other type of FOBT is called fecal immunochemical test, which uses antibodies to detect human hemoglobin protein in the fecesStudies have shown that this test may help reduce the number of deaths from colorectal cancer 15 to 33 percent when performed every year or every two years in people aged between 50 and 80 years.
    • Sigmoidoscopy : During this test, we examine the rectum and lower colon using a lighted instrument called a sigmoidoscope. Sigmoidoscopy can find precancerous or cancerous tumors in the rectum and lower colon which may be extracted or a biopsy can be performed. Studies suggest that carrying out regular examination in screening with sigmoidoscopy after he age of 50 can reduce the number of deaths from colorectal cancerThorough cleansing of the lower colon is necessary for this test.
    • Colonoscopy : During this test, the rectum and the entire colon is examined using a lighted instrument called a colonoscope. Colonoscopy can find precancerous or cancerous growths throughout the colon, even in the top of the colon, which could be missed by sigmoidoscopy. These tumors can be removed or biopsied. However, it is unclear whether colonoscopy can reduce the number of deaths from colorectal cancer. Thorough cleansing of the colon is necessary for this test and almost all patients receive some form of sedative.
    • Virtual colonoscopy (also called CT colonography): During this test, using a special x-ray equipment to produce pictures of the colon and rectum. A computer organizes these photos and create detailed images that can show polyps and other abnormalities. Since this test is less invasive than standard colonoscopy and does not require sedation, virtual colonoscopy may be more comfortable and faster. As with standard colonoscopy, you need a thorough cleansing of the colon before the test. Not yet known whether virtual colonoscopy can reduce the number of deaths from colorectal cancer.
    • Barium enema double contrast : This test consists of a series of radiographs of the entire colon and rectum. The films are taken after giving the person an enema with a barium solution and pumping air into the colon. The barium and air help to outline the colon and rectum on the x-rays. Research has shown that the barium enema double contrast may miss small polyps. It can only detect about 30 to 50 percent of cancers that can be found with a normal colonoscopy.
    • The digital rectal exam (digital rectal exam, DRE): In this test, the health care provider inserts a gloved and lubricated finger into the rectum to check for abnormal areas. The DRE can examine only the lower rectum. It is often included in routine physical examinations.

    Scientists continue to study the methods for screening for colorectal cancer, both individually and in combination, to determine their effectiveness. There are also ongoing studies to clarify the risks and prejudices of each test. See Question 5 where you see a table outlining some of the advantages and disadvantages, including potential harm of the screening of colorectal cancer.

    How can people and their health care providers decide which screening for colorectal cancer using and how often?

    Several large organizations such as the Brigade of the U.S. Preventive Services. States. (U.S. Preventive Services Task Force) (group of experts convened by the Public Health Service of the U.S.. States.), The American Cancer Society and professional associations, have established guidelines for screening for colorectal cancer. Although some details of their recommendations vary with regard to screening to be used and frequency of testing, all of these organizations support screening for colorectal cancer.

    It advises people to consult their health care provider about when will be start screening for colorectal cancer, what tests should be made, the benefits and risks of each test and the frequency with which appointments must be made .

    The decision to have a certain test will take into account several factors, including:

    • Sage, medical history, family history and general health;
    • Accuracy of the examinations;
    • Any damage of the review;
    • Preparation required for the review;
    • Required sedation during the examination;
    • Follow-up care after the test;
    • Convenience of the review;
    • Cost of the test and if covered by insurance.

    Do insurance companies pay for screening for colorectal cancer?

    Insurance coverage varies. It should be verified with the insurance company to determine benefits with respect to screening for colorectal cancer. Because virtual colonoscopy is a fairly new procedure, you may find refund policies are less clear than those of other tests. Medicare covers a number of screening for colorectal cancer to their heirs. Specific information about Medicare benefits is available on the Medicare website

    What happens if a selective review of colorectal cancer screening shows an abnormality ?

    If a screening finds any problems, the health care provider will perform a physical examination and medical history of the person and his family are checked. Further tests may also be ordered. These may include x-rays of the gastrointestinal tract, sigmoidoscopy or, more often, colonoscopyThe health care provider may also order a blood test called a CEA assay to measure carcinoembryonic antigen, a protein that is found sometimes in greater amounts in patients with colorectal cancer. If an abnormality is found during a sigmoidoscopy, a colonoscopy can be recommended. If an abnormality is found during a standard colonoscopy, a biopsy or polypectomy could be done to determine whether cancer is present. If an abnormality is found during a virtual colonoscopy, patients will be recommended to get a regular colonoscopy the same day.


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