New research leads to Trust action to spot cancer warning signs in standard blood tests

Scientists at the University of Exeter have found a new way of interpreting standard blood tests to help GPs spot cancer warning signs – and the test is now being integrated in an NHS trust.

The Royal Devon University Healthcare NHS Foundation Trust (RDUH)  is the first Trust to apply a new algorithm to  routine blood analysis. It will mean they can detect differences in raised blood platelet levels in a more tailored way, and flag any concerns to GPs to investigate.

When a  patient has a blood test at a GP practice, they’re processed through a hospital-based laboratory. In Devon, the RDUH team conducts around 500,000 blood tests that include a platelet reading each year. Initially, the new analysis will be piloted on tests from five practices or medical centres in the county.  In this pilot group, the research team estimates that the new algorithm  would flag around 500 patients with raised platelets each year, with around 20 people in that group having cancer that would be caught earlier. Where a patient has a high platelet count, the GP will be notified as part of the results sent back to them. Crucially, the system includes providing clear guidance to the GP on what steps to take next to assess whether the reading warrants further investigation.

The initial pilot is expected to run for two years, including a staged expansion in specific regions. If  rolled out across NHS, experts believe it could flag 10,000 patients a year who have a raised blood platelet count before their cancer diagnosis. Recognition of this early warning sign could lead to earlier diagnosis and better patient outcomes.

Platelets are tiny blood cells that help the body form clots to stop bleeding. Blood tests already include a platelet count as standard – and a high platelet count can sometimes be an indicator of certain types of cancer, including lung and bowel cancers.

Levels of platelets vary depending on age, and whether a person is male or female. However, this variation is currently not considered when doctors are interpreting platelet count results and deciding whether they might indicate cancer.

The Exeter team’s study, published in Cancers journal, and funded by philanthropist David Walton, reviewed data from more than six million adults over the age of 40 in Canada, England and Australia. Scientists found that natural variation in platelet count could be used to diagnose cancer sooner, with different platelet count levels indicating a higher risk of cancer for different patients. These results could be used to put new thresholds in place which take into account individual variation, creating a more personalised approach to interpreting blood test results.

Professor Sarah Bailey, Associate Professor of Primary Care Diagnostics at the University of Exeter, led the study. She said: “General practitioners know  that a raised platelet count can be an early sign of cancer. This study will give them more information about when this should be taken as a warning sign, and how to act on it. This study paves the way for more tailored interpretation alongside practical advice for GPs about next steps. We’re delighted to see it in action in Devon already, and we hope to see it rolled out even further, to benefit patients and potentially save lives.”

Professor Tim McDonald, Clinical Director for Pathology at the Blood Sciences Laboratories at the  Royal Devon University Healthcare (RDUH) NHS Foundation Trust, said: “This research really is a win-win for improving cancer diagnosis. It’s actually very simple for us to add to the routine tests we’re already conducting, and we hope it will mean that GPs can catch cancer in some patients earlier, which we know leads to the best outcomes.”

Nada Khan, an Exeter-based GP, said: “This research has already made a big impact on how GPs interpret high platelet counts in practice and is an important step towards implementing robust systems to flag blood results in patients with a high platelet count. This could really help GPs to identify when it is appropriate to refer patients for further investigations and referrals and ultimately could lead to earlier diagnosis for some patients.”

David Gibbs is Pathology Network Director at the Peninsular Pathology Network, which supports  blood tests across Devon and Cornwall. He said: “The beauty of these personalised thresholds is that they maximise the impact of existing services for diagnosis. This research will improve outcomes for patients and help clinicians to manage the demands placed on the health system.”

David Walton, a philanthropist with an interest in cancer, funded the study. He said: “I’m very happy to support the project. The work that Professor Bailey and her team are doing to help find cancer early is still one of the most effective ways of fighting the disease. The potential impact of this work is very exciting.”

In the project, entitled  High or Elevated Level of Platelets (HELP) Flag, researchers used anonymised electronic health records to conduct the study. They analysed  records from patients who had a blood test for any reason during one calendar year, and followed up to identify how many were subsequently diagnosed with cancer, which type, and how that diagnosis was made. Half of patients with cancer who were not investigated with an urgent referral were diagnosed after an emergency presentation. Investigating these individuals when they had a raised platelet count could avoid that emergency route, which is associated with poor outcomes and worse survival.

The University of Exeter, the Peninsula Cancer Alliance, and RDUH are conducting an evaluation via the National Institute for Health and Care Research (NIHR) Exeter Biomedical Research Centre and Exeter HealthTech Research Centre, to analyse the extent to which implementing the new test triggers earlier diagnosis warnings, and to roll out the approach further if successful.

The research paper ‘Improving the Clinical Utility of Platelet Count for Cancer Detection in Primary Care: A Cohort Study in England, Canada, and Australia’and is published in Cancers.