Knowing the basics about colon cancer could one day save your life. While most people diagnosed with colon cancer are 65 or older, more young adults are being diagnosed with the disease, which is the second-leading cause of cancer death. In fact, by the year 2030, colon cancer is projected to be the leading cause of cancer-related death for people in their 20s, 30s and 40s.
The good news is that if you get screened, we have a very good chance to catch any potential signs of colon cancer in its early stages, when it is still treatable and curable.
Two categories of screening for colorectal cancer
You probably have heard about colonoscopy, the procedure that is performed by a doctor to check for colon cancer or polyps, which are small growths that can turn into cancer. UW Health offers two types of colonoscopy — traditional colonoscopy (also called optical colonoscopy) and virtual colonoscopy.
In recent years, another screening option has become increasingly popular for patients of average risk for developing colon cancer that allows you to test at home.
We recommend discussing colon cancer screening options with your primary care doctor. Ultimately, the best one for you is the one that gets done.
At-home, stool-based screening (Cologuard)
The at-home test involves sending a sample of your stool to a laboratory in a kit that is mailed to you at no charge. Your doctor will notify you of the result. If it is positive, meaning something unusual was found in your stool, you will be contacted to schedule a colonoscopy to determine whether cancer is present.
Cologuard may be a good option if you are at average risk for developing colon cancer. This means that:
You are at least age 45 and can answer NO to ALL of these questions:
Do you have a personal history of colon cancer, polyps or inflammatory bowel disease, such as Crohn’s disease or ulcerative colitis?
Do you have a family history of colon cancer (especially with a close relative, such as a parent, brother or sister)?
Have you ever had a positive result from any type of colon cancer screening?
Do you have a confirmed or suspected inherited colon cancer syndrome, such as Lynch syndrome or FAP (Familial Adenomatous Polyposis)?
Advantages of a stool-based test
A stool-based test is easy and convenient. You collect a sample of your stool at home, mail the sample back in the kit that is provided and that’s it. This video, from the makers of Cologuard, describes the process. There is no bowel preparation, sedation or need to take any time off from work.
It has a high detection rate. In studies, about 92% of those with a positive Cologuard result turned out to have colon cancer.
Disadvantages of a stool-based test
It is not recommended for high-risk people, such as those with a family history of colon cancer. Those at high risk should have a colonoscopy.
It is not perfect at detecting colon cancer. Studies have shown that about 8% of those who get a negative result (which is normally good news) turned out to have colon cancer. This test cannot prevent cancer by detecting pre-cancerous lesions, as it identifies them only 42% of the time.
It can produce a false positive result, meaning that a small number of people who use the at-home test are told they need to have an optical colonoscopy, when, in fact, they did not have any concerns in the first place.
If your at-home test is negative, it should be repeated every 3 years. In contrast, most people who have a negative colonoscopy result can wait between 5 and 10 years before having their next colonoscopy.
Optical colonoscopy: Detection and prevention at once
Optical colonoscopy, which has been widely used for nearly 50 years, is a test that looks not only for cancer, but polyps, which are growths along the lining of the colon that can turn into cancer. During the 30-to-60 minute procedure, which is done while you are under sedation, a doctor examines your colon using a flexible, lighted tube with a small camera at the end.
If the doctor finds any small polyps, they can usually be removed right away, making optical colonoscopy the only screening procedure that can also prevent cancer. If necessary, the doctor may take tissue samples — which are examined during a biopsy to see if they are cancerous.
Because the colon must be cleaned out before the procedure, you will need to do a “bowel prep” starting the day before the colonoscopy. This involves drinking only clear liquids, including a special solution that causes you to have bowel movements. This solution may be available over-the-counter or from a pharmacy.
Because of the sedation, you will need to have someone drive you home after the colonoscopy. You should also plan to rest for the remainder of the day.
Advantages of optical colonoscopy
It is the most thorough and most accurate way to screen for colon cancer. It has the highest detection rate, both for cancer and for polyps that could become cancerous.
It can both detect and prevent cancer. Doctors can find and remove pre-cancerous polyps during the procedure, stopping cancer before it even starts.
Most patients with a normal colonoscopy result do not need to repeat the procedure for 10 years.
It is the preferred screening method for high-risk patients, such as those with a family history of colon cancer.
Disadvantages of optical colonoscopy
It’s an invasive procedure because the doctor inserts a scope into your colon.
It requires a day of bowel prep, which can be unpleasant for some people.
You need to arrange for someone to drive you home and you probably need to take a day off of work so you can rest after the procedure.
Optical colonoscopy is very safe, however there are slight risks that include bleeding, infection, or rarely, a tear in the wall of the colon. Your doctor will discuss the risks with you.
Virtual colonoscopy: less invasive and no sedation
Virtual colonoscopy, also known as CT colonography, is colon cancer screening procedure that is less invasive, but just as accurate as optical colonoscopy. This procedure is only recommended for people at average risk of colon cancer or have no personal history of inflammatory bowel disease.
After the procedure, a radiologist will view still pictures and a “movie” of the inside of your colon through use of CT scan technology and 3D computer software. It allows doctors to obtain 3D images from different angles without inserting a scope into the colon.
UW Health was among the first health care organizations in the nation to offer virtual colonoscopy. Dr. Perry Pickhardt, a UW Health radiologist, was the primary investigator of a landmark study more than two decades ago that demonstrated the effectiveness of virtual colonoscopy.
Advantages of virtual colonoscopy
It is less invasive than optical colonoscopy and typically lasts no more than 30 minutes.
It can detect pre-cancerous polyps, which helps prevent cancer and can also find early cancers.
There is no need for sedation, so you can drive yourself home within a few minutes after the procedure.
You receive a phone call with your results the same day. If any large polyps or other concerns are found, UW Health makes every effort to schedule an optical colonoscopy the same day so you don’t have to do a second bowel prep.
The procedure can pick up abnormalities outside of the colon that otherwise may not be detected.
Disadvantages of virtual colonoscopy
You still need to do a bowel prep. On the day before the procedure, you can only have clear liquids. You also will be given liquids to drink that make you have bowel movements.
It can only detect polyps and tumors; it cannot remove them. If anything abnormal is found during the procedure, you will need to have an optical colonoscopy, which UW Health will try to schedule the same day.