Twenty years' experience in the treatment of acoustic neuromas with fractionated radiotherapy: a review of 45 cases.
OBJECTIVE
To evaluate very long-term results of fractionated radiotherapy (FRT) of acoustic neuromas (AN).


METHODS
From January 1986 to January 2004, FRT was performed in 45 consecutive patients (46 AN). Indications were as follows: poor general condition contraindicating surgery, hearing preservation in bilateral neuromas, partial resection, nonsurgical recurrence. A 3-field to 5-field technique with static beams was used. A mean total dose of 51 Gy was given (1.80 Gy/fraction). The median tumor diameter was 31 mm (range, 11-55 mm). The median follow-up from FRT was 80 months (range, 4-227 months).


RESULTS
The particularity of our series consists of a very long-term follow-up of FRT given to selected patients. Nineteen patients died, two with progressive disease, and 17 from non-AN causes. A serviceable level of hearing was preserved in 7/9 hearing patients. No patient had facial or trigeminal neuropathy. Tumor shrinkage was observed in 27 (59%) and stable disease in 16 (35%). Tumor progression occurred in three patients, 12 to 15 months after FRT. Two additional tumors recurred after shrinkage 20 and 216 months after treatment and were operated on. Actuarial local tumor control rates at 5 and 15 years were 86%. For the patient who had a tumor recurrence at 216 months, histologic examination documented transformation to a low-grade malignant peripheral nerve sheath tumor.


CONCLUSIONS
Very long-term efficacy of FRT is well documented in this series. However, our results suggest that malignant transformation can occur many years after FRT so we advocate caution when using this treatment for young patients.
Maire
Jean-Philippe
JP
Department of Oncologie Médicale and Radiothérapie, Hôpital Saint-André, Bordeaux, France. jean-philippe.maire@chu-bordeaux.fr
Huchet
Aymeri
A
Milbeo
Yann
Y
Darrouzet
Vincent
V
Causse
Nicole
N
Célérier
Denis
D
Liguoro
Dominique
D
Bébéar
Jean-Pierre
JP
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome