Safety and Efficacy of Fractionated
Stereotactic Radiotherapy For Acoustic Neuromas
Shearwood McClelland III M.D.1,
Bruce J. Gerbi Ph.D.2, Patrick D. Higgins Ph.D.2, James
B. Orner M.D.2, Walter
A. Hall M.D., M.B.A.1
Departments of 1Neurosurgery and 2Radiation
Oncology, University of Minnesota Medical School, Minneapolis, MN
Introduction:
The
treatment of acoustic neuromas (AN) has historically involved surgical excision
or stereotactic radiosurgery, with a relatively limited number of reports
available describing the use of fractionated stereotactic radiotherapy
(FSRT). To enhance the existing
knowledge regarding the safety and efficacy of this treatment modality, we
describe our initial experience with FSRT for AN.
Methods:
From
1999-2005, 20 patients (12F, 8M) with AN underwent FSRT. All patients were treated using the
Radionics X-Knife 4.0 3D planning system, receiving 54 Gy in 1.8 Gy daily
fractions with a prescription isodose line of 90%. Treatments were delivered stereotactically using a dedicated
Varian 6/100 linear accelerator, with immobilization achieved via the
Gill-Thomas-Cosman relocatable frame.
Median tumor size (maximum diameter) was 2.1 cm (range, 1.1-3.4 cm). Median patient age was 49.5 years, with
median follow-up of 22 months. All
patients were evaluated with pre- and postgadolinium-enhanced magnetic
resonance imaging.
Results:
Following
FSRT, local tumor control was achieved in every patient, with the treatment
well-tolerated by all patients. No
patient experienced acute complications or facial nerve weakness. Two patients experienced permanent
trigeminal nerve morbidity manifesting as facial numbness. All nine patients with preserved
hearing before treatment had hearing preservation at last follow-up.
Conclusion:
In
our series of 20 patients with AN, all had local tumor control following FSRT,
with minimal morbidity. These
results support the growing body of literature demonstrating the safety and
efficacy of FSRT in achieving local control for AN, further validating the
viability of FSRT as a treatment modality for this patient population.
Keywords:
Fractionated Stereotactic Radiotherapy, Acoustic Neuroma,
Tumor Control, Morbidity