Identifying likely malignant lymph nodes in lung cancer through endobronchial ultrasound strain elastography and multi-modality imaging in a multi-center international prospective study

To decide upon staging and concurrent treatment options in lung cancer, systematic endosonographic evaluation of lymph nodes as adjacent to the central airways and esophagus is of paramount importance. Based on imaging findings, repeated nodal sampling by endosonography guided needle aspiration is decided upon. Ultrasound strain elastography imaging might help identify likely malignant nodes, hypothesizing lower relative lymph node strain to be correlating to a higher chance of malignancy. Assessing if strain elastography can predict individual lymph node malignancy, also when further combined with available FDG-PET and nodal sizing information. A multicentric international prospective trial measuring patients with a lung cancer (suspicion) in standardized fashion (n = 5). Measurement outcomes are correlated to individual node follow-up outcome. A total of 525 lymph nodes (327 patients) are included. Receiver Operator Characteristic analysis of strain elastography measurements shows an area under the curve of 0.77. Specifying a mean nodal strain <115 (0–255) indicates malignancy with sensitivity 90%, specificity 43%, positive predictive value 60% and negative predictive value 82%. Combining available PET-CT and size information with strain elastography findings allows further risk stratification. Endobronchial ultrasound strain elastography helps predict lymph node malignancy in the work-up of lung cancer.