London: Scientists have devised a new simple blood test that can clearly show whether treatments to reduce tumours is working, a breakthrough which they say could soon revolutionise cancer care.
British researchers, who developed the new blood test, said can closely monitor the progress of tumours without the need for surgery or scans.
In a world first, they used the blood analysis to detect deadly mutations in 20 of 38 patients studied with breast and ovarian cancer. They even managed to build up a picture of how one woman`s breast cancer responded to different treatments over 16 months.
The new test, expected to be available to patients within five years, uses sequencing -- a technique to read genetic code -- to look for tiny pieces of DNA that cancer tumours shed into the bloodstream and are not picked up by current screening methods, the Daily Mail reported.
This could alert doctors when a treatment is not working, allowing them to try alternatives, as well as potentially sparing the patient unnecessary side effects. Currently cancer patients often need to have tissue samples surgically removed for analysis.
In the study, published in journal Science Translational Medicine, the researchers took blood samples from women either before, during or after chemotherapy at Addenbrooke`s Hospital in Cambridge.
Dr Nitzan Rosenfeld, who led the study at the Cancer Research UK Cambridge Research Institute, said: "This type of blood test has the potential to revolutionise the way we diagnose and treat cancer. The great advantage is that it can be used to identify cancer mutations without surgery or a biopsy, making it safer and cheaper."
DNA sequencing is widely used, but Rosenfeld`s team found a way to home in on key genes known to be "cancer hot spots" and analyse them in detail.
This is the first time entire genes have been analysed from a blood test, which enabled the researchers to examine 20,000 possible mutations in six cancer-related genes.
Using a blood sample from a 56-year-old woman with breast cancer, the researchers were able to see in retrospect that the first type of treatment she was given had not worked.
Dr Rosenfeld said: "We could see in a blood test what the doctors could only see using extensive imaging. It suggests that if we had looked at a different time point, we may have been able to spot it earlier.
"Doctors could try different types of chemotherapy or refer patients to a specific clinical trial. It broadens the scope for more personalised medicine."
He said more tests would be needed to see which cancers could be detected by this process, but there was no reason why it would not work if scientists targeted the right gene.
Co-author Dr James Brenton said: "I think these results are very exciting because work from us and others really says now that blood could be an important way of measuring response and finding these mutations.
"It offers us an opportunity to follow the disease in real time as it changes, helping us to respond and change the treatments we use."