A small study — deemed “more encouraging than definitive” by commentators — shows that circulating DNA from breast tumors can be used to track progression in metastatic breast cancer.

Researchers monitored the tumor burden of 30 women with metastatic disease with use of radiographic imaging plus assays of circulating tumor DNA, circulating tumor cells, and the cancer antigen CA 15-3.

Circulating tumor DNA was found in 29 of the 30 women with identifiable mutations. The sensitivity of the assays for CA 15-3 (78%) and circulating tumor cells (87%) was lower. Increasing levels of circulating DNA and tumor cells both correlated with inferior survival.

Writing in the New England Journal of Medicine, editorialists say the work “provides proof of the concept that circulating tumor DNA represents a sensitive biomarker of tumor burden” — and call for further studies.

Source: NEJM