P2.11-10 Potential Utility of a Positive EarlyCDT®-Lung Blood Biomarker Test in Indeterminate Pulmonary Nodules

EarlyCDT®-Lung is a blood-based biomarker of risk for lung cancer and is able to detect early stage disease. Indeterminate pulmonary nodules (IPN) of 8-20 mm are a common clinical problem. Approximately 20% of IPNs are malignant in many series, but determining which ones are malignant versus benign is a dilemma. The ACCP guidelines recommend surgical resection for IPN of high risk for malignancy (>65%). A moderate positive EarlyCDT-Lung (sensitivity 40%; specificity 93%) has been shown to increase the risk of malignancy in IPNs of intermediate risk (10-65%) (Massion et al J Thorac Oncol 2017). We evaluated 48 patients from a clinical audit with an IPN and a calculated risk of malignancy of >30% based on the Mayo/Swensen calculator. Twenty-five patients had benign nodules and 23 were proven to be lung cancer. The positive predictive value (PPV) of the calculator alone was 48%. The biomarker test was positive in 23% (11 of 48) of the population (>30% risk). Ten of these 11 were proven to be lung cancer and one was benign; PPV of 91%. This 9% rate for benign disease is a marked improvement from the average resection rate of 20-25% for benign disease that has been reported in multiple lung cancer screening trials (24% in NLST). Combining the EarlyCDT-Lung blood test with calculated risk of IPNs of >30% resulted in a high PPV and would result in a resection rate of IPNs for benign disease of <10%. A prospective clinical utility study with EarlyCDT-Lung and IPNs is planned.