You could soon know if cancer treatment works ahead of time

In an ambitious new study that would make Dr. Strange proud, scientists from The Institute of Cancer Research, London, aim to harness the power of fortune-telling to treat breast cancer.

Their research, if proven out at scale, would allow doctors to tell whether drugs to treat breast cancer—the second-most commonly diagnosed cancer in the world—will work for each individual patient before treatment even starts.

How they did it: The UK scientists developed a liquid biopsy that analyzes circulating tumor DNA, or ctDNA, in a patient’s bloodstream, a molecule that’s released by cancer cells in varying levels.

• They recorded ctDNA levels in blood samples from 167 patients with advanced breast cancer, both before treatment began and four weeks in.
• Then, scientists compared those levels with how well patients responded to treatment, and how long their cancer stayed under control.

The results were striking

Patients with low ctDNA levels at the start of treatment tended to respond better to therapy. The same pattern showed up at the four week mark. “Our study shows that a simple blood test measuring circulating tumour DNA can provide an early prediction of whether a patients’ breast cancer will respond to treatment,” said lead author Dr Iseult Browne.

Why it’s a big deal: If doctors can see early on that a treatment is unlikely to work, they could switch strategies sooner and embrace alternative options like targeted therapy or a clinical trial for a novel drug, rather than losing valuable time on treatments that likely won’t help (and could carry some nasty side effects).

Looking ahead…Clinical trials are now underway to test whether changing treatment plans based on these early blood test results will improve patient outcomes in the long run.