acriflavine and Squamous-Cell-Carcinoma-of-Head-and-Neck

Confocal laser endomicroscopy (CLE) is a technology that enables microscopic visualization of lesions in real-time (optical biopsy) and has been successfully applied for clinical use in gastroenterology. Recently, it was also introduced for head and neck squamous cell carcinoma (HNSCC) diagnostics. We previously designed a self-made CLE, which can provide bichrome images, with topical contrast agents that are safe for use in patients. Herein, we report findings of a pilot study using our self-made CLE to image pairs of normal and cancerous tissues. This study aimed to characterize the features of HNSCC compared with normal mucosa and to establish a methodology of in vivo real-time optical biopsy of HNSCCs.. HNSCC tissues were acquired from 10 patients who underwent surgical resection. Dissected specimens were first evaluated for their auto-fluorescence spectral profiles with 473 nm laser excitation and further optical observation. While obtaining the image, auto-fluorescence spectrum and intensity of the reflectance fluorescent signals were measured in real-time by a spectrometer. Subsequently, acriflavine was applied to the specimen to fluorescently label the nuclei and observe the difference between normal and cancerous tissues with 473 nm laser excitation. Finally, double staining with acriflavine and edible Food Red No.106 was performed to observe both nuclei and the cytoplasm of normal and cancerous tissues at 473 nm and 561 nm laser excitation.. Lower signals were detected from auto-fluorescence images of cancer tissues than normal tissues with 473 nm laser excitation. After acriflavine application, there was a clear difference between cancer and normal mucosa in the uniformity of nuclear size and shape. In normal mucosa, cells were arranged in an orderly manner, with each cell resembling a frog's egg. By contrast, in cancer tissues, the cell density was higher, and the cellular arrangement was less orderly. Using both acriflavine and Food Red No.106, images became more vivid, but more complicated because red dye staining of the cytoplasm emerged as fluorescence at different wavelengths.. Real-time in vivo imaging using the newly developed CLE and conditions may be used to distinguish cancer tissue from normal mucosa without invasive biopsy.

Topics: Acriflavine; Aged; Aged, 80 and over; Biopsy; Endoscopy; Female; Fluorescent Dyes; Head and Neck Neoplasms; Humans; Intravital Microscopy; Laryngeal Neoplasms; Male; Microscopy, Confocal; Middle Aged; Mouth Neoplasms; Optical Imaging; Pharyngeal Neoplasms; Pilot Projects; Squamous Cell Carcinoma of Head and Neck

Confocal laser endomicroscopy (CLE) is an imaging technique that uses miniaturized fiberoptic probes to allow real-time histological imaging of human tissue. An application of CLE in otorhinolaryngology has hardly been investigated so far. In our study, we analyzed the applicability of CLE to visualize cancerous and healthy tissue of the head and neck region. Formalin-fixed tissue specimens from 135 head and neck squamous cell carcinoma (HNSCC) patients and 50 healthy controls were investigated using CLE with and without topical application of acriflavine. Four head and neck surgeons, four pathologists, and four laymen evaluated the CLE images of the HNSCC cases regarding the tumor localization and its border to healthy tissue. The tumor localization and the tumor border were correctly identified in 97 % by the pathologists, 85 % by the head and neck surgeons, and 70 % by the laymen. The main difference in evaluation results was seen in the correct identification of the tumor site (p < 0.05), while there was no significant difference in the identification of the tumor border. CLE is a valuable tool for real-time histological imaging of HNSCCs. It can help to visualize the tumor border and, thereby, facilitate a more precise tumor surgery.

Topics: Acriflavine; Adult; Aged; Carcinoma, Squamous Cell; Female; Fluorescent Dyes; Head and Neck Neoplasms; Humans; Male; Microscopy, Confocal; Optical Imaging; Squamous Cell Carcinoma of Head and Neck