[stig]

I’m thinking that early cancer is localized, so there really would be nothing to detect elsewhere in the body or in the blood. But a cancer that has begun to metastasize would be shedding cells, and some of them could make it into the blood.

If your using the test to detect early cancer then there would be no metastatic disease. The test would tell you the type of tissue the cancer is located in: Lung, Liver, Intestine. It would not give you an exact (x,y,z) coordinate/

If you use the test in metastatic cancer it would tell you what tissue the primary tumor came from.

[exDemMom]

If your using the test to detect early cancer then there would be no metastatic disease.

That's one of the details I would like to know more about. If there is no metastatic disease, then how is there detectable DNA from cancer cells in the blood?