Innovative blood test improves lung cancer screening accuracy
Last reviewed: 14.06.2024
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In a recent study published in Cancer Discovery, researchers developed and validated a blood-based cell-free DNA fragment assay (cfDNA) to detect lung cancer, which, in the case of positive results, accompanied by low-dose computed tomography (LDCT).
Lung cancer is a leading cause of death, and annual screening is important. However, low acceptance of LDCT due to patient barriers such as lack of awareness, concerns about radiation, and limited availability poses challenges. Other difficulties include poor recording of smoking history, lack of specific practices and specialist follow-up.
In the DELFI-L101 study, researchers developed a hematology test using machine learning to analyze DNA fragments and identify people at risk of lung cancer. Those who test positive are referred to LDCT.
Since March 2021, researchers have enrolled 958 people aged 50-80 years with a smoking history of ≥20 pack-years at 47 US sites. Participant selection criteria met the 2015 National Health Survey (NHIS) LDCT screening criteria.
Individuals with cancer therapy within a year, history of hematologic malignancies or myelodysplasia, organ transplantation, blood transfusion within 120 days, pregnancy, and participation in other studies were excluded.
The researchers observed a test specificity of 58%, a sensitivity of 84%, and a negative predictive value (NPV) of 99.8%. When applying the test to a screening-eligible population with a 0.7% lung cancer prevalence, the number needed to screen (NNS) was 143.
Validation results showed that negative and positive results were associated with NNS using LDCT to detect 414 and 76 cases, respectively, resulting in a relative risk value of 5.5. The positive predictive value (PPV) was almost twice as high as using LDCT selection criteria alone.
Analysis of cfDNA fragments from lung squamous cell carcinoma (LUSC) patients revealed a component resembling cfDNA profiles in healthy individuals and another resembling the open and closed regions of chromatin noted in LUSC tissues.
The study shows that DNA fragment analysis provides a new, accurate, accessible tool for the initial assessment of lung cancer followed by the use of LDCT.
This test may help prevent lung cancer-related deaths, with moderate acceptance rates that may reduce late-stage diagnoses and deaths.