Your Health: What to know about colorectal cancer screening
Regarding colorectal cancer, perhaps the most effective way to remain healthy is to stay in the know with one simple but powerful solution: screening. Several low-risk procedures can ensure early detection and treatment. As the third most common cancer diagnosed in the United States, the American Cancer Society estimates there will be more than 150,000 new colorectal cancer cases this year alone. A number of screening options are available to ensure this personal decision is made with care and consideration.
Who should get screened for colorectal cancer?
Colorectal cancer typically affects older adults, though it can happen at any age. It usually begins as small, noncancerous polyps forming inside the colon. Over time, if undetected, these polyps can become cancerous. The good news is the death rate has been dropping for several decades, thanks to preventive screening. Colorectal polyps are now being found more often and removed before developing into cancers. Screening also reveals many colorectal cancers earlier, making them easier to treat. The CDC recommends adults aged 45 to 75 be screened for colorectal cancer. Those over age 75 should consult their doctor for screening recommendations.
Screening options
There are several screening options for colorectal cancer. Because they have different accuracy and detection rates, you should choose your screening method carefully in consultation with your primary care provider.
A colonoscopy is the gold standard for catching and preventing colorectal cancer over other screenings, like home-based tests. In addition to identifying approximately 95% of colorectal cancers, a colonoscopy is the only screening method that allows a gastroenterologist to detect and remove potentially precancerous polyps, lessening the need for additional procedures. Colonoscopies are considered low-risk procedures where the entire colon is carefully examined. Patients must clean their colon before the procedure by drinking a colonoscopy prep. The procedure is performed in a medical setting under sedation, where patients remain sleepy and comfortable throughout their colonoscopy. Depending on the results, patients may not need to repeat the colonoscopy for 10 years.
If you cannot tolerate the sedation or anesthesia, your provider may choose flexible sigmoidoscopy, where a camera is used to look at the rectum and the lower part of the colon. The advantages of this procedure are that it is quicker than the colonoscopy (only five to 15 minutes) and requires fewer prep medications. Patients receive a flexible sigmoidoscopy every five years if no polyps are detected. As this test does not examine the whole colon, it cannot detect cancers or polyps in the unexamined upper colon. The detection rate is only 70%, considerably lower than the 95% colonoscopy detection rate. A follow-up colonoscopy is needed to examine the entire colon if an abnormality is detected.
Another option sometimes used is the fecal immunochemical test (FIT). FIT testing is noninvasive, convenient, and cost-effective, making it an acceptable alternative to a colonoscopy. This lab test looks for hidden blood in the stool. Patients use an at-home kit to collect their stool, which is then placed into a tube and mailed to the lab. FIT testing is repeated every year. While it can effectively rule out colorectal cancer with 79% accuracy, one drawback is its false positive rate of approximately 5%.
Lastly is the Cologuard test. Like FIT, patients collect stool at home utilizing a container with preservatives and mail it to a lab. This test looks for atypical DNA or traces of blood that may suggest precancerous polyps or colorectal cancer. Typically, patients repeat the test every three years. Cologuard’s accuracy is limited; 13% of the time, the test indicates the patient may have cancer when they do not. Again, if you test positive on a home-based screening test, you will still need to schedule a colonoscopy to confirm the results and have any cancerous or precancerous polyps removed.
The bottom line, get screened
The most important part of colon cancer screening is to simply perform a screening test. When cancer is detected before it can metastasize, the five-year chance of survival for colorectal cancer is approximately 90%. For most patients, colonoscopy or FIT testing is the most common way chosen by providers to screen for colon cancer. Ultimately, this is a personalized decision and a discussion for you to have with your primary care provider. You can discuss the pros and cons of all the options so that the right test can be done at the right time. To find a primary care provider, visit pardeehospital.org.
Dr. Praveen Vashist is a board-certified hematologist and oncologist for Pardee UNC Health Care.
This article originally appeared on Hendersonville Times-News: Your Health column; The importance of colorectal cancer screening.
