Scientists have developed a new technique to detect and monitor cancer that does not require invasive surgery and is thought to be up to 10 times more sensitive than traditional methods.
The process involves using a “personalised” genetic testing approach, which allows clinicians to look for genetic mutations of tumour DNA (ctDNA) floating in the bloodstream that are specific to the patient.
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According to the researchers, the test is sensitive enough to detect one mutant DNA molecule among a million pieces of DNA, making it far more sensitive than traditional methods.
They believe this new method, detailed in the journal Science Translational Medicine, would allow clinicians to not only spot signs of the disease that would normally be hard to detect but also pick up on early evidence of relapses.
Dr Nitzan Rosenfeld, senior group leader at the Cancer Research UK Cambridge Institute who led the team that conducted this research, said that while their work is still at an experimental stage, tests with “such sensitivity could make a real difference to patients”.
He said: “Personalised tests that can detect if cancer is still present, or find it early if it is returning, are now being tested in clinical trials. Whilst this may be several years away from clinical use, our research shows what is possible when we push such approaches to an extreme.
“It demonstrates that the levels of sensitivity we’ve come to accept in recent years in relation to testing for ctDNA can be dramatically improved.”
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Most current tests for cancer patients are overly invasive or can fail to accurately monitor progress in tumours. Tests that look for residual ctDNA in blood samples are less invasive but can be hard to detect because it is sometimes present in only tiny amounts in blood, especially in people with small tumours or residual disease.
But by using their new personalised method, the researchers were able to look “for hundreds and sometimes thousands of mutations in each blood sample”. This involved analysing the genetic make-up of an individual’s tumour and targeting a set of mutations specific to the patient.
Their test was able to detect ctDNA in patients with earlier-stage disease, where the level of ctDNA in the blood is much lower. This included patients with lung or breast cancer, as well as patients with early-stage melanoma who had already had surgery, the researchers said.
The scientists plan to use their method to help refine future tests for cancer early detection, as part of ongoing studies funded by Cancer Research UK.