Underwent Repeat Stereotactic Radiosurgery Research Articles

Repeat Radiosurgery for Sporadic Vestibular Schwannoma After Primary Radiosurgical Failure: An International Multi-institutional Investigation.

To describe outcomes of patients with sporadic vestibular schwannoma (VS) who underwent repeat stereotactic radiosurgery (SRS) after primary SRS failure. Multi-institutional historical cohort study. Five tertiary care referral centers. Adults ≥18 years old with sporadic VS. Primary and repeat treatment with SRS. Microsurgery-free survival after repeat SRS. Across institutions, 32 patients underwent repeat SRS after primary SRS. Most patients (74%) had tumors with cerebellopontine angle extension at primary SRS (median size, 13.5 mm [interquartile range, 7.5-18.8] mm). After primary SRS, patients underwent repeat SRS at a median of 4.8 years (interquartile range, 3.2-5.7 yr). For treatment modality, 30 (94%) patients received gamma knife for primary treatment and 31 (97%) patients received gamma knife as their repeat treatment. Median tumor volume increased from 0.970 cm3 at primary SRS to 2.200 cm3 at repeat SRS. Facial nerve function worsened in two patients after primary SRS and in two patients after repeat SRS. There were no instances of intracranial complications after repeat SRS. Microsurgery-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after repeat SRS were 97% (90-100%, 24), 84% (71-100%, 13), and 68% (48-96%, 6), respectively. There was one occurrence of malignancy diagnosed after repeat radiosurgery. Overall, repeat SRS for sporadic VS has comparable risk profile, but lower rates of tumor control, compared with primary SRS.

Stereotactic Radiosurgery as an Effective and Safe Treatment Modality in Central Nervous System Lymphoma, a Single Institution Experience

CNS lymphoma (CNSL) is an aggressive liquid cancer with the potential for rapid progression. Standard treatment regimens for CNSL have included chemotherapy and whole brain radiotherapy (WBRT). WBRT carries a high risk of leukoencephalopathy (LE) manifesting as cognitive decline and is identifiable on brain MRI as fluid attenuation inversion recovery (FLAIR) changes. Stereotactic radiosurgery (SRS) can precisely deliver higher biologically effective doses of radiation, while minimizing damage to surrounding healthy brain tissue. SRS offers enhanced local control in CNSL with minimal risk of LE. Patients undergoing SRS at an NCI-designated comprehensive cancer center from 2000 to 2022 were prospectively enrolled into a database. Twenty-nine consecutive patients diagnosed with relapsed primary CNSL (59%) or secondary CNSL (41%) were included in this study. Median age at diagnosis was 70 (range 23-91) years and 14 were female. Follow up MRI imaging was obtained at 1-, 3-, 6- and 12-months post-procedure. Measurement of tumor volumes was performed at treatment and each subsequent follow-up by image co-registration and tumor segmentation. Pre and post SRS brain MRIs were independently reviewed by a neuro-radiologist to score the grade of LE for each patient. Progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier analyses and Log-rank tests using statistical software. Twenty-nine patients treated for 50 tumors were studied. Twenty-four patients were treated for a single tumor, and 5 for multiple tumors. Six patients underwent repeat SRS treatment for 10 out-of-field recurrences and 1 patient for an in-field recurrence. Of the 35 SRS procedures performed, 32 (88%) were single session delivery and 3 were hypofractionated. Stereotactic immobilization was achieved with frame (57%) or thermoplastic mask (43%). Median prescribed dose was 14 Gy (range 10-21) to the 50% isodose line (range 40-100). Median coverage, selectivity and gradient index were 0.97, 0.69, and 2.9 respectively. Median follow-up time was 4.5 months (range 0.5-64). Twenty-six (52%) tumors completely responded to treatment with no residual enhancement, while the rest decreased in volume. No tumor failed to respond to treatment. Median time to best volumetric response was achieved in 2.9 months (range 1-6.1) and median volume of best response was zero cc (range 0-1.19). The median OS of the cohort was 7.0 months (95% CI 5.1-8.9), while the median PFS was 5.0 months (95% CI 1.2-8.8). Median score of LE was zero, and only one patient experienced grade 3 MRI FLAIR changes. With a median time to response of 2.9 months, a 100% initial response rate and a single in-field failure, our analysis demonstrates a rapid and effective response of CNSL to SRS. Distant failures were controlled with repeat SRS. The absence of LE in the treated patients provides further evidence for safety and tolerability of SRS in CNSL.

Stereotactic radiosurgery for intermediate- and high-grade arteriovenous malformations: outcomes stratified by the supplemented Spetzler-Martin grading system.

