Multiple sclerosis, brain radiotherapy, and risk of neurotoxicity: the Mayo Clinic experience.
OBJECTIVE
The aim of this study was a retrospective assessment of neurotoxicity in patients with multiple sclerosis (MS) receiving external beam radiotherapy (EBRT) to the brain.


METHODS
We studied 15 consecutively treated patients with MS who received brain EBRT. Neurologic toxicity was assessed with the Common Toxicity Criteria v.3.0.


RESULTS
Median follow-up for the 5 living patients was 6.0 years (range, 3.3-27.4 years). No exacerbation of MS occurred in any patient during EBRT. Five patients had Grade 4 neurologic toxicity and 1 had possible Grade 5 toxicity. Kaplan-Meier estimated risk of neurotoxicity greater than Grade 4 at 5 years was 57% (95% confidence interval, 27%-82%). Toxicity occurred at 37.5 to 54.0 Gy at a median of 1.0 year (range, 0.2-4.3 years) after EBRT. Univariate analysis showed an association between opposed-field irradiation of the temporal lobes, central white matter, and brainstem and increased risk of neurotoxicity (p < 0.04). Three of 6 cases of toxicity occurred in patients treated before 1986.


CONCLUSIONS
External beam radiotherapy of the brain in patients with MS may be associated with an increased risk of neurotoxicity compared with patients without demyelinating illnesses. However, this risk is associated with treatment techniques that may not be comparable to modern, conformal radiotherapy.
Miller
Robert C
RC
Department of Radiation Oncology, Mayo Clinic, Rochester, MN55905, USA. miller.robert@mayo.edu
Lachance
Daniel H
DH
Lucchinetti
Claudia F
CF
Keegan
B Mark
BM
Gavrilova
Ralitza H
RH
Brown
Paul D
PD
Weinshenker
Brian G
BG
Rodriguez
Moses
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000528:radiation effects*; D001927:Brain Diseases / Q000209:etiology* / Q000517:prevention & control; D001932:Brain Neoplasms / Q000209:etiology / Q000517:prevention & control; D016371:Cranial Irradiation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology*; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D018570:Risk Assessment; D012307:Risk Factors