Fola May, MD, PhD, is an associate professor at the David Geffen School of Medicine and associate director of the UCLA Kaiser Permanente Center for Health Equity.

Folasade (Fola) May, MD, PhD

The Nuances of Noninvasive Screening for Colorectal Cancer, with Fola May, MD, PhD

As colorectal cancer screening options expand, patients are faced with more choices than ever before—each with different strengths, limitations, and implications for care. While the growing menu of tests increases accessibility, understanding the nuances between them is essential for informed decision-making.

“Fundamentally, these tests are different,” Fola May, MD, PhD, an associate professor at the David Geffen School of Medicine and associate director of the UCLA Kaiser Permanente Center for Health Equity, told 

, emphasizing that the decision should be tailored to the patient’s preferences.

Despite the emergence of several new noninvasive tests, colonoscopy remains the most comprehensive screening tool, offering both preventive and diagnostic benefits by allowing physicians to find and remove precancerous polyps and detect cancers directly. For those unable or unwilling to undergo colonoscopy, stool-based tests like FIT and FIT-DNA can also detect cancer and, to a lesser extent, precancerous lesions.

The latest development in noninvasive colorectal cancer screening is the emergence of blood-based tests, the first of which was approved by the FDA in 2024.

 While they may be easier to access, May was careful to note key limitations to these tests, at least in their current formation, including their lack of sensitivity for precancerous lesions.

“If you're picking a blood based test, you're accepting that that test will likely miss a precancerous polyp and will mostly be looking for cancers, usually stage 2 and beyond,” May said. “Everyone has different preferences. I let patients decide what's best for them. To me, it's very important that they understand those nuances of the test.”

May goes on to emphasize that noninvasive tests are intended for average-risk individuals and not those with a family history or high-risk conditions such as inflammatory bowel disease or polyposis syndromes, additionally noting these patients should start screening earlier.

Editors’ note: May has relevant disclosures with Kimberly-Clark, Medtronic, Takeda, Freenome, Geneoscopy, and Exact Sciences.

Brooks A. FDA Approves First Blood Test for Primary Colorectal Cancer Screening. 

. July 29, 2024. Accessed April 21, 2025. 

https://www.hcplive.com/view/fda-approves-first-blood-test-primary-colorectal-cancer-screening

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May describes differences between colorectal cancer screening tests and which might be right for patients based on their preferences and values.

Advancements in Noninvasive Colorectal Cancer Screening, with Fola May, MD, PhD

With rates of colorectal cancer on the rise in younger adults and screening adherence rates lagging, the push for more accessible, less invasive options is at an all-time high. Today, patients have more choices than ever—from traditional colonoscopy to at-home stool tests and, most recently, blood-based screening.

“One of the biggest benefits we have in colorectal cancer screening is that we have multiple screening options,” Fola May, MD, PhD, an associate professor at the David Geffen School of Medicine and associate director of the UCLA Kaiser Permanente Center for Health Equity, explained to 

, describing the different noninvasive tests currently available to patients who are unable or unwilling to undergo colonoscopy.

In 2024, the FDA approved Exact Sciences’ Cologuard Plus test, the company’s next-generation multitarget stool DNA test, and Geneoscopy’s ColoSense, a noninvasive multi-target stool RNA colorectal cancer screening test, for adults ≥ 45 years of age at average risk of developing colorectal cancer.

The latest development in noninvasive colorectal cancer screening is the emergence of blood-based tests. In July 2024, the FDA approved Guardant Health’s Shield blood test for primary colorectal cancer screening in average risk adults ≥ 45 years of age.

“There’s only one of these that’s currently FDA approved, but there’s many of them that will be coming on the market soon,” May said.

Even with the availability of several noninvasive tests, colonoscopy continues to be viewed as the “gold standard” because it allows for real-time visualization of the colon and enables immediate removal of polyps during the procedure, offering both diagnostic and therapeutic benefits.

May notes that this process is slightly different for NITs, which involve a 2-step process: a positive result means the patient must then undergo a colonoscopy, something she says clinicians must communicate to their patients to ensure they know they are signing up for a colonoscopy if their noninvasive test comes back abnormal.

“I think many of us are very curious to see where [blood-based tests] fall,” May said. “Right now, I would say that the majority of physicians are still recommending that patients go ahead and pursue either a colonoscopy or one of these noninvasive test options I mentioned, either an FIT test, an FIT DNA test, or a CT colonography.”

However, she says blood-based tests are increasingly being used in patients who have historically been nonadherent to other screening options, as this provides them with an option they may view as easier or more convenient. As more data emerge and guidelines evolve, May notes the role of blood-based testing in colorectal cancer screening could expand.

Brooks A. FDA Approves Exact Sciences’ Cologuard Plus Test for Colorectal Cancer Screening. 

. October 4, 2024. Accessed April 21, 2025. 

https://www.hcplive.com/view/fda-approves-exact-sciences-cologuard-plus-test-for-colorectal-cancer-screening

Campbell P. FDA Approves ColoSense, a Noninvasive mt-sRNA Test, for Adults 45 or Older. 

https://www.hcplive.com/view/fda-approves-colosense-a-noninvasive-mt-srna-test-for-adults-45-or-older

May discusses currently available NITs for colorectal cancer screening, the continued importance of colonoscopy, and the emergence of blood-based tests.

Folasade (Fola) May, MD, PhD

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