blood test that detects cancer?

[SuzEQ]

My understanding of testing for CTCs is that it is not as expensive or risky for the patient as traditional types of surveillance such as CT and PET. There is no radiation, no dye, no machines for patients to sit in (MRI), simply drawing blood. Even better, this test can be used to detect response to a new chemo in Stage IV patients within appr. 3 weeks of starting therapy. If the CTCs go down with a new treatment, great since the therapy is working, if up, change treatments. Quick, easy for the patient, and non-invasive. I'm curious if they can use this on an annual basis to be sure that those with NED are truly NED and if not, can then provide a workup. This seems a little better than tumor markers but maybe not as routinely accepted at this point or perhaps it is simply not accurate in this group. If anyone has discussed this with their oncologists, I would be interested to see what they say.