Long-term outcomes of vestibular schwannomas treated with fractionated stereotactic radiotherapy: an institutional experience.
OBJECTIVE
We assessed clinical outcome and long-term tumor control after fractionated stereotactic radiotherapy (FSRT) for unilateral schwannoma.


METHODS
Between 1995 and 2007, 496 patients were treated with fractionated stereotactic radiotherapy at Johns Hopkins Hospital (Baltimore, MD); 385 patients had radiologic follow-up that met the inclusion criteria. The primary endpoint was treatment failure. Secondary endpoints were radiologic progression and clinical outcome. Logistic regression analysis assessed the association of age, race, tumor side, sex, and pretreatment symptoms.


RESULTS
In 11 patients (3%) treatment failed, and they required salvage (microsurgical) treatment. Radiologic progression was observed in 116 patients (30.0%), including 35 patients (9%) in whom the treatment volume more than doubled during the follow-up period, although none required surgical resection. Tumors with baseline volumes of less than 1 cm(3) were 18.02 times more likely to progress than those with tumor volumes of 1 cm(3) or greater (odds ratio, 18.02; 95% confidence interval, 4.25-76.32). Treatment-induced neurologic morbidity included 8 patients (1.6%) with new facial weakness, 12 patients (2.8%) with new trigeminal paresthesias, 4 patients (0.9%) with hydrocephalus (1 communicating and 3 obstructive), and 2 patients (0.5%) with possibly radiation-induced neoplasia.


CONCLUSIONS
Although the rate of treatment failure is low (3%), careful follow-up shows that radiologic progression occurs frequently. When reporting outcome, the "no salvage surgery needed" and "no additional treatment needed" criteria for treatment success need to be complemented by the radiologic data.
Kapoor
Sumit
S
Department of Neurosurgery, Johns Hopkins Hospital, Baltimore, MD, USA.
Batra
Sachin
S
Carson
Kathryn
K
Shuck
John
J
Kharkar
Siddharth
S
Gandhi
Rahul
R
Jackson
Juan
J
Wemmer
Jan
J
Terezakis
Stephanie
S
Shokek
Ori
O
Kleinberg
Lawrence
L
Rigamonti
Daniele
D
D000368:Aged; D018450:Disease Progression; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology; D008297:Male; D008866:Microsurgery / Q000379:methods; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D010292:Paresthesia / Q000209:etiology; D011859:Radiography; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012044:Regression Analysis; D016879:Salvage Therapy / Q000379:methods; D012737:Sex Factors; D017211:Treatment Failure; D020433:Trigeminal Nerve Diseases / Q000209:etiology; D047368:Tumor Burden