Ultra-fast confocal fluorescence microscopy for neck lymph node imaging in head and neck cancer.

OBJECTIVES: We evaluated ultra-fast confocal fluorescence microscopy (UFCM) as a new modality for pathology practice in head and neck cancer (HNC). This was assessed through an ex vivo study to estimate the accuracy, specificity, and sensitivity of interpretation of UFCM images by pathologists for the detection of metastatic lymph nodes in HNC patients undergoing sentinel lymph node biopsy or selective or complete neck dissection. MATERIALS AND METHODS: 44 patients with 32 cN0 and 12 cN+ HNC were included. The macroscopically non-invaded fresh bisected lymph nodes were stained with acridine orange and imaged with Histolog® Scanner (UFCM). Two pathologists interpreted independently the UFCM images postoperatively and gave a consensus diagnosis in case of disagreement. The gold standard was the diagnosis based on hematoxylin-eosin-saffron (HES) sections. RESULTS: 201 lymph nodes were imaged by UFCM. Thirty nodes (15 %) were invaded on final histology: 3 with micrometastases and 27 with macrometastases. The concordance rate between the pathologists on the UFCM images was 192/201 = 95.5 % and the Cohen kappa coefficient was 0.80. The accuracy of UFCM was 95.5 % (95 %CI: 91.7 %-97.9 %) with a high specificity at 98.8 % (95 %CI: 95.8 %-99.9 %) but an insufficient sensitivity at 76.7 % (95 %CI: 57.7 %-90.1 %). The three micrometastases and four of the 27 macrometastases were missed on UFCM images. CONCLUSION: The UFCM is providing promising detection values with a very good specificity and moderate sensitivity carrying room for improvement.

Intraoperative Parathyroid Gland Identification Using Autofluorescence Imaging in Thyroid Cancer Surgery with Central Neck Dissection: Impact on Post-Operative Hypocalcemia.

Hypoparathyroidism is the most frequent complication in thyroid surgery. The aim of this study was to evaluate the impact of intraoperative parathyroid gland identification, using autofluorescence imaging, on the rate of post-operative (PO) hypoparathyroidism in thyroid cancer surgery. Patients undergoing total thyroidectomy with central neck dissection from 2018 to 2022 were included. A prospective cohort of 77 patients operated on using near-infrared autofluorescence (NIRAF+) with the Fluobeam® (Fluoptics, Grenoble, France) system was compared to a retrospective cohort of 94 patients (NIR-). The main outcomes were the rate of PO hypocalcemia, with three cutoffs: corrected calcium (Cac) < 2.10 mmol/L, <2.00 mmol/L and <1.875 mmol/L, and the rate of permanent hypoparathyroidism, at 12 months. The rate of PO Cac < 2.10 mmol/L was statistically lower in the NIRAF+ group, compared to the control group (36% and 60%, p = 0.003, respectively). No statistically significant difference was observed for the other two thresholds. There was a lower rate of permanent hypoparathyroidism in the NIRAF+ group (5% vs. 14% in the control group), although not statistically significant (p = 0.07). NIRAF is a surgically non-invasive adjunct, and can improve patients' outcomes for thyroid cancer surgery by reducing post-operative temporary hypoparathyroidism. Larger prospective studies are warranted to validate our findings.

Confocal laser endomicroscopy and confocal microscopy for head and neck cancer imaging: Recent updates and future perspectives.

Confocal laser endomicroscopy (CLE) is a promising technology that provides real-time histological visualization of living tissue, described as "optical biopsy". It has been used successfully in dermatology, gastroenterology and ophthalmology for clinical diagnosis and tumor margin assessment. In addition to in vivo tissue assessment, confocal microscopy can also be used ex vivo on freshly excised or fixed tissue for intraoperative tumor margin assessment. While CLE and ex vivo confocal microscopy (EVCM) have shown promising results for the identification of head and neck cancers at cell level, several methodological issues need to be addressed before they can be widely used in routine clinical use. The present review will focus on recent advances in CLE and EVCM in the diagnosis and management of head and neck cancer and discuss remaining challenges for their clinical application.