Everything you need to know about colorectal cancer screening
Colorectal cancer is the third most diagnosed cancer in the United States for both men and women, not including skin cancers. It is also the third leading cause of cancer-related death. The American Cancer Society estimates more than 150,000 cases of colorectal cancer will be diagnosed in the United States in 2022. Colorectal cancer screening, which should start at age 45, and a healthy lifestyle are the best ways to reduce your risk.
What is colorectal cancer?
Colorectal cancer is a group of cancers in the colon (colon cancer) or rectum (rectal cancer). The colon makes up most of the large intestine, a long muscular tube. The rectum is the last part of the large intestine that connects to the anus.
Most colorectal cancers start as small non-cancerous growths called polyps in the lining of the colon or rectum. Polyps can turn into cancer over time and grow into the walls of the colon or rectum. If not detected early, cancer cells can make their way into the blood and lymph vessels (small tubes that remove waste), as well as other parts of the body. When cancer spreads to other parts of the body, it is called metastasis.
A gastroenterologist can prevent colorectal cancer by removing polyps before they become cancerous rather than treating cancer that has spread in the body. This is why early and regular screening for colorectal cancer is essential.
Risk factors for colorectal cancer
Certain risk factors increase a person's chance of getting colorectal cancer, but it does not mean you will get colorectal cancer. However, it's important to talk with your medical provider about your risk factors and start screening for colorectal cancer at age 45. Some people without risk factors may still develop colon cancer or rectal cancer.
Some risk factors for colorectal cancer are out of your control. These include:
- Age — being age 50 or older
- A personal history or family history of colorectal polyps or colorectal cancer
- A personal history of inflammatory bowel disease (IBD), including Crohn's disease or ulcerative colitis
- Having a genetic condition like familial adenomatous polyposis (FAP) or Lynch syndrome (or hereditary non-polyposis colorectal cancer, or HNPCC)
- Having Type 2 diabetes
- Lineage — being African American and of Ashkenazi Jewish heritage
Colorectal cancer prevention
Some risk factors are in your control. Here are ways you can help prevent colorectal cancer:
- Eat a healthy diet
- Don't smoke
genetic testing if you have a family history of colorectal cancer
- Limit alcohol
- Stay active
Again, the most important thing you can do to prevent colorectal cancer is to start screening at age 45.
Colorectal cancer screening
The best form of prevention is to begin colorectal cancer screening at age 45 and continue with regular examinations. If you have high risk factors, you may need to start screening earlier. There are four main screening options. The best one for you depends on your personal risk factors. Your medical provider may also recommend getting more than one type.
A colonoscopy allows the clinician to see the entire colon in great detail. A thin, flexible tube with a camera and light is inserted into the rectum and colon to look for polyps or unusual tissue. The clinician may take small tissue samples (biopsies) and can remove any polyps they find.
You will need to clean your bowels with a clear liquid diet and strong laxatives before this colonoscopy.
Depending on the results of your colonoscopy, this type of screening is repeated every three to 10 years.
During this procedure, a clinician inserts a thin, flexible tube with a light and camera into the rectum and colon to look for polyps or other abnormal tissue.
The clinician will take a small tissue sample (biopsy) from any polyps found for further testing. Polyps may be removed during this procedure, or a colonoscopy may be scheduled to remove the polyps and examine the colon further.
If no polyps or other issues are found, this type of colorectal screening should be repeated every five to 10 years.
There are two common types of stool (fecal) sample tests. One type is a stool DNA test that looks for DNA markers connected to cancerous changes. The other type looks for blood in the stool which may be a sign of cancer.
Both types of colorectal stool sample screening can be performed at home and neither requires advanced preparation. After following the steps to collect a stool sample, you place it in special packaging and mail it to a laboratory for testing.
This type of colorectal screening needs to be repeated every one to three years. If the test results show signs of blood or abnormal DNA, your provider will likely order another type of screening, such as a colonoscopy.
At-home colorectal screenings are not for everyone
At-home colorectal cancer screenings, such as Cologuard,® can be a convenient way to check for colorectal cancer but there are some important risks to consider. At-come screening should not be used if you:
● Have a condition that places you at high risk for colorectal cancer, including inflammatory bowel disease (IBD), certain hereditary syndromes, or a family history of colorectal cancer
● Have a history of colorectal cancer, adenomas, or other related cancers
● Had a positive result from another colorectal cancer screening test within the last six months
Talk to your healthcare provider if any of these situations apply to you.
Also, a negative test result from an at-home screening does not confirm the absence of cancer. False positives and false negatives can occur. In a clinical study, 13% of people without cancer received a positive result (false positive) and 8% of people with cancer received a negative result (false negative).
Patients with a negative test result should always discuss the result with their healthcare provider and ask when they need to be tested again.
Colorectal cancer treatment
If a colorectal cancer screening detects cancer, the type of treatment will depend on the cancer stage (the location, size, and spread). Colorectal cancer treatment may include surgery, radiation, chemotherapy, or other treatments. Colorectal cancer found early is usually easier to treat, which is why early and regular screening is so important. People with early-stage colon cancer have a 91% five-year survival rate, and people with early-stage rectal cancer have an 89% five-year year survival rate.
Learn more about how Reid Health Cancer Center can help you prevent or treat colorectal cancer.