# DETECT-A: a blood test plus PET-CT to screen 10,006 women with no symptoms

Source: https://onco.cc/terms/detect-a-study/  
OnCo record `detect-a-study` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

DETECT-A was the first prospective study to give a multi-cancer blood test to people with no symptoms and act on the result: 10,006 women had the test, positives were confirmed by PET-CT, and 26 cancers were found by the blood test, with about 1% of women sent for imaging that found nothing and 0.22% having an invasive procedure that was not needed.

## Summary

The Johns Hopkins and Geisinger study enrolled 10,006 women aged 65 to 75 with no history of cancer, tested their blood for mutations in cell-free DNA and for protein markers (the CancerSEEK assay), repeated positives on a second sample, and sent confirmed positives for whole-body PET-CT. The blood test detected 26 cancers, PET-CT localised most of them, and 15 of the 26 were confined to the organ or regional; with standard screening the study population also had 24 cancers found by mammography or colonoscopy. About 1% of participants had a false-positive result that led to imaging and 0.22% had a futile invasive diagnostic procedure; 99% of those tested were not led to an unnecessary procedure, and the authors reported that the test did not reduce uptake of standard screening (Lennon 2020). For pancreatic cancer the study is the proof that a blood-first pathway is workable at population scale, and the reminder that sensitivity for early-stage disease, not specificity or safety, is the limiting factor: the methylation test that followed reads 16.8% sensitivity at stage I across cancers (the CCGA term), and CA 19-9 rises only about two years before diagnosis.

## Fields

- Kind: Term
- Last checked: 2026-09-24
- Also known as: DETECT-A; Detecting cancers Earlier Through Elective mutation-based blood Collection and Testing; CancerSEEK prospective study
- Tags: pancreatic-molecular

## Sources

- Lennon et al., Science 2020: DETECT-A, blood testing plus PET-CT in 10,006 women: https://doi.org/10.1126/science.abb9601
- Cohen et al., Science 2018: CancerSEEK in 1,005 patients with eight cancer types: https://doi.org/10.1126/science.aar3247

## Connected records

- cancers: [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/)
- technologies: [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [Multi-cancer early detection (MCED)](https://onco.cc/technologies/mced/), [PET/CT](https://onco.cc/technologies/pet-ct/)
- institutions: [Johns Hopkins Hospital / Sidney Kimmel Comprehensive Cancer Center](https://onco.cc/institutions/johns-hopkins/)
- terms: [CCGA: the Circulating Cell-free Genome Atlas behind the Galleri methylation test](https://onco.cc/terms/ccga-study/), [Cell-free DNA (cfDNA)](https://onco.cc/terms/cfdna/), [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Positive predictive value (PPV)](https://onco.cc/terms/ppv/), [Stage shift](https://onco.cc/terms/stage-shift/)
- people: [Bert Vogelstein](https://onco.cc/people/bert-vogelstein/), [Nickolas Papadopoulos](https://onco.cc/people/nickolas-papadopoulos/)
- key papers: [DETECT-A: a blood test plus PET-CT found treatable cancers in 10,000 women with no symptoms](https://onco.cc/key-papers/paper-detect-a-science-2020/), [Detection and localization of surgically resectable cancers with a multi-analyte blood test](https://onco.cc/key-papers/paper-cohen-cancerseek-multi-analyte-blood-test-science-2018/)

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