New Screening Tests Ring in National Colorectal Cancer Awareness Month

Mar. 12, 2008 — A new guideline on colorectal cancer screening was released last week by an expert group representing a broad spectrum of health care organizations, including the American College of Gastroenterology (ACG), the American Society for Gastrointestinal Endoscopy (ASGE) and the American Cancer Society (ACS).

The guideline, which was released to coincide with March's National Colorectal Cancer Awareness Month, offers recommendations for different options for colorectal cancer detection and emphasizes the prevention of colorectal cancer through screening.

The recommendations add two new screening methods to the other options available to the consumer. Stool DNA testing and CT (computed tomography) colonography, also known as virtual colonoscopy, are the newly endorsed tests. Both are less invasive than other screening tests and should encourage patients to have tests that can find both polyps and most cancers.

Colorectal cancer is the third most common cancer diagnosed in men and women in the US. It is also the second leading cause of death from cancer.

"We know that 50 percent of Americans who should be getting screening for this largely preventable disease are not," says Dr. Grace H. Elta, president of the ASGE. "The data show that screening saves lives and efforts to increase colon cancer awareness and screening will help patients through earlier detection."

Even though rates of colorectal cancer have been declining over the past few years, they could be even lower if all people who should be screened actually get screened.

About the Tests
The stool DNA test is used to check for specific changes in DNA that are typically found in colon cancer. All the patient needs to do is collect an entire bowel movement, then the sample is sent to a laboratory.

Since the stool DNA test is fairly new, more research is needed to determine how often the test should be done to have the best possibility of finding cancer. Also, the test may be limited in finding every DNA change associated with cancer.

A virtual colonoscopy uses a CT scan to search for abnormal masses. It does not require the insertion of the tube with a camera on the end into the rectum, which is what happens in traditional colonoscopy.

According to the ACS, the new guidelines outline four testing procedures that are most likely to detect both polyps and cancer. They are:

• flexible sigmoidoscopy every five years



• colonoscopy every 10 years



• double contrast barium enema every five years



• CT colonography (virtual colonoscopy) every five years

A flexible sigmoidoscopy is a diagnostic procedure that allows the physician to examine the inside of a portion of the large intestine, and is helpful in identifying the causes of diarrhea, abdominal pain, constipation, abnormal growths, and bleeding. A short, flexible, lighted tube, called a sigmoidoscope, is inserted into the intestine through the rectum.

A colonoscopy is a test that uses a long, flexible tube with a light and camera lens at the end (colonoscope) to examine inside the large intestine.

Colonoscopy Still the Best Option
In spite of the experts' recommendations for the use of newer technologies to screen for colorectal cancer, the groups continue to agree that colonoscopy is the preferred method of screening, as in the past. Colonoscopy has great sensitivity in both detecting polyps and removing them, making the procedure both diagnostic and therapeutic.

Colonoscopy is considered to be one of the most effective preventive tools in clinical medicine.

Follow-up for Suspicious Findings
If there are any positive findings from stool tests, barium enema exams, or CT colonography, follow-up will be required.

For a positive result from a stool test, a follow-up colonoscopy will also be required.

If physicians discover adenomas (benign growths which often appear on glands or in glandular tissue) during sigmoidoscopy, that procedure should be followed by colonoscopy. This is because research suggests that patients who have an adenoma of any size in the colon are at an increased risk for developing cancer cells higher up in the colon.

Following CT colonography, the new guidelines states that the risk for patients whose polyps are small (smaller than 5 millimeters, or about 0.2 inch) is low, but for larger polyps (over 5 mm.) a follow-up colonoscopy is recommended.

Always consult your physician for more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Cancer Society

American College of Gastroenterology

American Gastroenterological Association

American Society for Gastrointestinal Endoscopy

National Cancer Institute (NCI)

Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology