504MO Validation of a spectroscopic liquid biopsy for the earlier detection of brain cancer

Abstract

Background
Brain cancer has a very high fatality rate with only one third of patients surviving five years or more after a diagnosis. Early referral for brain imaging is crucial, but existing symptom-based referral guidelines inadequately stratify patients for brain imaging. Delayed detection leads to 62% of brain tumor patients receiving a diagnosis when they present to the emergency department (ED). A liquid biopsy could rapidly triage the symptomatic population in primary care. The most at-risk patients would be fast-tracked for urgent brain imaging, whereas those with a negative result can be monitored with routine follow-up.
Methods
We initially recruited 988 patients prospectively with non-specific symptoms associated with a brain tumor in NHS Lothian (Edinburgh, UK). Patient blood serum samples were analyzed using the Dxcover® Brain Cancer liquid biopsy. This technology utilizes infrared spectroscopy combined with a diagnostic algorithm to predict the presence of intracranial disease. Sensitivity analysis explored cost-effectiveness across possible combinations of sensitivity and specificity defined by the receiver operating characteristic (ROC) curve. Thereafter, an additional 500 patients were recruited for a verification study, in preparation for an EU-IVDR Performance Evaluation trial. In this clinical performance study, multiple sites across the UK and Europe will collect and analyze patient samples for clinical validation of the test.
Results
In our initial feasibility studies, the liquid biopsy reported an area under the ROC curve of 0.8. The algorithm detected 96% of the patients with brain tumors, and the diagnostic models can be tailored towards higher sensitivity (or specificity) depending on clinical priorities. We will also present the results of our verification study, the cost-effectiveness analysis and an interim analysis of the EU-IVDR trial at the meeting.
Conclusions
This simple, non-invasive blood test facilitates the triage and radiographic diagnosis of brain tumor patients, while providing reassurance to healthy patients. By decreasing the time to diagnosis, the morbidity from treatment can be reduced, which in turn would improve the quality of life of brain cancer patients.