False Signals From New Cancer Tests Cause Worry and Harm
A new kind of test aims to find many types of cancer early by looking at a blood sample. These tests, called Multi-Cancer Early Detection (MCED) tests, have shown promise. However, a large study called DETECT-A has brought important questions about their use. The study found that when these tests show a positive sign for cancer, it doesn't always mean cancer is present. This can lead to people having further tests and even medical procedures that are not needed. These extra steps can be upsetting, costly, and sometimes harmful.
Understanding MCED Tests and the DETECT-A Study
Multi-Cancer Early Detection (MCED) tests are a new area in cancer screening. Unlike tests for just one type of cancer, these aim to detect signals from many different cancers at once.
How they work: MCED tests often look for pieces of DNA or other signals released by cancer cells into the blood. This is sometimes called a "liquid biopsy."
The Goal: The main aim is to find cancer earlier, when it might be easier to treat.
The DETECT-A Study: This was a large, planned study to see how these tests perform in real-world situations. It is described as the "First Large, Prospective, Interventional MCED Study."
The study's findings highlight a key challenge: a positive result from an MCED test is not a diagnosis.
Read More: Eric Dane, Actor, Dies at 53 After ALS Battle in February 2026
"For example, a positive MCD signal alone is not diagnostic of cancer."
This means that even if the test says "cancer likely," more checks are needed to confirm if cancer is truly there. The study's results are important because they look at what happens after a false-positive signal.
Evidence: When Tests Signal Cancer, But It's Not There
The DETECT-A study specifically looked at what happens when an MCED test gives a "false-positive" result – meaning it signals cancer, but cancer is not found.
Outcomes from False Positives: The study investigated the health results for people who received a false-positive signal from an MCED test. This means it followed individuals who were told they might have cancer based on the test, but further checks found no cancer.
Interventional Study: The "Interventional" part of the study's name suggests that people in the study underwent additional medical actions or procedures based on the test results.
The core finding is that false-positive signals from MCED tests lead to follow-up actions that may not be medically necessary.
What Happens After a False Signal?
When an MCED test shows a positive result, people often undergo a series of further medical investigations to determine if cancer is present.
Diagnostic Process: This can involve imaging tests like CT scans or MRIs, and invasive procedures like biopsies.
Patient Impact: Receiving a false-positive result can cause significant anxiety and stress.
Risks of Procedures: Biopsies and other diagnostic procedures carry their own risks, including infection, bleeding, and pain.
The DETECT-A study's results shed light on the consequences of these follow-up actions when the initial MCED test was wrong.
Challenges in Defining "Early Cancer"
Part of the complexity with early cancer detection lies in defining what "early stage" truly means.
Read More: New Wegovy Pill for Weight Loss Approved by FDA in Late 2025
Spectrum of Disease: Early signs of cancer can range from changes in cells that might become cancer (premalignant) to very small cancers that haven't spread (presymptomatic stage III cancer).
Test Sensitivity: MCED tests are designed to pick up signals from these various stages, but the exact point at which a signal is considered "cancer" can be unclear.
The definitions of what counts as "early stage cancer" can differ, adding a layer of difficulty to interpreting MCED test results.
Expert Views on MCED Tests
Experts in the field recognize both the potential and the current limitations of MCED tests.
"MCED tests are not simple blood tests."
This statement from a translational science review underscores that these tests are complex and their results require careful interpretation.
Translational Science: This field focuses on moving scientific discoveries from the lab to patient care. MCED tests are a key area of focus within translational science.
Need for More Data: While promising, more research is needed to understand the full impact of these tests on patient outcomes and healthcare systems.
Conclusion: Balancing Promise with Precaution
The DETECT-A study's findings are a significant step in understanding the real-world performance of MCED tests. While these tests hold the promise of detecting cancer earlier, the study highlights that false-positive signals can lead to unnecessary anxiety and medical interventions.
Implications for Use: The results suggest a need for careful consideration of how MCED test results are communicated to patients and how follow-up diagnostic pathways are managed.
Further Research: Ongoing studies are crucial to refine these tests, improve their accuracy, and determine which populations might benefit most from their use. The balance between early detection and the risks of false positives needs careful management.
Sources Used:
Outcomes Following a False-Positive Multi-Cancer Early Detection Test: Results from DETECT-A, the First Large, Prospective, Interventional MCED Study
Context: This is the primary source detailing the results of the DETECT-A study concerning false-positive MCED test results.
Cancer screening with multicancer detection tests: A translational science review
Link: https://acsjournals.onlinelibrary.wiley.com/doi/full/10.3322/caac.21833
Context: This review provides a broader scientific perspective on MCED tests, their complexity, and the interpretation of their signals.
Early Cancer Detection: Challenges and Opportunities
Link: https://link.springer.com/chapter/10.1007/978-3-031-22903-924
Context: This source touches upon the scientific efforts and complexities involved in developing multi-cancer screening methods using liquid biopsies.
