Scientists have developed a blood test that could help detect cancer in individuals with nonspecific symptoms.
An earlier cancer diagnosis is strongly correlated with improved outcomes. The earlier a cancer is detected, the easier they typically are to treat. They are also less likely to have metastasised. Current cancer referral pathways are based around organ-specific symptoms (e.g., haematuria) or clinically demonstrable abnormalities (e.g., breast lumps). This process is more complicated for individuals who present with nonspecific symptoms (e.g., fatigue). Without typical symptoms, it can be difficult to know which specialist to refer a patient to. As a result, this can waste time and resources and may lead to delays in diagnoses.
To help identify patients with nonspecific symptoms, the Suspected CANcer (SCAN) pathway was established in the UK. It is a referral pathway from primary care to the hospital for patients with nonspecific symptoms. All patients referred undergo a contrast-enhanced CT of the chest, abdomen and pelvis as well as blood biochemistry and haematology analyses.
An alternative approach for this group of patients is biofluid metabolomics. This technique measures levels of small-molecule constituents within a biological sample to establish disease-specific patterns. These profiles are typically produced by nuclear magnetic resonance (NMR) spectroscopy or mass spectrometry. Previous studies have shown that NMR metabolomics can identify different cancers including lung, colorectal, liver, breast and bladder.
Metabolomic biomarkers identifies cancers
In a recent study, published in Clinical Cancer Research, researchers analysed samples from over 300 patients from the SCAN pathway. All patients had nonspecific symptoms of cancer, such as fatigue and weight loss. Blood was collected and analysed using NMR metabolomics.
The team found that the test was able to correctly detect cancer in 19 out of every 20 of those with the disease. It could also identify patients with metastatic disease in the cohort of cancer patients with 94% sensitivity and 88% specificity. The test, however, cannot yet pinpoint the specific tumour type, although this is a future goal.
Dr Fay Probert, lead researcher, said:
“This work describes a new way of identifying cancer. The goal is to produce a test for cancer that any GP can request. We envisage that metabolomic analysis of the blood will allow accurate, timely and cost-effective triaging of patients with suspected cancer, and could allow better prioritisation of patients based on the additional early information this test provides on their disease.”
This approach is not only sensitive, but it is also low cost, requiring nothing more than a simple blood sample and an inexpensive NMR analysis. Most importantly, this approach can identify patients with solid tumours when referred with nonspecific symptoms – a group which is typically hard to diagnose. The next step is to determine the accuracy of the test in 2,000-3,000 patients with nonspecific symptoms.
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