Early detection of cancer can help in administrating effective treatment and improve lifespan. We may be a step closer to this outcome with a team of American scientists now developing a blood test that can detect cancer at a very early stage. Published in the journal Annals of Oncology, the test claims to treat more than 50 types of cancers and identify the tissue where the cancers originated. 
To develop the test, the scientists picked 6689 participants. Of them, 2482 were cancer patients with more than 50 types of cancers between them. These participants were divided into validation and training sets. The team then developed blood tests that could be used for cancer detection and tissue of origin (TOO) localization. The blood test worked by analyzing the chemical changes in the DNA that are caused by tumor growth.
The researchers showed that the test has a 0.7% false-positive rate, which is significantly lower than many cancer detection tests available today. When it came to TOO, the test was able to predict the origins in 96 percent samples with an impressive accuracy rate of 93 percent. Thus, the blood test can detect cancer even before clinical symptoms appear. The researchers pointed out that this test could be a powerful tool in cancer screening and prevention.