Detection Of Early Stage Cancers Using Circulating Tumor DNA.

One "holy grail" of cancer diagnostics is the development of a non-invasive (e.g., blood) test that can detect early stage cancers.  Some progress has been made; from the abstract

Evaluation of 200 patients with colorectal, breast, lung, or ovarian cancer detected somatic mutations in the plasma of 71, 59, 59, and 68%, respectively, of patients with stage I or II disease…These analyses provide a broadly applicable approach for noninvasive detection of early-stage tumors that may be useful for screening and management of patients with cancer.

Therefore, tumor DNA. and its diagnostic mutations, can be found in the plasma of a majority of patients with early stage cancers.  That is good news, and we await further refinement of this approach.