Acoustic Neuroma: Treatment or Observation?

Abstract

Should a newly diagnosed schwannoma of the vestibular nerve be observed, surgically removed, or irradiated? This question and others about this type of tumor, also known as acoustic neuroma, were of interest to the more than 600 participants at the European Skull Base Congress, which took place in Rotterdam in April 2009. Sven-Eric Stangerup of Gentofte University, Copenhagen, reported on studies of the incidence of these tumors and their natural course without treatment. The increased incidence in Denmark over the last 26 years, leading to the current figure of about 1 per 100 000 persons per year, can be accounted for by the more widespread use of magnetic resonance imaging (MRI). Interestingly, however, the mean age of affected patients at the time of diagnosis has not become any lower. A proposed explanation for this observation was that MRI is being increasingly performed in the elderly as well. By incorporating data from practically all affected patients in Denmark in a single database, Stangerup and his team were able to show that, after an average of three and a half years of observation, tumor growth was seen in 17% of small, intracanalicular schwannomas and in 29% of the tumors that extended into the cerebellopontine angle. After a longer period of observation lasting five years, 45% of the tumors that were originally confined to the internal auditory canal were found to have grown.