The supplemented Spetzler-Martin (Supp-SM) grading system was developed to improve the predictive accuracy of surgical risk for patients with brain arteriovenous malformations (AVMs). The aim of this study was to apply the Supp-SM grading system to patients having stereotactic radiosurgery (SRS) for Spetzler-Martin (SM) intermediate- (grade III) or high-grade (grade IV-V) AVMs to enable comparison with published microsurgical series. In 219 patients who underwent SRS during the period from 1990 to 2016, the Supp-SM grade was calculated for SM grade III (n = 154) or SM grade IV-V (n = 65) AVMs. The Supp-SM grades in these patients were 4 (n = 14, 6%), 5 (n = 36, 16%), 6 (n = 67, 31%), 7 (n = 76, 35%), and 8-9 (n = 26, 12%). Sixty patients (27%) had deep AVMs (basal ganglia, thalamus, or brainstem). Thirty-nine patients (18%) had volume-staged SRS; 41 patients (19%) underwent repeat SRS. The median follow-up period was 69 months for SM grade III AVMs and 113 months for SM grade IV-V AVMs. AVM obliteration was confirmed in 163 patients (74%) at a median of 38 months after initial SRS. The obliteration rates at 4 and 8 years were 59% and 76%, respectively. Thirty-one patients (14%) had post-SRS deficits from hemorrhage (n = 7, 3%) or radiation injury (n = 24, 11%). Six patients (3%) died after SRS (hemorrhage, n = 5; radiation injury, n = 1). The rates of neurological decline or death at 4 and 8 years were 11% and 18%, respectively. Factors predictive of nonobliteration were deep location (HR 0.57, 95% CI 0.39-0.82, p = 0.003) and increasing AVM volume (HR 0.96, 95% CI 0.93-0.99, p = 0.002). Increasing AVM volume was the only factor associated with neurological decline (HR 1.05, 95% CI 1.02-1.08, p = 0.002). The Supp-SM grading score did not correlate with either obliteration (HR 0.94, 95% CI 0.82-1.09, p = 0.43) or neurological decline (HR 1.15, 95% CI 0.84-1.56, p = 0.38). The Supp-SM grading system was not predictive of outcomes after SRS of intermediate- or high-grade AVM. In a cohort that included a high percentage (47%) of "inoperable" AVMs according to Supp-SM grade (≥ 7), most patients had obliteration after SRS, although there was a high risk of neurological decline.

Repeat stereotactic radiosurgery for cerebral arteriovenous malformations.

The purpose of this retrospective, single-institution study was to evaluate radiological and clinical outcomes of patients managed with repeat stereotactic radiosurgery (SRS) for residual cerebral arteriovenous malformation (AVM) after prior SRS. The authors evaluated the clinical and radiological outcomes of consecutive patients treated with repeat single-session SRS for a residual brain AVM from 1989 to 2021. In total, 170 patients underwent repeat SRS for AVM (90 [52.9%] females; median [interquartile range] age at the first SRS procedure 28 [21.5] years; median [interquartile range] age at the second SRS procedure 32 [22.5] years). After repeat SRS, the actuarial 3-, 5-, and 10-year AVM obliteration rates were 37.6%, 57.3%, and 80.9%, respectively. Higher obliteration rates were associated with margin dose ≥ 19 Gy (p = 0.001). After the second SRS procedure, hemorrhage occurred in 8.2% of patients and was lethal in 1 patient. The risk factors of intracranial hemorrhage were age < 18 years (p = 0.03) and residual AVM diameter > 20 mm (p = 0.004). Lower obliteration rates were noted in patients with residual AVM diameter > 20 mm (p = 0.04) and those < 18 years of age (p = 0.04). Asymptomatic, symptomatic, and permanent radiation-induced changes (RICs) after the second SRS procedure occurred in 25.9%, 8.8%, and 5.3% of patients, respectively, and were associated with RIC after the first SRS procedure (p = 0.006). There was 1 case of a radiation-induced meningioma 12 years after SRS. Repeat SRS is a reasonable therapeutic option, in particular for patients with residual AVM. Repeat SRS was associated with more favorable outcomes in adult patients and those with residual AVM smaller than 20 mm in maximum diameter. To increase the rate of residual AVM obliteration, a prescription dose ≥ 19 Gy should ideally be used for repeat SRS.

Frameless Stereotactic Radiosurgery on the Gamma Knife Icon: Early Experience From 100 Patients.

The Gamma Knife (GK) Icon (Elekta AB) uses a cone-beam computed tomography (CBCT) scanner and an infrared camera system to support the delivery of frameless stereotactic radiosurgery (SRS). There are limited data on patients treated with frameless GK radiosurgery (GKRS). To describe the early experience, process, technical details, and short-term outcomes with frameless GKRS at our institution. We reviewed our patient selection and described the workflow in detail, including image acquisition, treatment planning, mask-based immobilization, stereotactic CBCT localization, registration, treatment, and intrafraction monitoring. Because of the short interval of follow-up, we provide crude rates of local control. Data from 100 patients are reported. Median age is 67 yr old. 56 patients were treated definitively, 21 postoperatively, and 23 had salvage GKRS for recurrence after surgery. Forty-two patients had brain metastases, 26 meningiomas, 16 vestibular schwannomas, 9 high-grade gliomas, and 7 other histologies. Median doses to metastases were 20 Gy in 1 fraction (range: 14-21), 24 Gy in 3 fractions (range: 19.5-27), and 25 Gy in 5 fractions (range: 25-30 Gy). Thirteen patients underwent repeat SRS to the same area. Median treatment time was 17.7 min (range: 5.8-61.7). We found an improvement in our workflow and a greater number of patients eligible for GKRS because of the ability to fractionate treatments. We report a large cohort of consecutive patients treated with frameless GKRS. We look forward to studies with longer follow-up to provide valuable data on clinical outcomes and to further our understanding of the radiobiology of hypofractionation in the brain.

