Computed tomography (CT) is used routinely to study various respiratory ailments, including lung cancer. The routine use of CT is leading to the detection of an increasing number of lung nodules. Most of these nodules, even in high-risk patients, are benign,  yet their detection alters patients’ quality of life as it may lead to invasive testing or uncertainty during radiological follow-up.

According to the scientific society, current recommendations regarding the management of nodules measuring between 6 and 15 mm in diameter vary. Diagnostic options include a follow-up CT scan, PET CT nodule characterization, or biopsy, depending on nodule characteristics (size, speculation, location) and patient risk factors (age, smoking, family history). PET CT scanning, which is essential for staging patients with lung cancer or characterizing nodules bigger than 15 mm in diameter, lacks sufficient sensitivity and specificity for smaller nodules. In a wait-and-see approach, the rate of nodule duplication in 3-6 months is often the only criterion used to recommend a biopsy.

In this context, the use of biomarkers (circulating DNA, microRNA or autoantibodies) associated with the presence of lung cancer is being investigated. The EarlyCDT-Lung test has been validated for the characterization of indeterminate lung nodules. A blood test identifies antibodies to a panel of seven tumour antigens associated with lung cancer. The accuracy of the test is 92%, with an average sensitivity and specificity of 41% and 93%, respectively, for lung cancer.