1: Neurosurgery. 2002 Feb;50(2):270-3; discussion 273-5. Related Articles, Links
Fractionated proton beam radiotherapy for acoustic neuroma.
Bush DA, McAllister CJ, Loredo LN, Johnson WD, Slater JM, Slater JD.
Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354, USA. dbush@dominion.llumc.edu
OBJECTIVE: This study evaluated proton beam irradiation in patients with acoustic neuroma. The aim was to provide maximal local tumor control while minimizing complications such as cranial nerve injuries. METHODS: Thirty-one acoustic neuromas in 30 patients were treated with proton beam therapy from March 1991 to June 1999. The mean tumor volume was 4.3 cm(3). All patients underwent pretreatment neurological evaluation, contrast enhanced magnetic resonance imaging, and audiometric evaluation. Standard fractionated proton radiotherapy was used at daily doses of 1.8 to 2.0 cobalt Gray equivalent: patients with useful hearing before treatment (Gardner-Robertson Grade I or II) received 54.0 cobalt Gray equivalent in 30 fractions; patients without useful hearing received 60.0 cobalt Gray equivalent in 30 to 33 fractions. RESULTS: Twenty-nine of 30 patients were assessable for tumor control and cranial nerve injury. Follow-up ranged from 7 to 98 months (mean, 34 mo), during which no patients demonstrated disease progression on magnetic resonance imaging scans. Eleven patients demonstrated radiographic regression. Of the 13 patients with pretreatment Gardner-Robertson Grade I or II hearing, 4 (31%) maintained useful hearing. No transient or permanent treatment-related trigeminal or facial nerve dysfunction was observed. CONCLUSION: Fractionated proton beam therapy provided excellent local control of acoustic neuromas when treatment was administered in moderate doses. No injuries to the Vth or VIIth cranial nerves were observed. A reduction in the tumor dose is being evaluated to increase the hearing preservation rate.
PMID: 11844261 [PubMed - indexed for MEDLINE]
