A ground-breaking new blood test that can detect eight common types of cancer before they spread will save countless lives, reports The Guardian. Scientists believe that the 'liquid biopsy' – developed in the US – will be a game-changer in the fight against cancer, and hope it could be widely available within a few years.
The report says the test was able to detect tumours about 70% of the time on average in more than 1,000 patients with early-stage cancer. Crucially, it did so before the cancers had spread, giving patients the best chance of beating the disease.
It works by looking for mutated DNA that dying cells shed into the blood, and protein biomarkers associated with bowel, breast, liver, lung, oesophageal, ovarian, pancreatic and stomach cancer.
Professor Peter Gibbs, from the Walter and Eliza Institute in Melbourne, who has worked on the test, dubbed CancerSEEK, said he thought it would save thousands of lives. He hoped it would become widely available, and affordable, before too long. “For the first time we’re seeing a potential for a blood test that can screen for many types of nasty cancers that up until now, we’ve had to wait until symptoms [arise] and diagnose quite late,” Gibbs is quoted in the report as saying.
It has proved effective in detecting cancers, such as pancreatic cancer, that often result in few if any symptoms until the disease is well advanced, often meaning death for the patient.
Gibbs said many more people would be willing to have a simple blood test than undergo unpleasant and invasive screening procedures, such as colonoscopies.
With cancer risks rising from the age of 50, he said, the test would be most important to older people, but also for younger people whose family histories might put them in a high-risk category.
The report says the test, developed by researchers at Johns Hopkins University in the US, is now being tested on 10,000 more people.
“The big question is going to be the cost,” Gibbs said. “I suspect currently you’re looking at $1,000 or something like that … but as with most technologies, and scale, things get a lot cheaper over time … hopefully that’ll drop to a few hundred dollars.”
Earlier detection is key to reducing cancer deaths. Here we describe a blood test that can detect eight common cancer types through assessment of the levels of circulating proteins and mutations in cell-free DNA. We applied this test, called CancerSEEK, to 1,005 patients with non-metastatic, clinically detected cancers of the ovary, liver, stomach, pancreas, esophagus, colorectum, lung, or breast. CancerSEEK tests were positive in a median of 70% of the eight cancer types. The sensitivities ranged from 69% to 98% for the detection of five cancer types (ovary, liver, stomach, pancreas, and esophagus) for which there are no screening tests available for average-risk individuals. The specificity of CancerSEEK was > 99%: only 7 of 812 healthy controls scored positive. In addition, CancerSEEK localized the cancer to a small number of anatomic sites in a median of 83% of the patients.
Joshua D Cohen, Lu Li, Yuxuan Wang, Christopher Thoburn, Bahman Afsari, Ludmila Danilova, Christopher Douville, Ammar A Javed, Fay Wong, Austin Mattox, Ralph H Hruban, Christopher L Wolfgang, Michael G Goggins, Marco Dal Molin, Tian-Li Wang, Richard Roden, Alison P Klein, Janine Ptak, Lisa Dobbyn, Joy Schaefer, Natalie Silliman, Maria Popoli, Joshua T Vogelstein, James D Browne, Robert E Schoen, Randall E Brand, Jeanne Tie, Peter Gibbs, Hui-Li Wong, Aaron S Mansfield, Jin Jen, Samir M Hanash, Massimo Falconi, Peter J. Allen, Shibin Zhou, Chetan Bettegowda, Luis Diaz, Cristian Tomasetti, Kenneth W Kinzler, Bert Vogelstein, Anne Marie Lennon, Nickolas Papadopoulos
UK experts said it was "enormously exciting". However, one said more work was needed to assess the test's effectiveness at detecting early-stage cancers. Dr Gert Attard, team leader in the Centre for Evolution and Cancer at the Institute of Cancer Research, London, and consultant medical oncologist at the Royal Marsden NHS Foundation Trust, is quoted in a BBC News report as saying: "This is of massive potential. "I'm enormously excited. This is the Holy Grail – blood test to diagnose cancer without all the other procedures like scans or colonoscopy."
He said "we're very close" to using blood tests to screen for cancer as "we have the technology". But he cautioned there was still uncertainty about what to do when a cancer was diagnosed. In some cases, the treatment may be worse than living with a cancer that is not immediately life-threatening.
Men can already have slow growing prostate cancers closely monitored rather than treated. "When we detect cancer in a different way, we can't take for granted that everyone will need treatment," Attard said.
Professor Richard Marais, from Cancer Research UK, said in the report that it would take time to prove that it worked as an early diagnosis for cancer – at least five to six years. "Detecting cancer early, before the disease has spread is one of the most powerful ways to improve cancer survival and this interesting research is a step towards being able to do this earlier than is currently possible."
Paul Pharoah, professor of cancer epidemiology at the University of Cambridge, said more work was needed to assess how the test performs when cancers are less advanced. He said: "Demonstrating that a test can detect advanced cancers does not mean that the test will be useful in detecting early stage symptomatic cancer, much less pre-symptomatic cancer. The sensitivity for the stage 1 cancers in the study was only 40%."
And Dr Mangesh Thorat from the Centre for Cancer Prevention, Queen Mary University of London, said in the report that it looked promising "but with several caveats. A significant amount of further research is needed before we can even contemplate how this might play out in screening settings," he said.
"This is only a case-control study, and therefore needs further evaluation in large cohorts more representative of general population where such screening might be introduced."
The cost of CancerSEEK is less than $500 (£360) per patient, which is around the same price as a colonoscopy.
[link url="https://www.theguardian.com/australia-news/2018/jan/19/new-blood-test-could-help-detect-eight-common-cancers-before-they-spread"]The Guardian report[/link]
[link url="http://science.sciencemag.org/content/early/2018/01/17/science.aar3247"]Science abstract[/link]
[link url="http://www.bbc.com/news/health-42736764"]BBC News report[/link]