Colorectal Cancer Detection and Diagnosis

Over the past two decades, there have been several advancements in colon and rectal cancer treatments. One particular area that has made positive strides is the development of screening programs aimed at the prevention and early detection of colorectal cancer. In addition to understanding your family history, it is important to stay on top of regular colorectal cancer screening. Even if you're feeling fine, it's important to be screened starting at age 45, according to the American Cancer Society.

There are several screening tests for colon and rectal cancers, including some that were recently made widely available. Take time to schedule an appointment with your primary care physician so you can learn more about your screening options.

Common Types of Screening for Colon and Rectal Cancers

There are 6 common types of screening options for colorectal cancers. These tests range from those that are performed at a healthcare facility, such as a colonoscopy, to those that can be conducted at home. Keep in mind that even though at-home testing offers more privacy, it can often lead to a false positive or a misinterpretation of the results. While you can’t exclusively use at-home tests for colorectal cancer screening throughout your life, you might be able to use this option first.

Watch to see a comparison of at-home colorectal cancer test kits versus a colonoscopy. 

The best method of screening depends on factors such as your age and risk for developing colon and rectal cancer. You can read our blog to learn more about colorectal cancer risk factors and who is at risk. Talking with your doctor can also help when it comes to making a decision on a screening test.

Healthcare Facility Testing

The following tests are ones that are conducted by a healthcare facility. Your doctor can help you determine which test is the best one for you.

Standard Colonoscopy

Colonoscopies continue to be the best approach for detecting colon and rectal cancer. This test involves the use of a flexible lighted tube called a colonoscope. Inserted into the rectum, the colonoscope features a lens for viewing and a tool for removing tissue. Air is inserted into the rectum, helping doctors to better view the colon lining. If any abnormal growths are identified, they can be removed for testing during this procedure. Your doctor might also sample tissues during this procedure for additional testing. 

A thorough cleansing of the colon prior to testing as well as being sedated during the test, are two important steps that help contribute to a successful colonoscopy. According to the National Cancer Institute, studies show that colonoscopy screenings can reduce colorectal cancer deaths by as much as 60-70%. Because of this, colonoscopy is often the preferred screening test for early detection. A key benefit of a colonoscopy is the ability to view the entire colon.

Virtual Colonoscopy

With this test, a CT scanner takes images of the colon. This test typically does not require sedation; however, it does require bowel preparation. During the test, the air is pumped into the colon and rectum, which makes it possible for the scanner to show detailed, cross-sectional images. If the doctor sees polyps or possible cancer, a standard colonoscopy may be ordered for confirmation. 

Patients at average risk for colon cancer and who are age 45 and older are ideal candidates for a virtual colonoscopy. A doctor may also order a virtual colonoscopy if there is a bowel obstruction or you are at risk for complications from a regular colonoscopy.

Flexible Sigmoidoscopy

Similar to a colonoscopy, this test looks only at part of the colon. In most cases, there is no need for sedation during a flexible sigmoidoscopy test. Doctors can either remove polyps during the test or order a colonoscopy. Although bowel preparation is necessary, it is not as extensive as that required for a colonoscopy.

At-Home Testing

The following tests are ones you can do in the privacy of your own home. Ask your doctor about which test, if any, is right for you.

Stool DNA Test

A stool DNA test can be requested by patients who want to avoid the preparation and invasive testing of a colonoscopy. Using a take-home test kit provided by their doctor, patients collect a stool sample and mail it to a lab. The test checks for blood in the stool and gene changes.

Although stool DNA tests are convenient and non-invasive, they are not for everyone. This type of testing should be reserved for only those with an average risk for colon or rectal cancer. If the test results are abnormal, additional testing through colonoscopy may be needed.

Guaiac-based Fecal Occult Blood Test (gFBOT)

This test can be picked up from your doctor and taken home. After a stool sample is collected onto a test card, the card needs to be returned to the doctor's office for testing. Because tiny amounts of blood can go unseen by the naked eye, high-sensitivity blood tests, such as the gFBOT, can be an incredibly valuable screening tool. gFBOT uses a chemical to detect heme, a component of the blood protein hemoglobin. Since this test may detect heme in certain foods, such as red meat, patients are often required to eat a special diet prior to screening.

Fecal Immunochemical Test  (FIT)

This test uses antibodies to specifically detect the human hemoglobin protein. There are no dietary restrictions prior to testing like there are with the gFBOT.

Screening Recommendations for Colorectal Cancer

The American Cancer Society (ACS) recently lowered the recommended screening age from 50 to 45 for colon and rectal cancer.

This new recommended age resulted from research that found increasing cases of colon and rectal cancers among younger adults. Research remains ongoing; however, several contributing factors attributed to the increase are poor diets, lack of physical activity, and obesity.

Screening recommendations for colon and rectal cancer differ based on whether a patient is at average risk or high risk for the disease. Patients who are at average risk tend to have no family history of colorectal cancer and are, on average, fairly healthy. The ACS recommends that average-risk patients undergo a thorough screening every ten years.

Patients considered at high risk for colorectal cancer often have one or more of the contributing factors:

• A family history of colon or rectal cancer
• Problems with inflammatory disease
• Radiation to the pelvic area from a previous cancer

The ACS recommends beginning screening earlier than age 45 and scheduling screenings more frequently than every 10 years for high-risk patients. Prevention through regular screening is key and especially important for those at high risk of developing colon or rectal cancer.