Dear NP

Dear NP,

I have a friend who was recently diagnosed with end-stage colon cancer at a young age. Please tell me what the recommendations are for colorectal cancer screening? Are there any options for screening besides having a colonoscopy?

Dear Reader,

Unfortunately, the rate at which people under 65 are diagnosed with colorectal cancer has been steadily increasing since the mid-1980s. About 12% of colorectal cases in 2020 are in people aged 65 or lower.

However, the rate at which older people get colorectal cancer has been decreasing. This decline is primarily due to more people getting the recommended screening tests. Screening for colorectal cancer is a critical component of prevention because screening can detect precancerous growths called polyps and remove them before they have a chance to explode into cancer.

Your instincts are right here – getting screened for colon cancer is never a bad idea. While the American Cancer Society’s official guidelines only recommend regular cancer screening for people with average risk starting from the age of 45, you have little to lose by getting started earlier.

Though the colonoscopy is the most common household name for colorectal cancer screening—and it is also the most comprehensive screening available – several options are somewhat less invasive that may be more appropriate for a younger person at a lower risk. Most of these methods involve a stool sample:

Fecal immunochemical test (FIT)

The purpose of this test is to look for occult (hidden) blood in a stool sample. Larger precancerous polyps contain fragile blood vessels that generally break during a bowel movement. However, the amount of blood is usually so small that it is invisible to the naked eye. Analyzing a sample in the lab can reveal this hidden blood, indicating the presence of polyps. This test is the most convenient screening because it can be done at home and has no dietary restrictions. Your healthcare provider will provide you with a kit with detailed instructions on how to collect the sample. Different kits have different instructions, but usually, it involves a small amount of stool from one or more bowel movements scraped onto a test card.

Guaiac-based fecal occult blood test (gFOBT)

This test is similar to the FIT test because it looks for hidden blood in the stool, but it relies on a chemical reaction. Because of this, there are certain foods or drugs you may be instructed not to eat before taking the test. These include non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil), naproxen (Aleve), or aspirin, vitamin C, and red meat. While this can make the test somewhat more complicated to schedule and take, your healthcare provider may recommend this test because it is highly sensitive.

Stool DNA test

This test looks for occult blood but also looks for abnormal sections of DNA from precancerous polyps. Unlike the other stool tests, this requires a full sample rather than a small scraping onto a card or into a tube. This method makes the stool DNA test the most comprehensive stool screening.

Virtual colonoscopy (CT colonoscopy)

Virtual colonoscopies mimic visual inspection of the colon that occurs during a colonoscopy, but it does so using CT scanning. This method is suitable for the patient because it does not require any sedation. However, it still requires the same type of bowel prep as a regular colonoscopy, which involves gradually consuming a laxative mixture that clears the colon. The virtual colonoscopy looks for whole polyps, just like a standard colonoscopy.

While all of these tests are effective early colon cancer screenings, none are as comprehensive as a real colonoscopy. Stool tests are subject to false positives, and if any of these tests come back positive, your healthcare provider will recommend a full colonoscopy to follow-up anyway. The colonoscopy is the only procedure that can also be used to collect polyps for further testing.

However, for a young person just taking precautions, one of these minimally invasive tests may be just what the doctor ordered.

Dr. Wesley Davis is an Emergency Nurse Practitioner at Crook County Medical Services District and Coordinator of the Family and Emergency Nurse Practitioner program at the University of South Alabama. He encourages readers to send their questions to [email protected]