A ‘potentially revolutionary’ blood test that could detect a range of different types of cancer is to be trialled by the NHS in a world-leading programme, NHS chief executive Sir Simon Stevens announced today.
The new test, known as the Galleri blood test, was developed by the company GRAIL and aims to detect cancers early by looking for abnormal DNA shed from cells into the blood.
So far, the blood test has only been trialled on people with signs of cancer, but the latest NHS England pilot will test if it can spot cancer in people without symptoms.
“Earlier detection of cancer offers arguably the single biggest opportunity to save lives from the disease, and tests like GRAIL’s have great transformative potential. Large research studies of these tests are essential for determining if they’re effective, and a vital step in getting them to patients, if proven to work.” – Michelle Mitchell, Cancer Research UK’s chief executive.
What do we know about the test so far?
The Galleri blood test looks for abnormal DNA that has been shed from cancer cells into the blood. DNA from cancer cells often have differences in the chemical tags that sit on the DNA compared with DNA from healthy cells – differences the test is designed to exploit.
A number of studies have looked to refine the use of this blood test for cancer detection outside the UK. GRAIL themselves have been investigating the use of artificial intelligence in the interpretation of the blood test results. Cancer Research UK covered some of the findings released by GRAIL earlier this year.
Results from these studies have so far been promising, and a particular focus point for good news is the large number of cancer types that it seems to be able to pick up, including some cancer types that are considered difficult to diagnose early, including head and neck, ovarian, pancreatic, oesophageal and some blood cancers.
However, there are some questions that remain unanswered.
As our head of early diagnosis, Jodie Moffat, explains, one of the challenges that arises from this type of test is how difficult it is to detect very small quantities of abnormal DNA circulating in the blood. Because the amount of circulating tumour DNA tends to increase as a cancer becomes more advanced, these types of blood tests tend to be better at picking up later stage disease. Based on the results we have seen so far, the test is not currently that good at picking up stage 1 cancer, where the cancer is small and hasn’t spread to other parts of the body.
What’s more, the number of cancers that have been analysed, particularly for some rarer cancer types, has been very small. The NHS pilot is an opportunity to trial the test in a much larger sample, with longer follow up of patients not testing positive and a chance to iron out some of these limitations.
The findings of this large scale research project will also be key to understanding the negative impacts of the test – including measuring the number of people who test positive but don’t go on to be diagnosed with cancer and if any cancers are missed by false negatives, as well as the impact of the process and results on people’s mental health.
Another key factor is that the researchers ensure the test is accessible to all and doesn’t exacerbate inequalities and that people taking part in the study are representative of the UK’s diverse population.
The pilot study
The GRAIL pilot is due to begin later next year with 165,000 participants in total. This will include 140,000 people aged 50 to 79 who will be identified through NHS records and asked to take part. This group will have no symptoms and will have annual blood tests for 3 years. Anyone with a positive Galleri blood test result will be referred for further investigation in the NHS.
A further 25,000 people with possible cancer symptoms will also be offered testing once they have been referred to hospital in the usual way, to see if Galleri could be used tospeed up their diagnosis. This might be particularly helpful when patients experience symptoms that could be linked to several different types of cancer. .
Results from these studies are expected to be released by 2023. If outcomes from these initial pilots are positive, the studies will be expanded to involve around 1 million participants in 2024 and 2025.
Importance of early diagnosis
Cancer that’s diagnosed at an early stage, when it isn’t too large and hasn’t spread, is more likely to be treated successfully. Right now, in England about 55% of cancer cases that can be staged are diagnosed in the earliest stages (stage 1 and 2).
“All too often, people are diagnosed with cancer at a late stage, when their disease is more difficult to treat. This is a human tragedy, not just in terms of lives lost, but it also means more expensive treatments, hospital stays and monitoring,” says Mitchell. “If we can find cancer at its earliest stages when it’s easier to treat, not only will we be able to save lives on a vast scale, but we may be able to save our NHS millions of pounds.”
The NHS Long Term Plan, published at beginning of 2019, aims to increase the number who are diagnosed early so that by 2028, 75% of cancers will be diagnosed at the earliest stages (stage 1 or 2). The Galleri blood test could be play a part in making that goal a reality. The results of the pilot will be key to understanding if this could be the case.
While this test looks promising and this research may provide useful evidence, one test alone is unlikely to be able to transform the entire healthcare system to deliver early detection for all. We mustn’t take our eye off the need for other research and piloting, and speedy implementation of the things we already know work well.
Earlier this year, Cancer Research UK set out an Early Detection Roadmap to address some of the problems and challenges facing the entire early diagnosis ecosystem, from the development of new tests, through to boosting capacity in diagnosis.
This will still require vital investment in more NHS equipment and workforce, investment that we’ve called for many years. Yesterday, the chancellor Rishi Sunak announced some welcome funding for the NHS in the UK Government’s spending.
“The announcements from the Government in the spending review yesterday were a step in the right direction, but we will need further long term investment in both cancer services and research and development to make early detection of cancer a reality for every patient,” says Mitchell.