Applicability and limitations of a recently-proposed prognostic grading metric, initial brain metastasis velocity, for brain metastasis patients undergoing stereotactic radiosurgery.

This study, based on our brain metastasis (BM) patients undergoing stereotactic radiosurgery (SRS) procedures, aimed to validate whether the recently-proposed prognostic grading system, initial brain metastasis velocity (iBMV, scoring the cumulative number of BMs at the time of SRS divided by time [years] since the initial primary cancer diagnosis), is generally applicable. This was an institutional review board-approved, retrospective cohort study using our prospectively accumulated database including 3498 patients who underwent SRS for BMs during the 19.5-year-period between July, 1998 and December, 2017. We excluded four lost to follow-up, 24 for whom the day of primary cancer diagnosis was not available, 665 with synchronous presentation and 651 with pre-SRS radiotherapy and/or surgery, ultimately studying 2150 patients. Patients were categorized into two classes by iBMV scores, i.e., < 2.00 and ≥ 2.00. In a multivariable model, iBMV was directly associated with a higher risk of death (p < 0.0001). The median survival time of patients with iBMV scores < 2.00, 10.0 (95% CI; 9.2-10.9) months, was longer than that of patients with iBMV scores ≥ 2.00, 6.3 (5.6-6.7) months, showing a significant difference between the two groups (HR 1.599, 95% CI 1.458-1.753, p < 0.0001). The same results were obtained in patients with non-small cell lung, breast, kidney or other cancers. Among 608 patients who underwent repeat SRS for newly-developed BMs, iBMV score categories correlated well with brain metastasis velocity risk groups (p < 0.0001). Our present results support the validity of iBMV for predicting survival after SRS.

Gamma Knife Radiosurgery for Bilateral Trigeminal Neuralgia

Bilateral trigeminal neuralgia (BTN) makes up a small subset of patients with trigeminal neuralgia. These patients have a higher incidence of familial TN and multiple sclerosis and their management is controversial. Here we report a large single institution retrospective cohort of patients with BTN treated with stereotactic radiosurgery (SRS). SRS database review identified 78 nerves in 52 patients with BTN who underwent at least one SRS between 1999 and 2017. Background history, demographics, treatment outcomes, complications, and dosimetric data were obtained by retrospective chart review. Long-term follow-up was obtained by a standardized telephone interview performed by a physician. Successful treatment was defined as BNI IIIb or better pain relief. Time-to-failure outcomes were estimated by the Kaplan-Meier method. Hazard ratios (HR) associated with patient and treatment-related variables for time-to-failure outcomes were estimated by Cox proportional hazards methods. Of the 78 individual nerves treated with a first SRS, 77 had sufficient follow up data to determine BNI pain score outcomes. Sixty-seven of the 77 nerves (87%) achieved ≥ BNI IIIb pain relief, with 34 (44%) achieving BNI I pain relief. The median time to BNI IIIb pain relief was 3.5 weeks. At a median follow-up of 3.4 years, the median duration of ≥ BNI IIIb pain relief was 2.5 years. The estimated 1, 3, and 5-year rates of ≥ BNI IIIb pain relief were 71%, 43%, and 32%. Post-SRS facial numbness was seen in 33 (43%) cases, with five (6.5%) being bothersome. Two (2.6%) cases of anesthesia dolorosa (AD) and five (6.4%) cases of corneal numbness were reported. SRS with a maximal post procedure BNI of IIIb were more likely to experience pain relapse than those who achieved BNI I relief (HR 2.55, p = 0.04), as were those who had a history of prior ipsilateral microvascular decompression (MVD) (HR 2.64, p = 0.03). Left sided pain was more likely to relapse than right sided (HR 2.22, p = 0.02). Twenty-two nerves underwent repeat SRS for recurrent pain, of which 20 had sufficient follow up to determine BNI pain score outcomes. Of these, 19 (95%) had ≥ BNI IIIb pain relief, with 8 (40%) reaching BNI I relief. The median time to BNI IIIb pain relief was 8 weeks. At a median follow-up of 4.1 years, the median duration of BNI IIIb or better pain relief was 8 years, with estimated 1, 3, and 5-year rates of pain relief of 89%, 62%, and 62% respectively. Eleven (55%) experienced facial numbness after repeat SRS with four (20%) being bothersome. One case (5.6%) of corneal numbness and zero cases of AD were reported after repeat SRS. SRS is an effective, well-tolerated treatment modality for patients with BTN. Patients with prior MVD or SRS that resulted in maximal pain relief of BNI IIIb are more likely to experience pain relapse than those who achieved BNI I relief. Repeat SRS appears to have greater efficacy and durability than initial SRS, and despite increased bothersome facial numbness remains well tolerated.

