4 Colorectal Cancer Early Screening Tests That Aren't Poop Tests

Of the possible cancers, colorectal cancer remains one of the most preventable, especially if it is detected early enough. The slow development of cancerous polyps in the colon and rectum, along with a variety of risk factors that lead to colorectal cancer mean that regular screening is recommended once you reach a certain age, usually your 40s if you are of average to low risk.

Unlike other screening and detection methods, initial screening for colorectal cancer doesn’t rely on radiation-based visualizations such as x-rays or computed tomography (CT) scans, and as such doesn’t pose any radiation risk.

Colonoscopy is considered the gold-standard detection and diagnostic test for colorectal cancer, which allows doctors to detect, identify and visualize polyps in the intestinal lumen in real time.

Other commonly used screening methods typically apply to average-risk individuals who do not have any symptoms of colorectal cancer. These tests look for blood and/or abnormal DNA in the stool. While inexpensive, self-administered and usually stool-based, the accuracy of these tests can vary due to cross-contamination and differing test sensitivities.

Nonetheless, given the impact that early detection has on preventive action, new screening methods are constantly being developed and tested.

Rather than stool, many alternative colorectal cancer early detection kits rely on one’s blood work to determine cancer risk. Different biomarkers such as genetic material or proteins are found in the blood, which, when presented in unique combinations, become indicators of different health conditions.

Like stool-based kits, many blood-based tests — also referred to as liquid biopsies — are non-invasive and require only a small sample of blood for testing.

1. ColoFast: Detecting microRNA in the blood

Funded by the EU, ColoFast* is a blood-based cancer screening kit that harnesses microRNA (miRNA) technology. miRNA are short genetic sequences of about 22 nucleotides long found in cells and the bloodstream when they are released by tumor cells and premalignant lesions. Individuals with colorectal cancer or premalignant lesions known as advanced adenomas can be differentiated from healthy individuals based on the levels of miRNA detected in the blood plasma.

While the test will not be available for mainstream use until 2024, present results indicate that ColoFast is a highly specific, sensitive and accurate test that provides results in relatively short periods of time. These easily implemented tests are also expected to be cost-effective and easily available, preluding a shift in the current standards of colorectal cancer screening.

*ColoFast is not FDA-approved.

2. Epi proColon®: Detecting methylated DNA in whole blood samples

Currently the first and only FDA-approved blood-based colorectal cancer test, Epi proColon™ also relies on detecting genetic material found in the blood. Unlike ColoFast, Epi proColon™ identifies DNA — specifically the SEPT9 gene — that has undergone methylation. Multiple studies have shown that the methylation of specific genes are linked with promoting cancerous growth in the colon through the silencing of tumor-suppressor genes.

The SEPT9 gene encodes for the protein septin-9, which is involved in various biological processes, and is also known to have tumor-suppressing characteristics. As such, suppression of the SEPT9 gene through methylation may account for the development of colon lesions from a benign to malignant state.

3. Galleri™: The multi-cancer blood test

Unlike many other screening tests that are focused on a single cancer, Galleri™ is a multi-cancer detection test that flags up the presence of cell-free DNA (cfDNA) in the bloodstream. By using both sequencing technology and artificial intelligence (AI), a Galleri test is capable of detecting indicators for 50 different cancers with a promising show of accuracy and sensitivity in identifying the location of the tumor.

The prescription-only test kit presents opportunities for healthcare providers to more accurately recommend follow-up diagnostic tests based on the Galleri screening results.

4. GI Genius: Enhancing colonoscopy with AI

The final screening tool on this non-exhaustive list is neither a blood-based nor stool-based test. GI Genius is a device that uses machine-learning driven AI to detect lesions in the colon during a colonoscopy.

While colonoscopy is still the benchmark colorectal cancer detection and diagnosis method, the tool is not 100% foolproof and smaller polyps and lesions can still go undetected. Designed to be compatible with existing colonoscopy systems, GI Genius uses AI to highlight areas of the large intestine when a potential lesion is detected. System-generated markers in the form of green squares with a short, low-volume sound are superimposed on the colonoscopy video when a lesion is identified. These indicators signal that further assessment or follow-up through visual inspection or biopsy may be required.