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The NHS has launched the world’s largest trial for a new cancer detection test

The NHS England has recently announced the launch of a new blood test, which can detect over 50 different types of cancer.

The current landscape of cancer testing

In the UK, screening programs are available for three cancer types (bowel, cervical and breast cancer). The introduction of cancer screening programs has led to early diagnoses and, ultimately, increased the chances of survival for a huge number of patients across the world. This is because treatment is typically more successful when the tumour isn’t too large or hasn’t yet metastasised.

Currently, the UK has a few different approaches that help to diagnose cancer, including physical examinations and imaging, or the testing of invasive biopsies. However, current techniques are limited due to their invasive nature and lack of ability for continued disease monitoring.

The Galleri blood test

To combat some of the challenges that exist with current approaches, the NHS has launched a new trial that aims to test for the earliest signs of cancer in the blood before symptoms appears. The trial titled: ‘The NHS-Galleri trial’ is the first of its kind. It is hoped that this simple and quick blood test will revolutionise cancer detection and treatment.

The Galleri blood test was developed by the company GRAIL, which was very recently acquired by Illumina. The diagnostic test aims to detect multiple cancer types early by looking for cell-free DNA (cfDNA). cfDNA is shed by both tumour and healthy cells into the bloodstream. The Galleri test uses genetic sequencing technology and artificial intelligence to scan for patterns of chemical changes in the cfDNA from cancer cells.

What do we know so far?

The Galleri blood test has been trialed in people who have already been diagnosed with cancer. So far, the results from previous studies have shown that the Galleri blood test can detect 50 different types of cancer with a low false-positive rate of 0.5%. GRAIL also reported that the test is able to accurately detect cancer in 51.5% of individuals. Of these 51.5%, the test can correctly predict the tumour location in 89%. Their research has also shown that the test is particularly effective at finding cancers that are difficult to identify early, such as neck, bowel, lung and throat cancers. 

Nonetheless, a key challenge for this test is detecting a minimal amount of abnormal cfDNA. Typically, the amount of cfDNA increases as cancers becomes more advanced. Most of the blood tests similar to Galleri are best at detecting later stages of the disease. However, the current reported results show that the Galleri test is still able to effectively pick up Stage 1 cancers.

The roadmap for the Galleri trial

The NHS-Galleri trial is the largest NHS trial to date. The team are aiming to recruit 140,000 volunteers across eight areas of the UK, between the ages of 50 and 77, who have not had a cancer diagnosis in the last three years. These volunteers will be asked to give a blood sample at a locally based clinic, and they will be invited back after 12 months and again after two years.

The volunteer cohort will be split into two groups. One group will have their samples screened by the Galleri test straight away, while the other group’s samples will be put in storage and tested in the future. This will enable the scientists to draw a comparison between which cancers are detected between the groups. The participants will not be aware of which group they are in unless the Galleri test detects a possibility of cancer.

The team are expecting the initial results in 2023, and if successful, the NHS hopes to extend the rollout to a further 1 million people in 2024 and 2025.

“It is an absolute priority to speed up the earlier detection of cancer to improve survival, and this trial has the potential to do just that across a range of types of cancer. We are very grateful to all the people who will be taking part in this important initiative, which could help us save many more lives in the future.” said Dame Cally Palmer, NHS National Director for Cancer.

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