Long-term pain outcomes for recurrent idiopathic trigeminal neuralgia after stereotactic radiosurgery: a prospective comparison of first-time microvascular decompression and repeat stereotactic radiosurgery.

Microvascular decompression (MVD) and stereotactic radiosurgery (SRS) are common surgical treatments for trigeminal neuralgia (TN). Many patients who receive SRS have pain recurrence; the ideal second intervention is unknown. The authors directly compared pain outcomes after MVD and repeat SRS in a population of patients in whom SRS failed as their first-line procedure for TN, and they identified predictors of pain control. The authors reviewed a prospectively collected database of patients undergoing surgery for TN between 1997 and 2014 at the University of California, San Francisco (UCSF). Standardized data collection focused on preoperative clinical characteristics, surgical characteristics, and postoperative outcomes. Patients with typical type 1, idiopathic TN with ≥ 1 year of follow-up were included. In total, 168 patients underwent SRS as their first procedure. Of these patients, 90 had residual or recurrent pain. Thirty of these patients underwent a second procedure at UCSF and had ≥ 1 year of follow-up; 15 underwent first-time MVD and 15 underwent repeat SRS. Patients undergoing MVD were younger than those receiving repeat SRS and were more likely to receive ≥ 80 Gy during the initial SRS. The average follow-up was 44.9 ± 33.6 months for MVD and 48.3 ± 45.3 months for SRS. All patients achieved complete pain freedom without medication at some point during their follow-up. At last follow-up, 80% of MVD-treated patients and 33.3% of SRS-treated patients had a favorable outcome, defined as Barrow Neurological Institute Pain Intensity scores of I-IIIa (p < 0.05). Percentages of patients with favorable outcome at 1 and 5 years were 86% and 75% for the MVD cohort and 73% and 27% for the SRS cohort, respectively (p < 0.05). Multivariate Cox proportional hazards analysis demonstrated that performing MVD was statistically significantly associated with favorable outcome (HR 0.12, 95% CI 0.02-0.60, p < 0.01). There were no statistically significant predictors of favorable outcome in the MVD cohort; however, the presence of sensory changes after repeat SRS was associated with pain relief (p < 0.01). Patients who received MVD after failed SRS had a longer duration of favorable outcome compared to those who received repeat SRS; however, both modalities are safe and effective. The presence of post-SRS sensory changes was predictive of a favorable pain outcome in the SRS cohort.

Repeat Stereotactic Radiosurgery for Recurred Metastatic Brain Tumors.

ObjectiveWe investigated the outcomes of repeat stereotactic radiosurgery (SRS) for metastatic brain tumors that locally recurred despite previous SRS, focusing on the tumor control. MethodsA total of 114 patients with 176 locally recurring metastatic brain tumors underwent repeat SRS after previous SRS. The mean age was 59.4 years (range, 33 to 85), and there were 68 male and 46 female patients. The primary cancer types were non-small cell lung cancer (n=67), small cell lung cancer (n=12), gastrointestinal tract cancer (n=15), breast cancer (n=10), and others (n=10). The number of patients with a single recurring metastasis was 95 (79.8%), and another 19 had multiple recurrences. At the time of the repeat SRS, the mean volume of the locally recurring tumors was 5.94 mL (range, 0.42 to 29.94). We prescribed a mean margin dose of 17.04 Gy (range, 12 to 24) to the isodose line at the tumor border primarily using a 50% isodose line. ResultsAfter the repeat SRS, we obtained clinical and magnetic resonance imaging follow-up data for 84 patients (73.7%) with a total of 108 tumors. The tumor control rate was 53.5% (58 of the 108), and the median and mean progression-free survival (PFS) periods were 246 and 383 days, respectively. The prognostic factors that were significantly related to better tumor control were prescription radiation dose of 16 Gy (p=0.000) and tumor volume less than both 4 mL (p=0.001) and 10 mL at the repeat SRS (p=0.008). The overall survival (OS) periods for all 114 patients after repeat SRS varied from 1 to 56 months, and median and mean OS periods were 229 and 404 days after the repeat SRS, respectively. The main cause of death was systemic problems including pulmonary dysfunction (n=58, 51%), and the identified direct or suspected brain-related death rate was around 20%. ConclusionThe tumor control following repeat SRS for locally recurring metastatic brain tumors after a previous SRS is relatively lower than that for primary SRS. However, both low tumor volume and high prescription radiation dose were significantly related to the tumor control following repeat SRS for these tumors after previous SRS, which is a general understanding of primary SRS for metastatic brain tumors.

Stereotactic radiosurgery for jugular foramen schwannomas: an international multicenter study.

