The test correctly detected the form of cancer in 96 per cent of the samples
A simple blood test can screen for more than 50 forms of cancer, scientists claim, sometimes before any signs or symptoms.
It may help to detect tumours sooner so they are easier to treat and hopes doctors, hopefully, to cure.
More than 99 percent of the positive findings are correct, the team says, but ensuring that it does not neglect cases and offers false assurance will be important, reports the BBC.
Doctors are using it in patient trials but, they claim in Annals of Oncology, further studies are needed.
Trial research shows that it can easily diagnose more advanced disease than cancer origins, which may restrict how useful it is.
How does it work?
The test searches for telltale chemical changes to the bits of genetic code-cell-free DNA-that leak into the bloodstream from tumours.
The researchers, along with UK colleagues from The Francis Crick Institute and University College London from the Dana-Farber Cancer Institute and Harvard Medical School, examined more than 4,000 samples from patients-some with and some without cancer.
It contained more than 50 forms of cancer, including intestinal, lung, and ovarian.
And the test correctly detected the form of cancer in 96 per cent of the samples.
What do experts say?
The study is funded by Grail, the maker of the blood test.
One of the lead researchers, Prof Geoff Oxnard, said, "This blood test seems to have all the features needed to be used on a population scale, as a multi-cancer screening test.
"Everyone asks when will a test like this will be ready for use.
"Based upon this successful clinical validation in thousands of patients, the test has actually now been launched for limited use on clinical trials.
"But before this blood test is used routinely, we will probably need to see results from clinical studies like this to more fully understand the test performance.
"Certainly the field is moving quickly and it makes us hopeful that blood-based cancer detection will be a reality."
Cancer Research UK early detection head Dr David Crosby said, "Detecting cancers at their earliest stages, when they are less aggressive and more treatable, has a huge potential to save lives and we sorely need tech innovations that can turn this potential into reality.
"Although this test is still at an early stage of development, the initial results are encouraging.
"And if the test can be fine-tuned to be more efficient at catching cancers in their earliest stages, it could become a tool for early detection.
"But more research is needed to improve the test's ability to catch early cancers and we still need to explore how it might work in a real cancer-screening scenario."