Colonoscopy

Colonoscopy not only allows for the most thorough evaluation of the colon and identification of polyps and other problems, but also allows for diagnosis, treatment, and removal of potentially precancerous polyps. Colonoscopy is the only colorectal cancer screening tool that is both diagnostic and therapeutic. A complete bowel cleansing is required before the exam. Colonoscopy is generally done with sedation and is well tolerated. Patients are given medicine that is injected through a vein to make them feel relaxed and sleepy. Most people do not remember the actual procedure.

Colonoscopy is performed using a colonoscope, a thin, flexible tube with a light and a very small video camera on the end, which allows the doctor to see the entire colon. If a polyp or abnormality is found, the doctor can remove or sample it using devices that go through the colonoscope. These devices include small biopsy forceps or a loop of wire called a snare. The removed tissue is sent to the pathology lab for evaluation.

Colonoscopy is the most commonly used screening test for colorectal cancer because it has a high rate of detecting precancerous polyps and enabling their removal.

PROS of Colonoscopy

• Examines the entire colon
• High detection rate for polyps, including small polyps, and ability to remove them immediately during the procedure
• Done with intravenous sedation to assure comfort during the exam
• Average risk patients with normal results need not repeat the test for 10 years
• Given the "Gold Standard" rating above all other screening options by: American Society for Gastrointestinal Endoscopy (ASGE), American Gastroenterological Association (AGA), American College of Gastroenterology (ACG), the American Cancer Society (ACS), and the American College of Obstetricians and Gynecologists (ACOG).

CONS of Colonoscopy

• Requires a complete bowel prep the night before to cleanse the colon
• Unexpected events or complications are rare, but do occur and may include:
• Missing a lesion
• Making a tear in the lining of the colon, which is called perforation
• Bleeding
• A bad reaction to the medication used for sedation

Fecal Immunochemical Testing

FIT is newer kind of test for hidden blood in the stool. It is a non-invasive, at-home test that detects about 79 percent of colorectal cancers and 30 percent of large colorectal polyps. Because FIT is not as effective as colonoscopy at finding cancer or polyps, it should be done every year. The at-home screening kit is sent to a lab for testing, and people who have a positive result (blood detected) will need to undergo a colonoscopy. FIT has a false positive rate of about 5 percent. The cost of the test is about $25.

PROS of FIT

• Simple
• Cost-effective
• Done at home

CONS of FIT

• Must be done yearly
• Can miss up to 21 percent of cancers and 70 percent of large polyps
• False positive of 5 percent
• Viewed as unsanitary by some
• Patient must retrieve samples of stool from the toilet bowl
• All positive results MUST BE EVALUATED WITH A COLONOSCOPY

FIT-Fecal DNA Test

What it is:

• The currently available FIT-Fecal DNA test is Cologuard^®. This is a stool-based screening test for colorectal cancer that is used for people at average risk for colon cancer who are age 50 years or older. The cost is typically around $600.
• If positive, this test should be followed up with colonoscopy.
• If negative, this test should be repeated in three years.

What it's NOT:

• A test for patients who have previously had colorectal polyps or cancer
• A test for patients with a strong family history of colon cancer

Other facts about Cologuard:

• It costs 20-30 times more than the other stool screening test (FIT) with only a modest improvement in performance.
• If positive, a diagnostic colonoscopy should be performed to determine if polyps or cancer are present in the colon. Insurance coverage may be less for diagnostic colonoscopy than for colonoscopy performed as the initial screening test. Patients should check with their health insurance company to understand how screening vs. diagnostic tests for CRC are covered.
• It should be performed every three years, whereas screening colonoscopies can be performed every 10 years in people without any polyps or cancer history.
• It has a high false positive rate–especially in older patients.

Stool Blood Test (Fecal Occult Blood Test)

This is a stool sample test that tries to find small amounts of hidden (occult) blood in the feces. People having this test will receive a kit with instructions that explain how to take stool samples at home. The kit is then sent to a lab for testing. If the test is positive, further tests will be done to pinpoint the exact cause of the bleeding. A rectal exam in the doctor's office may examine for occult blood, but this is NOT considered adequate for colorectal cancer screening. The test should only be done with a take-home kit.

PROS

• Simple
• Cost-effective
• Done at home

CONS

• Must be done yearly
• Least effective means of detecting cancer
• Viewed as unsanitary by some
• Patient must retrieve samples of stool from the toilet bowl
• All positive results MUST BE EVALUATED WITH A COLONOSCOPY

Flexible Sigmoidoscopy (FLEX-SIG)

A sigmoidoscope is a slender, flexible tube with a light and a very small video camera at the end of it. It is shorter than a colonoscope, and is only able to evaluate the lower third of the colon. This allows the physician to look at the inside of the rectum and lower part of the colon for cancer or polyps. Before the test, you will need to take an enema or other prep to clean out the lower colon, but a full cleansing solution is not needed as in colonoscopy. This test is often done without any sedation, so it can be uncomfortable, but it should not be painful. If a flex-sig test is performed, it should be repeated every five to ten years.

PROS of Flex-Sig

• Quick: usually a one- to five- minute exam
• Does not require a vigorous bowel prep
• Does not require sedation

CONS of Flex-Sig

• Two-thirds of the colon are not examined
• If polyps are found, the patient MUST RETURN FOR A FULL COLONOSCOPY, as the remainder of the colon will need to be examined.

Virtual Colonoscopy (CT Colonography)

This is a special CT scan study that is used to image the colon. A small tube is placed in the rectum and air flows into the colon to inflate the bowel. A special CT scan is then used to take an image of the colon. Recent studies show that it is effective in identifying medium to large polyps, but it is ineffective in identifying small polyps and it may also miss flat polyps. CT colonography may be best for low-risk patients who cannot undergo a conventional colonoscopy, or whose colonoscopy could not be completed. The same bowel prep as conventional colonoscopy is required but it does not require sedation.

PROS

• Examines the entire colon
• High detection rate for medium to large polyps
• Low risk
• Patient with a normal result can repeat the test in five years

CONS

• Air distention of the bowel can be uncomfortable
• Ineffective in detection of small polyps
• Uses X-ray radiation
• If polyps or other abnormalities are found, A COLONOSCOPY MUST BE PERFORMED
• Is not covered by Medicare or most other insurers as an initial screening test
• Evidence is lacking that it lowers the incidence of colorectal cancer or mortality