As Korea’s colorectal cancer screening system faces the dual challenge of improving early detection accuracy while expanding accessibility, attention is turning to whether Shield (SHIELD), a blood-based colorectal cancer screening test imported and distributed by Dow Biomedica, could complement the limitations of the current fecal occult blood test (FOBT)-centered screening structure.

Moving beyond approaches that rely on the presence of bleeding, molecular-level analysis may broaden both the accuracy of early detection and the range of screening options available to individuals.

Colorectal cancer ranks among the most common cancers in Korea in both incidence and mortality. Although it is generally considered highly treatable when detected early due to its relatively slow progression, a significant number of cases continue to be diagnosed at advanced stages in real-world clinical settings.

The fecal occult blood test currently used in the national health screening program offers convenience and cost efficiency by detecting blood in stool samples. However, concerns have been raised about its potential to miss early-stage cancers or precancerous adenomas that do not present with bleeding.

Against this backdrop, Shield is a molecular diagnostic test that simultaneously analyzes three key biomarkers in blood: colorectal cancer-related DNA mutations, methylation patterns, and DNA fragmentation. Rather than relying on bleeding, the test is designed to detect molecular alterations that occur during the process of tumor development.

By leveraging molecular signals that may not be detectable through conventional immunochemical tests, the approach aims to enhance sensitivity. The company notes that the test may provide a non-invasive screening option particularly for individuals reluctant to undergo repeated colonoscopy or those who may fall into screening blind spots despite being at elevated risk.

Dow Biomedica has introduced and supplied advanced in vitro and molecular diagnostic technologies to the Korean market. Through Shield, the company seeks to diversify screening options in the field of early colorectal cancer detection.

The company emphasizes that the test is not intended to replace colonoscopy but rather to serve as a complementary screening tool, offering an initial step for individuals who face barriers to conventional screening methods.

The NCCN 2025 Guidelines recommend Shield for colorectal cancer screening. Notably, the test received U.S. Food and Drug Administration (FDA) Premarket Approval (PMA) supported by large-scale clinical data involving more than 20,000 participants — an uncommon achievement for a screening assay. In several countries, stepwise strategies combining molecular diagnostic stool tests and colonoscopy are gradually gaining traction.

Experts point out that improving colorectal cancer screening outcomes requires not merely comparing individual test modalities, but implementing personalized strategies that consider age, family history, lifestyle factors, and underlying medical conditions.

While molecular diagnostics hold significant potential to enhance early detection, discussions must also address cost considerations, healthcare system sustainability, and consensus on appropriate clinical utilization.

As colorectal cancer screening evolves from a routine procedural check toward more individualized risk assessment, blood-based screening tests such as Shield are being viewed as one option that may help address gaps in the current system.

At the same time, successful implementation in real-world clinical practice will require sufficient education and communication for both healthcare professionals and individuals undergoing screening. Clear explanations of the test principles, result interpretation, and the possibility of false positives or false negatives are essential to prevent unnecessary anxiety or over-screening.

An industry expert noted, “Achieving the goal of early colorectal cancer detection will require not only the introduction of new technologies, but also the establishment of clinical guidelines and educational frameworks. Institutional discussions will therefore become increasingly important.”