New strategy may enable accurate cancer monitoring from blood tests alone

The study, led by researchers from Weill Cornell Medicine and the New York Genome Center, in the US, showed that the method may be useful for monitoring disease status in patients following treatment.

The method, based on whole-genome sequencing of DNA, also represents an important step toward the goal of routine blood test-based screening for early cancer detection.

"We're now entering an era of low-cost DNA sequencing, and in this study, we took advantage of that to apply whole-genome sequencing techniques that in the past would have been considered wildly impractical," said Dr. Dan Landau, Professor of Medicine, at Weill Cornell Medicine.

In the study, published in the journal Nature Methods, the team focussed on an error-correcting method in a low-cost commercial sequencing platform.

The error-correction method makes use of the redundant information in natural two-stranded DNA.

The researchers found it enabled a very high "depth" of coverage -- a measure of the sequencing data quality -- allowing the team to detect extremely low concentrations of circulating tumour DNA. It also greatly improved the accuracy of the technique.

Blood-test-based "liquid biopsy" technology for early cancer detection and monitoring of cancer burden in patients could revolutionise cancer care, said the researchers.

The team demonstrated the potential of the high-sensitivity, low-error approach by using it to detect and assess very low cancer levels in patients with bladder cancer and melanoma from blood samples alone.

"We were able, for example, to see increases in circulating tumour DNA levels after treatment in patients with cancers that progressed or recurred and declines in those levels in patients whose cancers had full or partial responses," said Dr. Alexandre Cheng, a postdoctoral researcher.