What’s New in the World of Colon Cancer Screening?

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April 7, 2019

March was colon cancer awareness month. I am a little late in my blog this year but want to give a shout out to getting screened – you can prevent or detect this cancer early with a colonoscopy.

Colon cancer is the 2nd most common cause of cancer death in the US, with approximately 50,000 people expected to die from colon cancer this year. Colon cancer deaths have dropped over the past couple of decades presumably due to screening, yet we still are short of the GI society goals of screening at least 80% of the average risk population.

Symptoms of colon cancer include change in one’s usual bowel pattern, rectal bleeding, abdominal pain, unexplained weight loss, or the development of anemia (low blood count). They often don’t develop until colon cancer is more advanced. That is why screening is so important. Several options are available for screening average risk persons, but colonoscopy is the method recommended for those who are at higher risk (those with a history of polyps, with a family history of colon cancer or polyps, history of ulcerative colitis or Crohn’s disease or those with a genetic predisposition to colon cancer) and those with symptoms. It is the most sensitive test, and the only one that allows for removal of polyps (small growths), some of which can grow into cancer over time. It is the only test that can prevent colon cancer (by removing the polyps). It is important to let your doctor know of any of the risk factors noted above, so that they can advise you as to what age to have your first colonoscopy, and how often a colonoscopy is needed in your situation.

Let’s look at what’s new in screening, then I’ll mention other options.


AGE CHANGE: The American Cancer Society recently recommended starting screening at age 45 for all average risk patients. The previous recommendation was to start at age 50 except for African Americans ( at age 45) who are known to develop colon cancer earlier. Although the incidence of colon cancer has been decreasing in those aged 50 and older, it has been rising in those younger than 50. Screening colonoscopies are currently fully covered by insurance and not subject to deductibles and copays, under the Affordable Care Act. Recently 2 insurances in our area have begun covering people under the age of 45 for screening colonoscopies. I suspect that others will do so over time.

PREP NEWS: Low volume preps are being offered more often, meaning that there is less to drink to clean out the colon. If you wish to drink less of a laxative, I suggest asking if that prep would work for you. Research has shown that patients may be able to eat a little bit of certain foods rather than drinking only clear liquids the day before the test thus some gastroenterologists are liberalizing the pre-colonoscopy diet in selected patients. Follow your own doctor’s instructions.

LESS SURGERY: When I first started in practice, any patient with a large polyp which couldn’t be removed through a standard colonoscopy would need surgery. Now if I find a large polyp that I can’t remove, I can send my patient to a therapeutic endoscopist, who can remove it through a colonoscope with special equipment, therefore avoiding surgery.

TESTING BETWEEN COLONOSCOPIES: Should patients have stool checked for blood in between colonoscopies? That has not been studied in a controlled prospective fashion, but a recent study did show that patients with positive stool tests after colonoscopy were more likely to have polyps or cancer than those with a negative stool test and the risk went up, as expected 3-10 years after negative colonoscopy. Primary care doctors may choose to have you get your stool checked for blood starting a few years after your colonoscopy.

RISK CALCULATORS FOR PATIENTS AND DOCTORS: Some patients who are not high risk by current criteria, but may benefit from more frequent screening include those who are obese, have diabetes, smoke, eat red meat, are inactive, or have a diet low in fruits and vegetables. There are screening decision-making tools that take those factors into account and calculate the relative risk that a specific person will develop colon cancer. I have not yet used them in my practice but looked at them for this blog. An easy one to use is: www.cancer.gov/colorectalcancerrisk.

So, what is the best screening test for YOU, if you are over 45-50 years old and at average risk of having colon cancer? Although the colonoscopy is the gold standard, any of the available tests are useful if performed properly with appropriate follow up.

IFOBT or immunofecal occult blood testing refers to a stool sample that a patient places on a little stick and sends back to the lab or to their doctor’s office. If blood is detected, a colonoscopy is needed to determine if colon cancer or polyps are present. If no blood is detected, the IFOBT should be done every year.

The COLOGUARD test requires that a piece of stool be mailed in a special container to a lab. The lab analyzes the sample for blood and for DNA that is shed from tumors and polyps. An abnormal Cologuard test needs to be followed by a colonoscopy to determine if a patient has colon cancer or polyps. If a Cologuard is normal, it should be repeated every 3 years.

CT COLONOGRAPHY is commonly known as virtual colonoscopy. Laxatives are used to clean the colon for the test and patients are awake while air and fluid are inserted into the rectum. Abnormalities need to be followed by another bowel prep and colonoscopy. CT colonography would need to be done every 5 years, raising concerns of excessive radiation exposure.

Risks and benefits of these options should be discussed with your doctor.

So, March is over, have YOU been screened?