What methods are used to screen for colorectal cancer ?
(1) FOBT - Fecal occult blood test
This test checks for hidden blood in fecal material (stool). It is done Once every year.
Disadvantages - This test fails to detect most polyps and some cancers. False-positive result.
(2) Flexible Sigmoidoscopy
The rectum and lower colon are examined using a lighted instrument called a sigmoidoscope. Precancerous and cancerous growths in the rectum and lower colon can be found and either removed or biopsied. Regular screening with sigmoidoscopy after age 50 can help reduce the death from colorectal cancer. It is done Once every 4 years.
Disadvantages - Any polyps in the upper part of the colon will be missed. There is a small risk of bleeding or tearing/perforation of the lining of the colon.
(3) Colonoscopy
The rectum and entire colon are examined using a lighted instrument called colonoscope.Precancerous and cancerous growths throughout the colon can be found and either removed or biopsied. It is done Once every 2 years.
Disadvantages - Small polyps, nonpolypoid lesions and cancers may not be detected but it is one the most sensitive tests currently available.
(4) Virtual Colonoscopy
Special x-ray equipment is used to produce pictures of the colon and the rectum that can show polyps and other abnormalities. It is done Once every 2 years.
Disadvantages - Small polyps, nonpolypoid lesions and cancers may not be detected.
(5) DCBE - Double contrast barium Enema
A series of x-rays of the entire colon and rectum are taken. DCBE may miss small polyps. It detects about 30 to 50 % of cancers. It is done Once every 2 years.
Disadvantages - Small polyps and cancer may not be detected. False-positive results are possible. During the test, biopsy cannot be performed. Polyps cannot be removed.
(6) DRE - Digital rectal exam
DRE allows examination of only the lower part of the rectum as a routine physical examination.
Disadvantages - Abnormalities only in the lower part of the rectum can be detected.
(7) Stool DNA Test
This test checks your stool for cells that are shed by colon cancers or precancerous polyps.
When should you be screened for colorectal cancer ?
Colorectal cancer is more common in older people, 50 years of age and older. Some people have risk factors that make them to get a colorectal cancer at a young age. Screening should begin earlier in these people.
You should be screened for colorectal cancer at a younger age if:
* you have had colorectal cancer or polyps in the past
* you have a family history of colorectal cancer or polyps
* you have ulcerative colitis or Crohn's disease
* you have a hereditary colon cancer syndrome
* you eat a high-fat, low-fiber diet
If you are in one of these groups, you need to be tested at a young age more than a person who doesn't have risk factors for colorectal cancer.
If you don't have any risk factors for colorectal cancer, you should have your first screening test around 50 years of age.
Any one of the screening programs with DRE at each screening are used, beginning at 50 years of age. There is no minimum age for having a screening colonoscopy.
If you want to do screening, discuss with your doctor what type of screening should you choose ?
