Context and objective: Bilateral vestibular schwannomas are the hallmark of neurofibromatosis 2 (NF2), occurring in 95% of patients. These tumors are associated with significant morbidity due to hearing loss, tinnitus, imbalance and facial weakness. As radiosurgery and chemotherapy have been recently introduced in the treatment armamentarium in addition to surgery, a thorough evaluation of vestibular schwannoma natural history is mandatory to determine the role and timing of each treatment modality.
Methods: An exhaustive review of the literature was performed using the PubMed database concerning the natural history of tumor growth and hearing loss in NF2 patients with vestibular schwannomas.
Results: Although some aspects of vestibular schwannoma natural history remain uncertain (pattern of tumor growth, mean tumor growth rate), factors influencing growth such as age at presentation and paracrine factors are well established. Studies focusing on the natural history of hearing have highlighted different patterns of hearing loss and the possible role of intralabyrinthine tumors. The polyclonality of vestibular schwannomas in NF2 was recently unveiled, giving a new perspective to their growth mechanisms.
Conclusion: An uniform evaluation of tumor growth using volumetric evaluation and hearing with standard classifications will ensure the use of common endpoints and should improve the quality of clinical trials as well as foster comparison among studies while ensuring more consistency in decision-making.
Keywords: Conservative treatment; Croissance tumorale; Histoire naturelle; Natural history; Neurofibromatose de type 2; Neurofibromatosis type 2; Schwannome vestibulaire; Traitement conservateur; Tumor growth; Vestibular schwannoma.
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