A simple blood test called 'CancerSEEK' has been developed at Johns Hopkins University in Baltimore and could detect cancer before an injured person feels sick. This could catch tumors in stage1 when chances are best to cure it.
Why is a test for cancer detection so helpful?
Many cancer therapies are invasive, expensive and cancer patients have to bear a lot of pain a long time (depending on stage). A minimal-invasive test that detects the tumor before it spreads would save unnecessary time and pain and could reduce cancer deaths in the long term.
How does it work?
In our blood are DNA pieces of different tumor types. The assay - a type of 'liquid biopsy' - uses biomarker proteins that bind specific on different kinds of cancer in the blood. The researchers marked 8 different proteins that bind specific on each tumor DNA and the signal given can be detected. The test is not perfect, because when DNA in mutates, the biomarker can't bind; that's why there could be false negative results.
Until now the test yielded a positive result in about 70% of cases with 8 common cancer types on about 1000 people whose tumors had not yet spread. Some types of cancer can be detected better than others, but it is so specific that a false positive detection rarely happened (1% false positive rate).
There's a possibility that the test can be used as a screening tool, testing many people in a short time for about 500$. A 5-year study with blood samples of 50,000 women (have never had cancer) has already begun in Pennsylvania funded by the private Marcus Foundation.
Source:
http://www.sciencemag.org/news/2018/01/liquid-biopsy-promises-early-detection-cancer
https://www.hopkinsmedicine.org/news/media/releases/single_blood_test_screens_for_eight_cancer_types