The GALLERI trial - exciting development or unwelcome distraction?

Professor Gordon Wishart, Chief Medical Officer at Check4Cancer gives his comment on the recent announcement by the NHS on the GALLERI trial using the multi- cancer blood test from GRAIL; is this an exciting development or an unwelcome distraction? 

Prof Gordon Wishart Head Shot

Professor Gordon Wishart is Chief Medical Officer at Check4Cancer and Visiting Professor of Cancer Surgery at Anglia Ruskin School of Medicine.

NHS England Chief Executive Sir Simon Stevens has announced that a blood test designed to detect more than 50 types of cancer will be trialled by the NHS next year. As founder of an early cancer detection company, I applaud any attempts to improve cancer survival by detecting cancer at an earlier stage but, is it too soon to describe this test as a “world-leading gamechanger in cancer care”?

The proposed GALLERI trial will start in 2021 and test 140,000 men and women with no cancer symptoms for the next three years, as well as 25,000 with possible cancer symptoms, and those with a positive test with require further investigation by CT or MRI scanning. So, what is the current evidence for the test and is it likely to be more applicable for cancer screening or diagnostics?

A paper published in the Annals of Oncology in March 2020 analysed blood from 1,264 individuals with or without cancer and, reported that the test was more likely to detect an underlying cancer with increasing stage of the disease. These numbers are small and not all the participants with cancer were asymptomatic, therefore, this test may not be applicable for population screening. Across the world cancer screening, such as the NHS breast and bowel screening programmes, have been introduced following randomised clinical trials that assessed the survival benefit for the screening intervention and measured any harm from investigation of false-positive results and potential over-treatment.

The GALLERI trial will not provide this information but, it may help understand the ability of the test to detect people with early-stage cancers before symptoms arise and open the door to future screening trials. However, perhaps the most interesting use of the test could be to help detect and diagnose patients with cancers that traditionally present at a more advanced stage, such as lung, pancreatic, ovarian or bowel cancer. This test could therefore make a significant difference to the treatment and outcome of these cancers if the ability to diagnose them at an earlier stage is confirmed in a larger study.

My biggest concern at present, however, is that the announcement of this trial will provide little comfort for the millions of men and women who have missed screening appointments in 2020 due to government lockdown and restrictions. In fact, many may view this press release as an unwelcome distraction. So, before we get carried away with game-changing and world-beating cancer care, I would encourage the NHS to clarify when these missed screening appointments will be reinstated and, to invest in modernising the current screening pathways by introducing at-home self-sampling for cervical screening, making the FIT test more sensitive for bowel screening and introducing risk-stratified breast screening. These changes would have a more immediate impact to improve cancer survival in the UK while we continue to develop the technological advances of the future.