Assessment of needle-based confocal laser endomicroscopy (nCLE) as a tool for real-time diagnosis of non-small cell lung cancer

Background: The widespread deployment of screening programs has increased the number of suspected pulmonary nodules diagnosed. The main objective of this retrospective study was to evaluate the concordance between needle-based confocal laser endomicroscopy (nCLE) image patterns and pathology reports. Methods: In this retrospective study, we reviewed all cases of endobronchial navigational bronchoscopy (ENB) performed using the nCLE system as a guide for injecting a dye marker or for biopsy of a lung nodule. All surgeries were performed at the Thoracic Surgery Department, University Hospital Nancy, France, between June and October 2023. All navigation procedures were performed under general anesthesia by a senior resident supervised by a senior surgeon, and endobronchial positioning assistance was provided by using the nCLE probe. Results: A total of 30 patients were included in this study. The median size of the suspicious lesions was 16 mm [interquartile range (IQR), 13 mm]. The average time the nCLE system was in contact with the lesion was 5 minutes (IQR, 5 minutes). In 22/30 patients, dark, enlarged pleomorphic cells were visualized, and for one patient, a mix of dark clusters and dark enlarged pleomorphic cells was visualized, leading to a diagnosis of cancer in 22/23 patients (95.6%). For five patients, dark clusters were visualized, resulting in a diagnosis of cancer in 100% of patients. Pathology was performed for 6/30 patients/21 (20%) by endobronchial biopsy and for 24 patients by surgical resection of the suspicious lesion (80%). Conclusions: By retrospectively analyzing the nCLE lung cancer criteria published by Wijmans et al. in 2019, we observed 95.6% and 100% positive diagnoses according to the images visualized during the assistance of positioning. We believe that this type of technology could be used in the future for endobronchial analysis of suspected lesions and eventually for replacing frozen section analysis. However, the diagnostic value of this system needs to be confirmed, particularly for benign lesions.