A blood test can detect DNA traces of a tumour several months before diagnosis, reports Dagens Medicin. A new study included almost 400 patients at seven Swedish hospitals who were treated for colon and rectal cancer. Blood samples for tumour DNA were taken at various intervals up to two years after treatment, which usually included surgery.
A positive test for tumour DNA was linked to a 32- and 72-fold increased risk of recurrence detected on X-ray for colon and rectal cancer, respectively.
According to Anna Martling, one of the researchers behind the study, research is underway in which decisions are made based on the blood test, for example by giving or not giving chemotherapy.
"There is much evidence that within a couple of years we will start using the method to individualise treatment," she tells the newspaper.
The researchers used a sensitive test that allows them to detect relapses early.
The sensitive test also allowed us to detect very unusual recurrences early after surgery for stage 1 cancer, both in colon and rectal cancer, where the tumour only grows superficially in the intestinal wall, says Anna Martling.
The results of the study are presented at the ongoing Surgeons' Week in Malmö.
