P2.01-77 PET CT Radiogenomic Depiction with EGFR and ALK Molecular Alterations in Lung Cancer Among Indian Population

Abstract

Non small cell lung cancer (NSCLC) represents an area of paramount importance wherein patients undergo testing for targetable genetic alterations. Association between the imaging and molecular phenotypes is vital highlighting the growing importance and unmet need of classifications based on radio genomic characterization. This study was conducted to evaluate the correlations between the radiologic and molecular phenotypes in patients with NSCLC. 211 patients with lung cancers during the study period of one year from October 2017 till November 2018 in our institution and undergoing both radiologic (PET-CT) and molecular investigations [Epidermal Growth Factor Receptor (EGFR), Anaplastic lymphoma kinase (ALK)] were included in the study. Both quantitative and qualitative CT findings were evaluated and correlated with the molecular findings. Quantitative data included SUV max obtained from PET component of CT and maximum diameter of lesion according to the RECIST criteria. Qualitative data recorded included location, pleural tail, pleural effusion, pericardial effusion, opacity, margins, calcifications, obstructive changes, pleural nodules, lung nodules, invasion, air bronchogram, emphysema, pulmonary fibrosis, mediastinal lymph nodes and distant metastasis. Statistical analysis was performed to evaluate the association of the qualitative features with the molecular expression. Receiver operating characteristic curves (ROC) were drawn and the corresponding area under curve (AUC) was calculated. P-values <0.05 were considered significant. Overall, EGFR mutation positivity and ALK rearrangement was observed in 114 and 37 patients, respectively whereas 60 patients had neither of these. SUV max was comparable between the groups with EGFR mutation (11.3 ± 3.9) and ALK rearrangement (12.3 ± 4.0). Correlations were observed between EGFR mutation and ALK rearrangement and location (p-value <0.0001), pleural tail (p-value <0.0001), pleural effusion (p-value <0.0001), obstructive changes (p-value <0.025), pleural nodule (p-value <0.002), lung nodules (p-value <0.002), air bronchogram (p-value <0.002), emphysema (p-value <0.002), mediastinal nodes (p-value <0.002) and distant metastasis (p-value <0.002). EGFR mutation also correlated with invasion (p-value 0.022). In ROC curves, for EGFR mutation and ALK rearrangement prediction based on mediastinal lymph nodes, the AUC was 0.661 and 0.588, respectively. The correlation between CT findings and molecular findings highlights the importance of newer radio genomic based characterization for patients with NSCLC for better diagnostic and prognostic approaches.