A newly developed blood test, known as cfDNA test, has shown remarkable accuracy in detecting colorectal cancer in the majority of cases. Colorectal cancer screening, while crucial, can be inconvenient, making adherence to screening guidelines challenging. Experts are optimistic that this novel test could bridge this gap and encourage more adults to undergo regular screening for colorectal cancer.

The test, which involves a simple blood draw, has demonstrated an impressive 83% detection rate in clinical trial data. This detection rate is comparable to that of the widely used at-home screening test, the fecal immunochemical (FIT) test, which is accurate in approximately eight out of 10 cases. While colonoscopies remain the gold standard for colorectal cancer detection, they require more time, scheduling, and preparation.

Experts believe that the combination of accuracy and accessibility offered by the cfDNA test could revolutionize colorectal cancer screening efforts. Dr. Christopher Chen, Assistant Professor of Oncology at the Stanford Cancer Institute, describes the potential of this test as “very, very exciting,” suggesting that it could reshape the landscape of early colon cancer detection. Dr. Ben Park, Director of the Vanderbilt-Ingram Cancer Center at Vanderbilt University, emphasizes the importance of clinical validation and acknowledges the test’s imperfections but sees it as a significant step forward.

Although further research and validation are needed, the cfDNA test holds promise in making colorectal cancer screening more convenient and effective.

Jump to section

83% Accuracy | Low Cancer Screening Rates | Conclusion

Accurate in 83% of cases

The findings of the study stem from the extensive ECLIPSE trial, involving over 8,000 participants aged 45 to 84. These individuals, deemed at average risk for colorectal cancer, were already undergoing routine screening for the disease.

In this trial, the effectiveness of Guardant Health’s Shield blood test was compared to colonoscopy. Out of the 65 participants diagnosed with colorectal cancer via colonoscopy, the cfDNA test correctly identified cancer in 54 individuals, marking an 83.1% success rate.

However, it’s important to note that the test does not screen for precancerous lesions or polyps, which can lead to cancer. For precancerous lesions, the test detected only about 13% of cases.

Dr. Christopher Chen emphasized that while the test is valuable for detecting cancer, it does not prevent cancer, highlighting a crucial distinction.

Cell-free DNA blood-based tests function by detecting tiny DNA fragments released by tumors or cancerous tissue. Dr. Ben Park noted that these tests represent a pioneering approach, combining mutations and epigenetic marks for cancer detection.

Despite its potential, the challenge lies in effectively identifying these minuscule DNA fragments. Dr. Park explained that while cells in our body release such DNA for decades, technology limitations hindered their detection until now.

Only two-thirds of Americans get cancer screening

Colorectal cancer ranks as the second-leading cause of all cancer-related deaths. Despite its severity, many adults neglect recommended screenings, with less than 60% of those aged 45 to 75 undergoing screening, missing the chance to prevent an estimated 35,000 deaths annually due to colorectal cancer.

Dr. Robert Smith, Senior Vice President of Early Cancer Detection Science at the American Cancer Society, highlighted the challenge of persuading healthy individuals to undergo screening. The inconvenience of colonoscopies often leads to avoidance.

The appeal of the cfDNA blood test lies in its potential to increase screening rates, even if it’s less accurate. Dr. Christopher Chen emphasized the importance of wider adoption, considering that a test not received by patients is ineffective.

Dr. Smith questioned whether prioritizing accuracy over accessibility is practical, given the reluctance of many to undergo testing. He stressed the importance of making screening simple and appealing to encourage compliance.

While acknowledging the preference for accuracy, Dr. Smith emphasized the significance of a test that a substantial portion of the population is willing to undergo.

The bottom line

A breakthrough blood test can detect colorectal cancer in roughly 83% of cases, matching the accuracy of certain at-home screening tests.

Despite its lethal nature, colorectal cancer screening rates remain low among adults.

Experts see the new test as a potential solution to improve accessibility and encourage regular screening among adults.

Jump to section

83% Accuracy | Low Cancer Screening Rates | Conclusion