How Close Are We to Early Cancer Detection With a Single Blood Test?

Can a Single Blood Test Detect 13 Cancer Types?

Promising Data and Cautious Realities of a New MCED Test

Cancer remains one of the world's greatest health threats. Some cancers, particularly pancreatic, ovarian, and gastric cancer, cause no early symptoms and are often diagnosed late. Early detection can greatly improve treatment success. Developing ways to detect cancer before symptoms appear has therefore become a medical priority.

One technology developed toward this goal in recent years is multi-cancer early detection (MCED) testing . By analyzing circulating cell-free tumor DNA (cfDNA) in a single tube of blood, these tests aim to identify cancer and even its organ of origin.

What Does the New Nature Medicine Study Tell Us?

In June 2025, Nature Medicine published results of an MCED test developed by the China-based biotechnology company Geneseeq Technology Inc. . The test can detect 13 different cancer types from a single blood sample:

🔹 Breast
🔹 Cervical
🔹 Colon and rectal
🔹 Endometrial
🔹 Esophageal
🔹 Gastric
🔹 Liver
🔹 Lung
🔹 Ovarian
🔹 Pancreatic
🔹 Prostate
🔹 Biliary tract
🔹 Lymphoma

These cancers account for 66.6% of all new cases and 74% of cancer deaths worldwide.

How Does the Test Work?

It assesses the genetic and structural features of cfDNA . It evaluates not only mutations but also:

• Copy number variations (CNV)
• Fragment-length distribution
• Nucleosome footprints
• cfDNA methylation patterns

. An advanced AI algorithm analyzes these biological signatures together, enabling it to answer "Is Cancer Present?" and predict its tissue of origin .

How Strong Are the Scientific Findings?

The study had three stages:

1. Model training: Blood samples from 6553 people were analyzed (3076 with cancer, 3477 healthy).
2. Independent validation: A new group of 1465 people was tested.
3. Real-world screening: 3724 asymptomatic individuals were tested.

🔬 Most notable results:

• Overall sensitivity: 87.4%
• Overall specificity: 97.8%
• Stage I sensitivity: 79.3%
• Stage II: 86.9%
• Stage IV: 97.1%
• Pancreatic cancer: 76.9%
• Ovarian cancer: 90.5%
• Liver and biliary tract cancers: 100%
• Breast cancer sensitivity: 63.8%

These results show that some cancers can be detected with high accuracy even at early stages.

But Is It Really That Simple?

Despite its promise, the test has limitations. Most importantly, how often does a positive result actually mean cancer?

👉 Positive Predictive Value (PPV): 25%

This means that among 4 people with positive results, only 1 actually has cancer. The other 3 may face unnecessary anxiety, follow-up imaging, or biopsy.

In the referenced 2023 PATHFINDER study, PPV was 38%. This new test therefore produces somewhat more false positives .

How Did It Perform in Population Screening?

When used in asymptomatic individuals, the test:

• Detected 23 of 43 people with cancer
• Sensitivity for the 13 target cancers: 62.1%
• Specificity: 98.1%
• False-positive rate: Only 0.54% (20/3724 people)

Interestingly, the test identified cancers in 8 people that physical examination had not detected, highlighting MCED's potential to find hidden cancers .

How Much Do MCED-Detected Cancers Overlap With Those Found by Conventional Screening?

Are there cases missed by conventional screening but detected by MCED?

• MCED + guideline-recommended screening: 11 of 18 cases were detected simultaneously
• Outside conventional screening: 4 of 8 cases overlapped with MCED
• MCED flagged 2 cancers missed by conventional screening: one year in advance
• Of 15 cases identified through clinical suspicion, 8: were detected early by MCED

Conclusion: Promising, but Too Early for Routine Clinical Use

Advanced bioinformatics and cfDNA analysis allow this MCED test to detect 13 cancer types early. It is particularly exciting for cancers without screening programs, such as pancreatic and ovarian cancer .

However, questions remain before widespread use:

• What will cost and accessibility be like?
• How can false positives be reduced?
• How will psychological effects be managed?

For these reasons, this test should be considered a complement to conventional screening rather than a replacement .

Final Thoughts

Detecting dozens of cancers with a single blood test is no longer science fiction, but becoming a clinical reality will take more time and careful progress. Science is advancing, and we continue to follow it closely.