For some jugular foramen schwannomas (JFSs), complete resection is possible but may be associated with significant morbidity. Stereotactic radiosurgery (SRS) is a minimally invasive alternative or adjunct to microsurgery for JFSs. The authors reviewed clinical and imaging outcomes of SRS for patients with these tumors. Nine participating centers of the International Gamma Knife Research Foundation identified 92 patients who underwent SRS between 1990 and 2013. Forty-one patients had prior subtotal microsurgical resection. The median interval between previous surgery and SRS was 15 months (range 0.5-144 months). Eighty-four patients had preexisting cranial nerve (CN) symptoms and signs. The median tumor volume was 4.1 cm3 (range 0.8-22.6 cm3), and the median margin dose was 12.5 Gy (range 10-18 Gy). Patients with neurofibromatosis were excluded from this study. The median follow-up was 51 months (range 6-266 months). Tumors regressed in 47 patients, remained stable in 33, and progressed in 12. The progression-free survival (PFS) was 93% at 3 years, 87% at 5 years, and 82% at 10 years. In the entire series, only a dumbbell shape (extension extracranially via the jugular foramen) was significantly associated with worse PFS. In the group of patients without prior microsurgery (n = 51), factors associated with better PFS included tumor volume < 6 cm3 (p = 0.037) and non-dumbbell-shaped tumors (p = 0.015). Preexisting cranial neuropathies improved in 27 patients, remained stable in 51, and worsened in 14. The CN function improved after SRS in 12% of patients at 1 year, 24% at 2 years, 27% at 3 years, and 32% at 5 years. Symptomatic adverse radiation effects occurred in 7 patients at a median of 7 months after SRS (range 5-38 months). Six patients underwent repeat SRS at a median of 64 months (range 44-134 months). Four patients underwent resection at a median of 14 months after SRS (range 8-30 months). Stereotactic radiosurgery proved to be a safe and effective primary or adjuvant management approach for JFSs. Long-term tumor control rates and stability or improvement in CN function were confirmed.

Stereotactic radiosurgery for brain metastases from primary head and neck carcinomas: a retrospective analysis.

Patients with head and neck malignancies commonly develop metastatic disease, yet rarely do these carcinomas metastasize to the brain. Stereotactic radiosurgery (SRS) is routinely employed to treat brain metastases (BM). This study was undertaken to examine the efficacy of SRS for BM from primary head and neck carcinomas. From 2000 to 2016, a total of 19 patients with 38 lesions were retrospectively identified. All patients presented with a primary head and neck malignancy and subsequently developed metastatic disease to the brain treated with SRS at our institution. Actuarial rates for overall survival (OS), local control (LC) and distant brain metastases (DBM) were calculated using Kaplan-Meier estimates. Median follow up was 6.8 months and median survival was 15.8 months. Eleven lesions received post-operative SRS to a surgical cavity and 27 lesions received definitive SRS to a metastasis. The median dose prescribed was 18Gy. One-year actuarial rate for LC was 77.3% (95% confidence interval [CI] 44-92%) while 1year and 2 year rates of OS were 52.9% (CI 28-73%) and 31.7% (CI 11-55%) respectively. The median time to develop DBM was 8.4 months. Three patients (16%) underwent repeat SRS following development of new BM and three patients (16%) underwent salvage whole brain radiotherapy (WBRT). SRS may be utilized in the treatment of patients with primary head and neck malignancies metastasized to the brain with high efficacy. Patients with well-controlled systemic disease and good performance status may benefit the most from definitive SRS while avoiding WBRT.

Repeat Stereotactic Radiosurgery for Locally Recurrent Brain Metastases.

The outcomes of repeat stereotactic radiosurgery (SRS) after failure of previous SRS are not well established. We report our overall experience using SRS for the retreatment of locally recurrent brain metastases. Patients with brain metastases diagnosed between 2003 and 2015 who underwent repeat SRS for local tumor progression following prior SRS were identified. Rates of local control, radiation necrosis, and overall survival were analyzed. Factors affecting local failure and radiation necrosis were assessed by chi-square test. Twenty-four lesions in 22 patients underwent repeat SRS in a single fraction. Median age was 59 years. The median SRS-1 dose was 18 Gy, and the median SRS-2 dose was 15.5 Gy. The median SRS-1 target volume was 2.25 cm3, and the median SRS-2 target volume was 3.30 cm3. The median follow-up from SRS-2 was 8.8 months. The actuarial local controls for SRS-2 were 94.1% and 61.1% at 6 and 12 months, respectively. The incidences of actuarial radiation necrosis were 9.2% and 9.2% at 6 and 12 months, respectively. Volume of tumor >4 cm3 correlated with increased risk of local failure (P= 0.006) with no local failures recorded with volumes ≤4 cm3. SRS-2 dose, cumulative SRS dose, receipt of whole brain radiotherapy, and use of SRS-2 as boost after surgery did not correlate with local failure or radiation necrosis. Median overall survival after SRS-2 was 8.78 months. Repeat SRS is feasible for select patients, particularly for those with tumor volume ≤4 cm3. Further evaluation is needed to establish the most appropriate treatment doses and volumes for this approach.

