A simple blood test could detect more than 50 types of cancer before any clinical signs or symptoms of the disease are apparent, WalesOnline reports.
The technique called multi-cancer early detection (MCED) looks for DNA fragments that leak into vessels and arteries and could open the door to identifying previously hard to find tumours for removal before they spread. And the tests offer hope of beating "silent killers" such as those of the head and neck, ovaries, pancreas, gullet, cervix and prostate.
The DNA fragments carry chemical changes that differ from normal cells, indicating disease. It offers hope to screening programmes for older people and other vulnerable individuals.
A trial named PATHFINDER managed to pick up a signal in 1.4% of 6,621 over 50s who were believed to be healthy, and where it had come from in the body. A resolution was achieved within three months for almost 75% of those who had tested positive, with cancer confirmed in 38% of the cases.
It took an average of 79 days to diagnosis, or to decide there was no evidence of malignancy requiring further investigation. Of 6,290 individuals who were cancer free, more than 99% received a negative test result.
Dr Deb Schrag of Memorial Sloan Kettering Cancer Centre, New York, said: "The results are an important first step for early cancer detection tests because they showed a good detection rate for people who had cancer and an excellent specificity rate for those who did not have cancer. In people with a positive test, it took less than two months to confirm the diagnosis if they had cancer and it took a bit longer if they did not have cancer primarily because physicians opted to perform imaging studies and then repeat them a second time several months later to investigate the possibility of a cancer diagnosis.
"An important finding was that few participants with a false positive screening test required multiple invasive procedures such as endoscopies and biopsies. This finding should help to allay concerns that these tests could cause harm by generating unnecessary procedures in people who are well."
The study reported at a European Society for Medical Oncology (ESMO) meeting in Paris is the first to show an MCED test can detect cancer in undiagnosed patients. NHS England is piloting a blood test for more than 50 cancers after enrolling 140,000 people without symptoms to investigate its clinical effectiveness.
Professor Fabrice Andre of Gustave Roussy Cancer Treatment centre in France and co-chair of ESMO said the technology is set to revolutionise therapy. He said: "It is a duty of professional societies like ESMO to raise awareness of the fact that within the next five years, we will need more doctors, surgeons and nurses, together with more diagnostic and treatment infrastructure, to care for the rising number of people who will be identified by multi-cancer early detection tests.
"We need to agree who will be tested and when and where tests will be carried out, and to anticipate the changes that will happen as a result of these tests, for example in the diagnosis and treatment of people with pancreatic and other cancers that are usually diagnosed at a much later stage."
Despite the blood test's capabilities, Dr Schrag stressed the importance of continued standard screening for breast and colorectal cancer, especially while MCED tests are being refined and validated. At present, there are no such options for stomach, small bowel and pancreatic tumours which can often migrate to other organs before diagnosis.
Dr Schrag continued: "This study indicates hope is on the horizon for detecting cancers that are currently unscreenable, but of course much more work is needed and, with experience and larger samples, these assays (tests) will improve. The tests need to be refined so they are better at distinguishing tumour DNA from all the other DNA that is circulating in the blood."
"It is also critical to note that the purpose of cancer screening is not to decrease the incidence of cancer, but rather to decrease cancer mortality. t is premature to reach any conclusions about how MCED testing affects mortality which was not measured in the PATHFINDER study and requires lengthy follow-up."
The NHS hopes it will have its results some time in 2023 and has set a target of finding three-quarters of cancers at an early stage - when there is a higher chance of a cure. Professor Andre added: "We need comparative trials across all types of cancer to find out if having an early detection test affects morbidity and mortality.
"We also need to know how the tests benefit patients, and how to discuss the results with them. In addition, we need to know more about the small proportion of false positive tests - MCED results that indicate cancer is present but this is not confirmed by standard diagnostic procedures.
"We need some of these answers before we can calculate the cost impact of introducing MCED tests in routine clinical practice."
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