A SIMPLE blood test could give immediate feedback on the success of cancer treatments — and detect relapses in “cured” patients — thanks to a world-first breakthrough by a Melbourne scientist.

Dr Sarah-Jane Dawson, from the Peter MacCallum Cancer Centre, has proven that blood samples could be just as effective as tissue biopsies in analysing the behaviour of some cancers.

The discovery could fast-track cancer treatment, giving doctors advanced warning when their treatments are not working — and time to change their tactics.

The research, published today in the Nature Communications journal, showed how “circulating DNA” could be accurately detected and measured in the bloodstream.

Dr Dawson said everybody had “small fragments of DNA” in their bloodstream: “But cancer patients actually have much higher levels ... and that’s because the cancer itself can shed small amounts of this DNA into the bloodstream.”

Until recently, accurately detecting and measuring the amounts of this DNA in blood plasma had been like “looking for a needle in a haystack”, she said.

But now Dr Dawson and counterparts from the University of Cambridge have taken this breakthrough a critical step further, proving “what circulating DNA can tell us about the cancer itself”.

The team found that this type of blood test, dubbed a “liquid biopsy”, was just as informative as the much more invasive tissue biopsy (where a sample from the tumour itself is taken).

“We’ve found that it very accurately represents the genetic changes that are present in the underlying cancer,” said Dr Dawson, head of Peter MacCallum’s molecular biomarkers and translational genomics laboratory.

“We think we’ll be able to use this information to understand how well patients are responding to therapy and, if they’re not, try and predict what therapies might be better for that particular individual.

“From the patient's perspective, it doesn’t mean anything more than a blood test.”

Dr Dawson hopes the blood tests would be available for patients with a range of cancers within five years.

She said they would “complement, rather than replace” tissue biopsies, and would be used on patients in varying stages of the disease — as well as for monitoring patients “at risk of relapse”.

Dr Dawson’s research was based on the extensive analysis of blood and tissue samples from a 42-year-old breast cancer patient.

Dr Dawson said she was currently recruiting patients with advanced metastatic breast cancer to contribute blood samples to further her research.

Story source: Herald Sun