Stanford Study Reveals Blood Tests for Colon Cancer Fall Short of Colonoscopy Effectiveness

Stanford researchers discovered that new blood exams for colorectal most cancers screening aren’t as efficient as colonoscopies or stool exams.

New blood exams for colorectal most cancers screening could appear to be an interesting various to a typical colonoscopy. Unlike the normal process, which requires bowel preparation and may be invasive, these exams want solely a easy blood draw. But are they as efficient?

Research from Stanford Medicine means that whereas these blood exams may fit properly for people who keep away from different screening strategies, they fall brief when in comparison with colonoscopies or stool-based exams. If too many individuals select blood exams over these established strategies, colorectal most cancers dying charges may rise. The examine discovered that colonoscopies and stool-based exams are considerably higher at detecting early cancers and precancerous polyps, providing a higher long-term influence on most cancers prevention and survival.

“The first generation of blood tests are a really exciting development in the colorectal cancer screening paradigm,” stated Uri Ladabaum, MD, a professor of gastroenterology and the primary writer of the paper, to be revealed right now (October 28) in Annals of Internal Medicine. “But for now, if you’re willing and able to do a colonoscopy or stool-based test, don’t switch to a blood test.”

Ladabaum additionally identified that, at a inhabitants degree, the blood exams shall be efficient at lowering colorectal most cancers deaths provided that individuals who reliably take the take a look at each three years subsequently conform to obtain a follow-up colonoscopy if the blood take a look at returns a optimistic consequence.

Current Screening Recommendations and Practices

With the present screening charges within the inhabitants, about 4% of all American adults shall be identified with colorectal most cancers sooner or later of their lifetimes. Regular screening may also help determine early cancers and precancerous polyps and scale back a person’s threat of creating, and dying, from colorectal most cancers. The U.S. Preventive Services Task Force recommends that every one adults between the ages of 45 and 75 be screened for colorectal most cancers.

For a long time, screening has required both a once-a-decade colonoscopy, by which a skinny versatile tube with a digicam is used to look inside a person’s giant gut, or a stool take a look at each one to 3 years. During a colonoscopy, clinicians cannot solely detect colorectal cancers, but in addition take away precancerous polyps which might become cancers.

“This makes colonoscopy a unique cancer screening method because you also have the possibility of cancer prevention,” Ladabaum stated. “Despite that, there are many people who are not getting screened at all, or who are not getting screened as often as they should.”

Data present that about 1 in 3 American adults within the beneficial age vary have by no means been screened for colorectal most cancers, so clinicians are hoping that new strategies may encourage them to endure screening.

The Rise of New Screening Technologies

In 2014, the U.S. Food and Drug Administration accepted the primary multi-target stool-based colorectal screening take a look at, by which stool collected at house by a affected person each one to 3 years is analyzed for the presence of small quantities of blood or most cancers DNA. This summer season, the FDA accepted a brand new methodology that appears for bits of most cancers DNA circulating in a person’s bloodstream. These first-generation blood-based exams don’t diagnose precancerous polyps properly.

“This is a time of intense interest in the colorectal cancer screening field. The paradigm in screening could be changing,” Ladabaum stated. “But conducting a randomized controlled trial directly comparing these emerging screening tests over the long term is unfeasible, which leaves patients in a difficult place when they’re weighing their options.”

Comparative Study Results and Cost-Effectiveness

Ladabaum and his collaborators collected beforehand revealed knowledge on six commercially out there or in-development blood- and stool-based screening exams in addition to the gold-standard colonoscopy. Using this knowledge, they modeled the relative charge of colorectal most cancers and deaths amongst 100,000 average-risk individuals who used every screening method.

Among 100,000 individuals who obtain a colonoscopy each 10 years, 1,543 would develop colorectal most cancers and 672 would die from the illness, they decided. For stool-based exams each one to 3 years (relying on take a look at) the incidence of colorectal most cancers ranged from 2,181 to 2,498 circumstances per 100,000 folks, and deaths ranged from 904 to 1,025. For the brand new blood exams, beneficial to be carried out each three years, the circumstances ranged from 4,310 to 4,365, and deaths ranged from 1,604 to 1,679 — about two and a half occasions as many deaths as within the colonoscopy group.

Among those that obtain no screening, 7,470 would develop the most cancers, and 3,624 would die from it.

Moreover, when the group regarded on the prices related to every take a look at, they discovered that colonoscopies and stool-based exams had been more cost effective than blood-based exams.

“The blood tests are certainly much better than nothing, but you’ll worsen the population outcomes and raise health care costs if you see people switching from colonoscopies to first-generation blood tests,” Ladabaum stated.

Potential Impact of Patient Choices on Screening Outcomes

When Ladabaum’s group modeled the impact of affected person decisions on population-wide colorectal most cancers charges, they discovered most individuals persevering with to display with colonoscopy or stool-based exams because the best-case state of affairs. Blood exams needs to be used solely by individuals who wouldn’t in any other case be screened.

The analysis group stated they want real-world knowledge on affected person decisions about colorectal most cancers screening to higher refine their mannequin on how the blood exams will have an effect on most cancers charges.

“It remains to be seen who will really use the blood tests,” Ladabaum stated. “Will it be people who have never been screened using any other method? And will they be willing to get a follow-up colonoscopy if indicated?”

He additionally stated blood exams may enhance, and the present outcomes would then not maintain true for future generations of the exams.

Conclusion and Future Outlook

For now, the researchers hope that sufferers — and clinicians — stick to the best screening strategies at the moment out there. 

“Ideally, we want as many people as possible to get screened for colorectal cancer, and that’s likely going to mean a combination of different tests being used across the population,” Ladabaum stated.

Reference: “Projected Impact and Cost-Effectiveness of Novel Molecular Blood-Based or Stool-Based Screening Tests for Colorectal Cancer” by Uri Ladabaum, MD, MS, Ajitha Mannalithara, PhD, Robert E. Schoen, MD, MPH, Jason A. Dominitz, MD, MHS and David Lieberman, MD, 29 October 2024, Annals of Internal Medicine.
DOI: 10.7326/ANNALS-24-00910

Scientists from the University of Pittsburgh, the University of Washington, and the Oregon Health and Sciences University contributed to the analysis.

Funding for this analysis was offered by the Gorrindo Family Fund.