EARLY DIAGNOSIS OF PULMONARY NODULES: BIOMARKER PERFORMANCE IN CANCER SUBTYPES FOUND IN THE PANOPTIC STUDY

SESSION TITLE: Lung Cancer SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2018 01:00 PM - 02:00 PM PURPOSE: The PulmonAry NOdule Plasma proTeomIc Classifier (PANOPTIC) study clinically validated the biomarker. The biomarker combined clinical risk factors with protein expression in patients with newly diagnosed incidental lung nodules to stratify the risk of malignancy. Given the potentially different biology involved in differing cancer subtypes, the performance of the classifier was analyzed across subtypes found in the study. METHODS: The integrated classifier, Xpresys Lung (Integrated Diagnostics, Seattle, WA), is a blood test designed to evaluate patients age 40 years and older with an 8-30mm nodule, integrating the protein levels with 5 clinical factors in those with a pre-test probability of cancer (pCA) being ≤ 50%. The entire population and the cancer subtypes were evaluated for test performance. Pairwise evaluation was conducted using the Marascuillo procedure RESULTS: Total patients eligible for analyses were 392 and 178 were intended use (pCA≤50%) with a cancer prevalence of 16% and mean nodule size of 16.8 ± 0.6 mm. The overall performance was: sensitivity 97%, specificity 44%, NPV 98%. Clinical utility calculations were: reduction in invasive procedures 40%, 3% of malignant nodules to surveillance (compared to 45% actual). Of the 178 lower-risk patients, 29 had a malignant nodule and 149 a benign nodule. Cancer subtypes were represented by 17 (59%) adenocarcinoma, 4 (14%) squamous cell, 1 (3%) non-specific NSCLC, 2 (7%) small cell, 3 (10%) carcinoid and 2 (7%) non-specific other cancers. As shown in the table, the integrated classifier performed similarly in all subtypes. The results were analyzed in a pairwise fashion using the Marascuillo procedure with none of the comparisons reaching statistical significance.Table: Integrated Classifier performance in cancer subtypesGroup Cancer Benign Total SEN SPEC PPV NPVPanoptic LR 29 149 178 97% 44% 25% 98%NSCLC 22 149 171 100% 44% 21% 100%Adenocarcinoma 17 149 166 100% 44% 17% 100%Squamous Cell 4 149 153 100% 44% 5% 100%Non-Specified 1 149 150 100% 44% 1% 100%SCLC 2 149 151 100% 44% 2% 100%Carcinoid 3 149 152 100% 44% 3% 100%Other 2 149 151 50% 44% 1% 98% CONCLUSIONS: The PANOPTIC study did not show any difference in classifier performance for the cancer subtypes found in the study. However, the small numbers observed in many of the subtypes preclude conclusions. CLINICAL IMPLICATIONS: A newly developed blood based biomarker may help determine whether an incidental nodule is benign regardless of histology. DISCLOSURES: Employee relationship with Integrated Diagnostics Please note: >$100000 Added 03/05/2018 by Paul Kearney, source=Web Response, value=Salary Employee relationship with Integrated Diagnostics Please note: >$100000 Added 03/02/2018 by alexander porter, source=Web Response, value=Salary Employee relationship with Integrated Diagnostics Please note: >$100000 Added 03/02/2018 by Steven Springmeyer, source=Web Response, value=Salary