Proton beam radiosurgery for @entity5513 : XXXX control and @entity129 .

@entity1 @entity129 @entity5513 @entity548 @entity1276 @entity5 @entity16 @entity2103
OBJECTIVE: We sought to determine the @entity5 control rate and cranial nerve function outcomes in @entity1 with @entity5513 who were treated with proton beam stereotactic radiosurgery. METHODS: Between November 1992 and August 2000, 88 @entity1 with @entity5513 were treated at the Harvard Cyclotron Laboratory with proton beam stereotactic radiosurgery in which two to four convergent fixed beams of 160-MeV protons were applied. The median transverse diameter was 16 mm (range, 2.5-35 mm), and the median @entity5 volume was 1.4 cm(3) (range, 0.1-15.9 cm(3)). Surgical resection had been performed previously in 15 @entity1 (17%). @entity2103 (House-Brackmann Grade 1) and trigeminal nerve function were normal in 79 @entity1 (89.8%). Eight @entity1 (9%) had good or excellent hearing (Gardner-Robertson [GR] Grade 1), and 13 @entity1 (15%) had serviceable hearing (GR Grade 2). A median dose of 12 cobalt Gray equivalents (range, 10-18 cobalt Gray equivalents) was prescribed to the 70 to 108% isodose lines (median, 70%). The median follow-up period was 38.7 months (range, 12-102.6 mo). RESULTS: The actuarial 2- and 5-year @entity5 control rates were 95.3% (95% confidence interval [CI], 90.9-99.9%) and 93.6% (95% CI, 88.3-99.3%). Salvage radiosurgery was performed in one @entity1 32.5 months after treatment, and a craniotomy was required 19.1 months after treatment in another @entity1 with @entity548 in the vicinity of a stable @entity5 . Three @entity1 (3.4%) underwent shunting for @entity1276 , and a subsequent partial resection was performed in one of these @entity1 . The actuarial 5-year cumulative radiological reduction rate was 94.7% (95% CI, 81.2-98.3%). Of the 21 @entity1 (24%) with functional hearing (GR Grade 1 or 2), 7 (33.3%) retained serviceable hearing ability (GR Grade 2). Actuarial 5-year normal facial and trigeminal nerve function preservation rates were 91.1% (95% CI, 85-97.6%) and 89.4% (95% CI, 82-96.7%). Univariate analysis revealed that prescribed dose (P = 0.005), maximum dose (P = 0.006), and the inhomogeneity coefficient (P = 0.03) were associated with a significant risk of long-term @entity16 . No other @entity129 or @entity5 relapses were observed. CONCLUSION: Proton beam stereotactic radiosurgery has been shown to be an effective means of @entity5 control. A high radiological response rate was observed. Excellent facial and trigeminal nerve function preservation rates were achieved. A reduced prescribed dose is associated with a significant @entity16 .
