London - A smart blood test detects the spread of breast cancer almost a year earlier than scans, research shows.
It analyses DNA in the blood to show with high accuracy whether cancer will recur after treatment.
A study of 101 women in five UK hospitals showed doctors could see how breast cancer was evolving 10.7 months before tumours appeared on scans. Although at an early stage, the findings pave the way for large clinical trials.
It is one of the first in a battery of "liquid biopsies" experts believe will revolutionise cancer treatment.
The sensitive test, which works by detecting tiny cells that are shed by a tumour as it grows, allows doctors to determine whether cancer will spread through the body. Existing techniques, which involve biopsies and scans, can be done only once the tumour has already spread.