Colorectal cancer is a type of cancer that develops in the colon or rectum. It is the third most common cancer in the world, with over 1.8 million new cases diagnosed in 2018 alone. While the incidence of colorectal cancer has been declining over the past few decades, it is still a major public health concern. Fortunately, there are effective screening tests available that can detect colorectal cancer early, when it is most treatable. Colorectal cancer is one of the most common types of cancer that affects both men and women.
According to the American Cancer Society, it is estimated that over 100,000 new cases of colon cancer and over 40,000 new cases of rectal cancer will be diagnosed in the United States in 2023. The good news is that colorectal cancer can be prevented or detected early through regular colorectal cancer screening.
What is Colorectal Cancer Screening?
Colorectal cancer usually develops slowly over many years, and it may not cause any symptoms until it has reached an advanced stage. Early detection of colorectal cancer is crucial because it allows for more effective treatment and a better chance of survival. In fact, the five-year survival rate for patients with localized colorectal cancer is over 90%, while the five-year survival rate for patients with advanced-stage colorectal cancer is less than 14%.
Colorectal cancer screening can detect precancerous growths called polyps, which can be removed before they turn into cancer. It can also detect colorectal cancer at an early stage when it is more treatable. Screening can help reduce the number of deaths from colorectal cancer by up to 60%.
Colorectal cancer screening is the process of looking for cancer or precancerous polyps in the colon or rectum before symptoms appear. Screening can help detect colorectal cancer at an early stage when it is most treatable or prevent it altogether by identifying and removing polyps. There are several different types of screening tests available, including:
- Fecal Immunochemical Test (FIT): The faecal immunochemical test is a non-invasive test that looks for blood in the stool. It is usually done at home and involves collecting a small sample of stool with a kit provided by your doctor. The sample is then sent to a lab for analysis.
- Stool DNA Test: The stool DNA test is another non-invasive test that looks for DNA changes in cells that are shed into the stool. It is also usually done at home and involves collecting a small sample of stool with a kit provided by your doctor. The sample is then sent to a lab for analysis.
- Flexible Sigmoidoscopy: The flexible sigmoidoscopy is an invasive test that uses a thin, flexible tube with a light and camera at the end to examine the rectum and lower part of the colon. During the test, your doctor can remove polyps or take tissue samples for further testing.
- Colonoscopy: Colonoscopy is an invasive test that uses a long, flexible tube with a camera and light at the end to examine the entire colon and rectum. During the test, your doctor can remove polyps or take tissue samples for further testing.
When Should You Get Screened for Colorectal Cancer?
The American Cancer Society recommends that people at average risk of colorectal cancer start regular screening at age 45. People with a family history of colorectal cancer or other risk factors may need to start screening earlier or get screened more frequently. Your doctor can help you determine when and how often you should be screened based on your individual risk factors.
What Happens During Colorectal Cancer Screening?
The specifics of what happens during colorectal cancer screening will depend on the type of test you are having. Some tests, like the faecal immunochemical test and stool DNA test, can be done at home. Other tests, like flexible sigmoidoscopy and colonoscopy, are done in a medical facility.
Fecal Immunochemical Test and Stool DNA Test
If you are having a faecal immunochemical test or stool DNA test, you will be given a kit to collect a sample of your stool at home. The kit will come with instructions on how to collect the sample and how to send it to the lab for analysis.
If you are having a flexible sigmoidoscopy, you will need to prepare your colon by following a special diet and taking laxatives or enemas to empty your bowels before the test. During the test, you will lie on your side while your doctor inserts a thin, flexible tube into your rectum and slowly guides it into your colon. The tube has a camera and light at the end, which allows your doctor to examine the lining of your colon for polyps or signs of cancer. If your doctor finds polyps during the test, they can remove them or take tissue samples for further testing.