Stereotactic radiosurgery for idiopathic glossopharyngeal neuralgia: an international multicenter study

OBJECTIVE The goal of this study was to evaluate the outcomes of Gamma Knife stereotactic radiosurgery (SRS) when used for patients with intractable idiopathic glossopharyngeal neuralgia. METHODS Six participating centers of the International Gamma Knife Research Foundation identified 22 patients who underwent SRS for intractable glossopharyngeal neuralgia between 1998 and 2015. The median patient age was 60 years (range 34-83 years). The median duration of symptoms before SRS was 46 months (range 1-240 months). Three patients had unsuccessful prior surgical procedures, including microvascular decompression (MVD) (n = 2) and balloon compression (n = 1). The radiosurgical target was the glossopharyngeal meatus. The median maximum dose was 80 Gy. RESULTS The median follow-up was 45 months after SRS (range 6-120 months). Twelve patients (55%) had < 4 years of follow-up. Thirteen patients (59%) had initial complete pain relief at a median of 12 days after SRS (range 1-60 days). Three patients (14%) had partial pain relief at a median of 70 days after SRS (range 60-90 days). Six patients (27%) had no pain relief. Among 16 patients with initial pain relief, 5 maintained complete pain relief without medication (Barrow Neurological Institute [BNI] pain intensity score Grade I), 1 maintained occasional pain relief without medication (BNI Grade II), 3 maintained complete pain relief with medication (BNI Grade IIIb), and 7 patients had pain recurrence at a median of 20 months after SRS (range 6-120 months). The rates of maintenance of adequate pain relief (BNI Grades I-IIIb) were 63% at 1 year, 49% at 2 years, 38% at 3 years, 38% at 5 years, and 28% at 7 years. When 7 patients without pain recurrence within 4 years of follow-up were excluded, the rates of maintenance of adequate pain relief were 38% at 5 years and 28% at 7 years. Ten patients required additional procedures (MVD, n = 4; repeat SRS, n = 5; glossopharyngeal nerve block, n = 1). Four of 5 patients who underwent repeat SRS maintained pain relief (BNI Grade I, n = 3; and BNI Grade IIIb, n = 1). No adverse effects of radiation were observed after a single SRS. Two patients developed hyperesthesia in the palatoglossal arch 5 and 8 months after repeat SRS, respectively. CONCLUSIONS Stereotactic radiosurgery for intractable, medically refractory glossopharyngeal neuralgia provided lasting pain reduction in 55% of patients after 1 or 2 SRS procedures. Patients who had a poor response or pain recurrence may require additional procedures such as repeat SRS, MVD, nerve blocks, or nerve section. No patient developed changes in vocal cord function or swallowing disorders after SRS in this study.

Management approach for recurrent brain metastases following upfront radiosurgery may affect risk of subsequent radiation necrosis

PurposeMany patients treated with stereotactic radiosurgery (SRS) alone as initial treatment require 1 or more subsequent salvage therapies. This study aimed to determine if commonly used salvage strategies are associated with differing risks of radiation necrosis (RN). Methods and materialsAll patients treated with upfront SRS alone for brain metastases at our institution were retrospectively analyzed. Salvage treatment details were obtained for brain failures. Patients who underwent repeat SRS to the same lesion were excluded. RN was determined based on pathological confirmation or advanced brain imaging consistent with RN in a symptomatic patient. Patients were grouped according to salvage treatment and rates of RN were compared via Fisher's exact tests. ResultsOf 284 patients treated with upfront SRS alone, 132 received salvage therapy and 44 received multiple salvage treatments. This included 31 repeat SRS alone, 58 whole brain radiation therapy (WBRT) alone, 28 SRS and WBRT, 7 surgery alone, and 8 surgery with adjuvant radiation. With a median follow-up of 10 months, the rate of RN among all patients was 3.17% (9/284), salvaged patients 4.55% (6/132), and never salvaged patients 1.97% (3/152). Receiving salvage therapy did not significantly increase RN risk (P = .31). Of the patients requiring salvage treatments, the highest RN rate was among patients that had both salvage SRS and WBRT (delivered as separate salvage therapies) (6/28, 21.42%). RN rate in this group was significantly higher than in those treated with repeat SRS alone (0/31), WBRT alone (0/58), surgery alone (0/7), and surgery with adjuvant radiation (0/8). Comparing salvage WBRT doses <30 Gy versus ≥30 Gy revealed no effect of dose on RN rate. Additionally, among patients who received multiple SRS treatments, number of treated lesions was not predictive of RN incidence. ConclusionOur results suggest that initial management approach for recurrent brain metastasis after upfront SRS does not affect the rate of RN. However, the risk of RN significantly increases when patients are treated with both repeat SRS and salvage WBRT. Methods to improve prediction of toxicity and optimize patient selection for salvage treatments are needed.

The clinical significance of persistent trigeminal nerve contrast enhancement in patients who undergo repeat radiosurgery.

