LMS President’s Message, April 2019
Colon Cancer Screening and Prevention – Let’s Shoot for Best in the U.S.A
By Charles L. Papp, MD
As LMS President, I suppose I am on occasion allowed to use my presidential bully pulpit. We have just completed the month of March, which some of you may know has been designated Colon Cancer Awareness Month. As a colon and rectal surgeon, I would like to use that bully pulpit to talk about colon cancer screening and prevention.
Colorectal cancer is common, lethal, and often preventable. Some of you may have a friend or relative with colorectal cancer, and a few of you may have dealt with it personally. I suspect all of us have patients who have had the disease. By the law of averages, one out of 20 people will develop colorectal cancer — or, to make it more personal, we have a 4% to 5% chance of developing the disease in a lifetime. To make matters worse, it is currently the second most common cause of cancer death in the United States. Because it is felt to be preventable in up to 60% of cases, we as physicians can make a difference
The American Cancer Society recognizes 6 options for screening:
1) fecal immunochemical test (F.I.T.) annually;
2) high-sensitivity, guaiac-based fecal occult blood test annually;
3) stool DNA test (such as Cologuard) every 3 years;
4) colonoscopy every 10 years;
5) computed tomography colonography every 5 years; and
6) flexible sigmoidoscopy every 5 years. Because screening leads to the removal of precancerous polyps and often can detect a cancer at an earlier stage, the incidence and mortality can and has been significantly reduced.
For many years, screening for colon and rectal cancer was recommended to begin at age 50 for low-risk patients. The American Cancer Society has now lowered this recommendation to age 45 based on studies that suggest those born after 1990 have double the risk of colon cancer and quadruple the risk of rectal cancer. I have included a link to one of the main articles for those who are interested. This recommendation has not been taken up by the U.S. Preventive Services Task Force yet and may not as yet be approved by some insurance plans.
When it comes to screening, I obviously push for colonoscopy in patients with an acceptable risk. It is the most sensitive and specific of the screening methods. In addition, screening colonoscopy is usually covered 100% by insurance without copay or deductible. If pathology is found, it can be removed or biopsied at the time of screening. There are downsides, such as the bowel prep, time off work, risk of missed polyps, and the small chance of complication. There is a 4 in 10,000 risk of perforation and an 8 in 10,000 risk of major hemorrhage.
Computed tomography colonography (virtual colonoscopy) is less invasive but still requires a full bowel prep. There are fewer risks of complications, and it provides information about other abdominal and pelvic organs. If pathology is found in the colon, the patient still requires a standard colonoscopy, which may mean another bowel prep. As with standard colonoscopy, polyps can be missed, and it seems the rate of missed polyps may be higher for those that measure less than 1 cm. In addition, flat polyps may be hard to detect.
The fecal DNA test (such as Cologuard) does not require a bowel prep, is convenient, and is covered by Medicare for eligible patients. It costs approximately $649 and should be repeated every 3 years. It unfortunately misses 8% of cancers and 60% of advanced polyps. Also, it has a 13% false- positive rate, leading to colonoscopy referral in patients who end up not having a lesion.
F.I.T. uses immunochemistry to detect occult blood, while guaiac fecal occult blood depends on a chemical reaction. The F.I.T. has a higher sensitivity than guaiac, and there is a greater compliance because F.I.T. only requires one sample, as opposed to the 3 separate samples needed for stool guaiac. As more studies show superior results, F.I.T. is becoming the preferred occult blood screening test. If the test is positive, the patient will need a colonoscopy. In terms of screening, the rate of missed polyps is higher than colonoscopy.
Flexible sigmoidoscopy requires a bowel prep, only looks at the left colon, and is uncomfortable since it is usually performed without sedation. It is not now used commonly for colon cancer screening.
When it comes to prevention, there are several factors that can affect the risk of developing colon cancer. It is clear that maintaining a healthy weight, getting regular exercise, limiting red and processed meat, and increasing fruits and vegetables are effective in lowering risk. Alcohol and smoking have been found to increase risk. The American Cancer Society recommends less than 2 drinks a day for men and 1 drink a day for women. Some recommendations that need further study include vitamin D, calcium, and magnesium. Nonsteroidal drugs may also have a preventative effect but also come with other risks.
The best preventative is regular screening. For someone with average risk, consider beginning screening at age 45. Those with a family history of colon cancer or a personal history of inflammatory bowel disease or polyps may need to start screening earlier and shorten the interval between screenings. Here is a link to screening guidelines for those who want more details.
Kentucky has been nationally recognized for moving from 49th place in colon cancer screening to 19th. This is a tremendous achievement. According to Dr. Thomas Tucker, Director of the Kentucky Cancer Registry at the University of Kentucky, “We were able to reduce the incidence of colorectal cancer by 24% and the mortality rate by 30% in just 7 years. No other state had such a dramatic change in such a short period of time.” I am proud of the progress Kentucky physicians have made. You have worked hard, our patients have benefited, and we are being noticed. Let’s keep it up. 19th place is good, but hey we’re Kentucky. Let’s shoot for number one.