Clinical Biomarkers in Otolaryngology-Head and Neck Surgery

Exploring the Significance of Vitamin D Levels as a Biomarker in Ear Diseases: A Narrative Review

This narrative review examines the role of vitamin D as a biomarker in ear disorders, including benign paroxysmal positional vertigo (BPPV), otitis media, bell's palsy, Meniere's disease, and hearing loss. PubMed, The Cochrane Library, and Google Scholar were utilized to conduct a comprehensive literature search, and findings were combined from studies from 2014 to 2024. As highlighted in this review, there is a consistent association between vitamin D deficiency and an increased risk and recurrence of disease especially in BPPV and otitis media. Its importance as a prognostic biomarker is emphasized in Bell's palsy, where higher levels of deficiencies in vitamin D are associated with higher grades of severity on the House Brackmann grading system. Vitamin D deficiency can also lead to sensorineural hearing loss due to its receptors present in the inner ear or its effect on calcium metabolism. Serum levels of vitamin D have also been shown to influence treatment outcome of sensorineural hearing loss. The role of vitamin D in Meniere's disease is unclear as no cause has been identified for the increase in endolymphatic fluid. The findings of this review emphasize the importance of serum vitamin D as a biomarker in ear disorders and advocate for more studies to be conducted to assess the importance of optimal dosing of vitamin D for the progression and outcome of these diseases.

Malignant tumors of the external auditory canal: diagnosis, treatment, genetic landscape, biomarkers, and clinical outcome

Malignant tumors of the external auditory canal (EAC) are rare neoplasms that appear in the head and neck area. A common feature of these malignancies is their rarity, as well as their delayed diagnosis due to the appearance of non-specific symptoms that mimic various benign otologic conditions. The reported histological types of cancer of the external ear are: squamous cell carcinoma, basal cell carcinoma, malignant melanoma, Merkel cell carcinoma, angiosarcoma, adnexal carcinoma (including ceruminous adenocarcinoma and adenoid cystic carcinoma), and lymphoma (Lancet Oncol. 2005;6:411-20. doi: 10.1016/S1470-2045(05)70208-4). Several therapeutic interventions have been proposed, primarily orientated towards the cure of the patient, placing the surgical excision of the lesions at the tip of the spear. Subsequently and depending on the clinical stage and the pathological characteristics of the tumor, radiation, chemotherapy, a combination thereof, or some form of palliative treatment for particularly advanced cases, may be recommended. The aim of all the above-mentioned approaches is the complete resection of the mass with negative surgical margins along with lymph node dissection, the elimination of any residual disease or metastasis, and the improvement of survival. The anatomical complexity of the region will always remain a demanding challenge. Nevertheless, advances in the fields of ear microsurgery, imaging, radiation, molecular biology, and genomics have led to remarkable outcomes compared to the past, with a view to the patient's quality of life. Large, well-organized, and prospective studies with the participation of multiple centers in contrast to existing retrospective studies with a limited number of patients will help to establish universally accepted guidelines. The exploration of the molecular and genetic background of these cancers in conjunction with the search for new biomarkers and target molecules seems promising for providing upgraded and more personalized treatment modalities for the future.