Fractionated stereotactic radiotherapy for acoustic neuromas: preservation of function versus size

For larger acoustic neuromas the preservation of cranial nerve function following radiosurgery remains a challenge. Fractionated stereotactic radiotherapy (FSR) for acoustic neuromas offers both higher total tumour dose (Gy) and potential sparing of the facial motor, sensory and auditory cranial nerves. Eighty consecutive patients (45 M, 35 F) (age 56.8 +/- 1.7 years) received FSR for AN and have a median follow up of 1.1 years. A prospective schedule permitted increased fractionation vs. size. For FSR 70 patients having AN < 3.0 cm in diameter had 5 daily fractions of 5Gy (25Gy total) and 10 patients having AN greater than or equal to3cm had 10 daily fractions of 3Gy (30Gy total). Ail treatments were prescribed to the 80% isodose and given via the dedicated 10 MeV accelerator, For both the larger and smaller AN, the percentage decrease in volume was similar. No turnout increased in size, no patient developed facial weakness and hearing was preserved. Using size-dependent fractionation, FSR may result in both turnout control and preservation of normal cranial nerve functions for both large and small AN. (C) 2002 Published by Elsevier Science Ltd.