OBJECTIVE Contrast enhancement of the retrogasserian trigeminal nerve on MRI scans frequently develops after radiosurgical ablation for the management of medically refractory trigeminal neuralgia (TN). The authors sought to evaluate the clinical significance of this imaging finding in patients who underwent a second radiosurgical procedure for recurrent TN. METHODS During a 22-year period, 360 patients underwent Gamma Knife stereotactic radiosurgery (SRS) as their first surgical procedure for TN at the authors' center. The authors retrospectively analyzed the data from 59 patients (mean age 72 years, range 33-89 years) who underwent repeat SRS for recurrent pain at a median of 30 months (range 6-146 months) after the first SRS. The isocenter was 4 mm, and the median maximum doses for the first and second procedures were 80 Gy and 70 Gy, respectively. A neuroradiologist and a neurosurgeon blinded to the treated side evaluated the presence of nerve contrast enhancement on MRI series at the time of the repeat procedure. The authors correlated the presence of this imaging change with clinical outcomes. Pain outcomes and development of trigeminal sensory dysfunction were evaluated with the Barrow Neurological Institute (BNI) Pain Scale and BNI Numbness Scale, respectively. The mean length of follow-up after the second SRS was 58 months (95% CI 49-68 months). RESULTS At the time of the repeat SRS, contrast enhancement of the trigeminal nerve on MRI scans was observed in 31 patients (53%). Five years after the SRS, patients with this enhancement had lower actuarial rates of complete pain relief after the repeat SRS (27% [95% CI 7%-47%]) than patients without the enhancement (76% [95% CI 58%-94%]) (p < 0.001). At the 5-year follow-up, patients with the contrast enhancement also had a higher risk for trigeminal sensory loss after repeat SRS (75% [95% CI 59%-91%]) than patients without contrast enhancement (26% [95% CI 10%-42%]) (p = 0.001). Dysesthetic pain after repeat SRS was observed for 8 patients with and for 2 patients without contrast enhancement. CONCLUSIONS Trigeminal nerve contrast enhancement on MRI scans observed at the time of a repeat SRS for TN was associated with less satisfactory pain control and more frequently detected facial sensory loss. Residual contrast enhancement at the time of a repeat SRS may warrant consideration of dose reduction or further separation of the radiosurgical targets.

Stereotactic radiosurgery for recurrent vestibular schwannoma after previous resection

OBJECTIVE The goal of this retrospective cohort study was to assess long-term outcomes in patients with vestibular schwannoma (VS) who underwent stereotactic radiosurgery (SRS) after initial microsurgical resection. METHODS From the authors' database of 1770 patients with VS, the authors retrospectively analyzed data from 173 Gamma Knife SRS procedures for VS after 1 (128 procedures) or multiple (45 procedures) microsurgical resections. The median length of the interval between the last resection and SRS was 42 months (range 2-329 months). The median length of clinical follow-up was 74 months (range 6-285 months). Progression-free survival after SRS was determined with Kaplan-Meier analysis. RESULTS At the time of SRS, the hearing of 161 patients (93%) was Gardner-Robertson Class V, and 81 patients (47%) had facial neuropathy (i.e., facial function with House-Brackmann [HB] grades of III-VI), 87 (50%) had trigeminal neuropathy, and 71 (41%) reported imbalance or disequilibrium disorders. The median tumor volume was 2.7 cm3 (range 0.2-21.6 cm3), and the median dose to the tumor margin was 13 Gy (range 11-20 Gy). Radiosurgery controlled growth of 163 (94%) tumors. Progression-free survival after SRS was 97% at 3 years, 95% at 5 years, and 90% at 10 years. Four patients with delayed tumor progression underwent repeat SRS at a median of 35 months (range 23-64 months) after the first SRS. Four patients (2.3%) with tumor progression underwent repeat resection at a median of 25 months (range 19-33 months). Among the patients with any facial dysfunction (indicated by HB grades of II-VI), 19% had improvement in this condition after SRS, and 5.5% with some facial function (indicated by HB grades of I-V) developed more facial weakness. Among patients with trigeminal neuropathy, 20% had improvement in this condition, and 5.8% developed or had worsened trigeminal neuropathy after SRS. CONCLUSIONS Stereotactic radiosurgery offered a safe and effective long-term management strategy for VS patients whose tumors remained or recurred after initial microsurgery.

