New Colorectal Cancer Screening Options
ATLANTA — The American Cancer Society is introducing updated testing options for colorectal cancer screening, now including a blood test for the first time.
Colonoscopies remain the top method for detecting colorectal cancer, which can develop in the colon or rectum. This procedure, done under anesthesia, allows doctors to carefully inspect for early signs of the disease. However, some individuals prefer to avoid invasive procedures and may choose visual exams or stool-based tests, despite the discomfort some might feel about providing stool samples.
Unfortunately, many people skip screening entirely because they either can’t or won’t undergo these methods, even as instances of colorectal cancer increase in younger populations.
In response, the American Cancer Society has added blood testing as a screening alternative.
According to an updated guideline released recently, blood-based screenings are now recommended for adults 45 and older at average risk who have either declined or been unable to complete stool tests or visual exams.
The organization specifically endorses the Shield test from Guardant Health, which received FDA approval in 2024.
Additionally, the updated guideline includes new stool-based tests: an enhanced version of Cologuard, called Cologuard Plus, and a new FDA-approved option named ColoSense from Geneoscopy. Both tests are designed for at-home use where samples can be collected and sent to a lab for analysis, identifying molecular markers indicative of colorectal cancer.
Blood Test as an Alternative
Researchers behind the updates noted in a report in CA: A Cancer Journal for Clinicians that blood testing should only be suggested for individuals who opt out of more standard screening methods, such as colonoscopies or stool tests.
While blood tests are not the “first choice” due to their lower sensitivity in identifying precancerous polyps, Dr. William Dahut, chief scientific officer at the American Cancer Society, mentioned that they are a valid option for the right patients.
“Many people cannot or simply won’t undergo a colonoscopy, and the thought of providing stool samples is a dealbreaker for some,” Dahut remarked. “Having varied options could lead to more individuals getting screened, allowing for earlier cancer detection and potentially saving more lives.”
Early diagnosis significantly boosts survival rates, particularly if cancer is caught before symptoms manifest. More than 90% of individuals diagnosed with early-stage colorectal cancer are expected to survive for five years or more.
However, if cancer is discovered at a later stage, when it may have spread, treatment becomes more challenging and survival rates diminish, independent of the patient’s age.
Screening is also essential for reducing the risk of developing colorectal cancer, as nearly all cases begin with precancerous polyps that can be identified and removed during exams. If a stool test returns positive results, a follow-up colonoscopy is necessary for potential prevention, according to the American Cancer Society.
The updated guidelines are viewed as “forward thinking and realistic” by Dr. Ursina Teitelbaum, a professor of gastrointestinal oncology at the University of Pennsylvania, who was not part of the recommendation process.
Teitelbaum mentioned that while blood testing is imperfect due to its potential to miss early-stage cancers, it’s a move toward more inclusive screening options, particularly for younger demographics at risk.
Although the Shield test is currently the only recommended blood test, Dr. Scott Kopetz, a gastrointestinal medical oncologist at The University of Texas MD Anderson Cancer Center, suggests that more could follow.
“This is just the beginning for blood-based tests; we anticipate future developments will further enhance accessibility and performance,” Kopetz stated, adding that those willing to complete other recommended screenings should not rely on blood tests as substitutes.
