2.1 In the NHS, lung nodules are managed in line with the British Thoracic Society's guidelines for the investigation and management of pulmonary nodules (2015). The guidelines recommend the same diagnostic approach for nodules detected incidentally, due to symptomatic presentation, or through routine screening. People with nodules below 5 mm in diameter or 80 mm3 in volume are discharged without follow up. CT surveillance is offered for nodules between 5 mm and 8 mm in diameter or 80 mm3 and 300 m3 in volume. For nodules over 8 mm in diameter or 300 m3 in volume, the Brock model is used to calculate risk of malignancy. CT surveillance is offered to people with nodules that are below a 10% risk score using the Brock model.
2.2 The Herder model is used to calculate malignancy risk of nodules after a Brock risk assessment of 10% or above and a subsequent positron emission tomography CT (PET-CT) scan. For nodules with a Herder risk score below 10%, CT surveillance is offered. People with risk over 70% are considered for excision or non-surgical treatment. Within the intermediate group (between 10% and 70% risk of malignancy) the guidelines for subsequent care are more varied, with possible management options including image-guided biopsy, CT surveillance and excisional biopsy. Decisions are based on risk of malignancy, patient fitness and preferences and nodule characteristics.
2.3 Accurately differentiating between malignant and benign nodules as soon as possible is important. People have more treatment options and potentially better outcomes when lung cancer is diagnosed in its early stages. However, misdiagnosis of a benign nodule as malignant, could result in further imaging tests (with higher radiation exposure) or invasive procedures, such as biopsy or resection, which carry risks of adverse events.
2.4 EarlyCDT Lung could help identify malignant lung nodules that need immediate treatment or a biopsy. This could result in treatment being offered earlier, potentially giving improved patient outcomes. It could also reduce the number of people on CT surveillance, patient waiting times and radiologist time and enable more efficient use of NHS resources.
2.5 EarlyCDT Lung (Oncimmune) is a blood test to assess the malignancy risk of solid lung nodules found by chest CT or X-ray. It is an enzyme-linked immunosorbent assay and is available as a CE-IVD kit. EarlyCDT Lung measures the presence of autoantibodies to a panel of 7 lung cancer associated antigens (p53, NY-ESO-1, CAGE, GBU4-5, HuD, MAGE A4 and SOX2). After blood collection, the test is carried out in a laboratory in a secondary healthcare setting. Positive results are reported as 'positive-moderate' if at least 1 of the 7 autoantibodies is elevated above a predetermined 'low' threshold, but all are below the 'high' threshold. If at least 1 of the 7 autoantibodies is elevated above the 'high' predetermined threshold, the test is reported as 'positive-high'.
2.6 EarlyCDT Lung is proposed as a 'rule-in' test to be used in addition to standard care for the detection of lung cancer. A positive EarlyCDT Lung result would be used to update a pre-test malignancy risk from either the Brock or Herder risk models. The pre-test risk would be unchanged if the EarlyCDT Lung result is negative. The estimated post-test risk is intended to help clinicians make decisions about further testing or intervention.
2.7 The Brock model is used to calculate a nodule's risk of malignancy, which is based on patient characteristics (such as age, gender and smoking history) and on nodule characteristics. The Herder model is used to calculate malignancy risk after a Brock risk assessment of 10% or above and a PET-CT scan. The Herder model is based on patient characteristics, nodule characteristics, and the degree of F-fluorodeoxyglucose uptake on PET-CT.