MA23.03 Risk Assessment for Indeterminate Pulmonary Nodules Using a Novel, Plasma-Protein Based Biomarker Assay

Abstract

To reduce overdiagnosis and overtreatment of non-cancerous pulmonary nodules found on CT scans, a noninvasive and easily administered test is needed to assess clinically significant disease risk. Such an assay should also accurately inform whether additional aggressive evaluation, including lung biopsy or thoracic surgery, is warranted. Objective: To determine the performance of a novel, plasma-based multiplexed protein test model when compared to the Veterans Affairs Clinical Factors Model (VA model) for discriminating between a lung cancer diagnosis established pathologically and an Indeterminate Pulmonary Nodule (IPN) found to be clinically and radiographically stable for at least one year. The protein biomarker-based risk model had been trained and tested with a cohort of 277 subjects at high risk of lung cancer, aged 25-85, who were current smokers with an indeterminate lung nodule 4-30mm in diameter (121 subject training set; 59 subject test set) from eight medical centers across the US. Using retrospective plasma samples, we compared the protein biomarker model results with the malignant or benign outcomes in an independent validation cohort comprised of 97 subjects from the Vanderbilt University medical center. Among the 97 validation study subjects (average age 60.1 years, range 42-83; average nodule size 16.1mm), the protein biomarker model correctly identified as benign or malignant an additional 44 of the 68 (65%) indeterminate pulmonary nodules classified as having intermediate risk by the VA model. Negative predictive value was 0.94. Only three patients with malignant disease were missed (94% sensitivity) while an additional 28 intermediate risk samples (41%) were properly classified as true positive, thus potentially avoiding aggressive interventions in those subjects with benign disease. This study evaluated a novel plasma protein biomarker assay model as a noninvasive risk assessment aid for characterizing indeterminate pulmonary nodules. When the model results are combined with the VA model, risk stratification for benign nodules is improved compared to current methods in clinical practice. We hypothesize patients with benign disease may benefit the most from this assay by avoiding unnecessary lung biopsy and subsequent overtreatment, while improving patient quality of care and reducing risks from these procedures. Providers and their patients in whom they suspect lung cancer may consider using this novel assay prior to proceeding with more aggressive interventions.