Ex Vivo Fluorescence Confocal Microscopy for Intraoperative Examinations of Lung Tumors as Alternative to Frozen Sections—A Proof-of-Concept Study.

Simple Summary: Intraoperative consultation is frequently used in clinical practice to establish the initial diagnosis of lung cancer when preoperative histological confirmation fails. The ability to distinguish benign and malignant lesions established frozen sections as the gold standard to guide surgical procedures. Ex vivo fluorescence confocal microscopy is a novel fully digital microimaging technique that enables timely examinations of fresh tissue without loss. The method proved to be an effective and safe method for diagnosing and subtyping lung cancer in our study and is therefore a promising alternative to frozen sections. It preserved the tissue as native material for subsequent examinations, which is an advantage in the diagnosis of small tumors and for biobanking. The acquired digital image data in cross-platform formats formed a suitable basis for telepathological procedures, e.g., second opinions by external specialists. Background: Intraoperative frozen sections (FS) are frequently used to establish the diagnosis of lung cancer when preoperative examinations are not conclusive. The downside of FS is its resource-intensive nature and the risk of tissue depletion when small lesions are assessed. Ex vivo fluorescence confocal microscopy (FCM) is a novel microimaging method for loss-free examinations of native materials. We tested its suitability for the intraoperative diagnosis of lung tumors. Methods: Samples from 59 lung resection specimens containing 45 carcinomas were examined in the FCM. The diagnostic performance in the evaluation of malignancy and histological typing of lung tumors was evaluated in comparison with FS and the final diagnosis. Results: A total of 44/45 (98%) carcinomas were correctly identified as malignant in the FCM. A total of 33/44 (75%) carcinomas were correctly subtyped, which was comparable with the results of FS and conventional histology. Our tests documented the excellent visualization of cytological features of normal tissues and tumors. Compared to FS, FCM was technically less demanding and less personnel intensive. Conclusions: The ex vivo FCM is a fast, effective, and safe method for diagnosing and subtyping lung cancer and is, therefore, a promising alternative to FS. The method preserves the tissue without loss for subsequent examinations, which is an advantage in the diagnosis of small tumors and for biobanking. [ABSTRACT FROM AUTHOR]