Management Approach for Recurrent Brain Metastases Following Upfront Radiosurgery May Affect Risk of Subsequent Radiation Necrosis

Purpose Many patients treated with stereotactic radiosurgery (SRS) alone as initial treatment require 1 or more subsequent salvage therapies. This study aimed to determine if commonly used salvage strategies are associated with differing risks of radiation necrosis (RN). Methods and materials All patients treated with upfront SRS alone for brain metastases at our institution were retrospectively analyzed. Salvage treatment details were obtained for brain failures. Patients who underwent repeat SRS to the same lesion were excluded. RN was determined based on pathological confirmation or advanced brain imaging consistent with RN in a symptomatic patient. Patients were grouped according to salvage treatment and rates of RN were compared via Fisher's exact tests. Results Of 284 patients treated with upfront SRS alone, 132 received salvage therapy and 44 received multiple salvage treatments. This included 31 repeat SRS alone, 58 whole brain radiation therapy (WBRT) alone, 28 SRS and WBRT, 7 surgery alone, and 8 surgery with adjuvant radiation. With a median follow-up of 10 months, the rate of RN among all patients was 3.17% (9/284), salvaged patients 4.55% (6/132), and never salvaged patients 1.97% (3/152). Receiving salvage therapy did not significantly increase RN risk (P = .31). Of the patients requiring salvage treatments, the highest RN rate was among patients that had both salvage SRS and WBRT (delivered as separate salvage therapies) (6/28, 21.42%). RN rate in this group was significantly higher than in those treated with repeat SRS alone (0/31), WBRT alone (0/58), surgery alone (0/7), and surgery with adjuvant radiation (0/8). Comparing salvage WBRT doses <30 Gy versus ≥30 Gy revealed no effect of dose on RN rate. Additionally, among patients who received multiple SRS treatments, number of treated lesions was not predictive of RN incidence. Conclusion Our results suggest that initial management approach for recurrent brain metastasis after upfront SRS does not affect the rate of RN. However, the risk of RN significantly increases when patients are treated with both repeat SRS and salvage WBRT. Methods to improve prediction of toxicity and optimize patient selection for salvage treatments are needed.

Gamma knife radiosurgery for the management of cerebral metastases from non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is the most frequent cancer that metastasizes to brain. Stereotactic radiosurgery (SRS) has become the management of choice for most patients with such metastatic tumors. Therefore, the authors endeavored to elucidate the survival and SRS outcomes for patients with NSCLC metastasis at their center. In this single-institution retrospective analysis, the authors reviewed their experience with NSCLC metastasis during a 10-year period from 2001 to 2010. Seven hundred twenty patients underwent Gamma Knife radiosurgery. A total of 1004 SRS procedures were performed, and 3143 tumors were treated. The NSCLC subtype was adenocarcinoma in 386 patients, squamous cell carcinoma in 111 patients, and large cell carcinoma in 34 patients. The median aggregate tumor volume was 4.5 cm(3) (range 0.1-88 cm(3)). The median survival time after diagnosis of brain metastasis from NSCLC was 12.6 months, and the median survival after SRS was 8.5 months. The 1-, 2-, and 5-year survival rates after SRS were 39%, 21%, and 10%, respectively. Postradiosurgery survival was decreased in patients treated with prior whole-brain radiation therapy compared with SRS alone (p = 0.003). Aggregate tumor volume was inversely related to survival after SRS (p < 0.001), and the histological subgroups demonstrated significant survival differences (p = 0.023). The overall local tumor control rate in the entire group was 92.8%. One hundred seventy-four patients (24%) underwent repeat SRS for new or resistant metastatic deposits. Stereotactic radiosurgery is an effective means of providing local control for NSCLC metastases. Neurological function and survival benefit from serial patient monitoring and repeat SRS for new tumors.

Stereotactic radiosurgery for arteriovenous malformations of the postgeniculate visual pathway.

A visual field deficit resulting from the management of an arteriovenous malformation (AVM) significantly impacts a patient's quality of life. The present study was designed to investigate the clinical and radiological outcomes of stereotactic radiosurgery (SRS) performed for AVMs involving the postgeniculate visual pathway. In this retrospective single-institution analysis, the authors reviewed their experience with Gamma Knife surgery for postgeniculate visual pathway AVMs performed during the period between 1987 and 2009. During the study interval, 171 patients underwent SRS for AVMs in this region. Forty-one patients (24%) had a visual deficit prior to SRS. The median target volume was 6.0 cm3 (range 0.4-22 cm3), and 19 Gy (range 14-25 Gy) was the median margin dose. Obliteration of the AVM was confirmed in 80 patients after a single SRS procedure at a median follow-up of 74 months (range 5-297 months). The actuarial rate of total obliteration was 67% at 4 years. Arteriovenous malformations with a volume<5 cm3 had obliteration rates of 60% at 3 years and 79% at 4 years. The delivered margin dose proved significant given that 82% of patients receiving ≥22 Gy had complete obliteration. The AVM was completely obliterated in an additional 18 patients after they underwent repeat SRS. At a median of 25 months (range 11-107 months) after SRS, 9 patients developed new or worsened visual field deficits. One patient developed a complete homonymous hemianopia, and 8 patients developed quadrantanopias. The actuarial risk of sustaining a new visual deficit was 3% at 3 years, 5% at 5 years, and 8% at 10 years. Fifteen patients had hemorrhage during the latency period, resulting in death in 9 of the patients. The annual hemorrhage rate during the latency interval was 2%, and no hemorrhages occurred after confirmed obliteration. Despite an overall treatment mortality of 5%, related to latency interval hemorrhage, SRS was associated with only a 5.6% risk of new visual deficit and a final obliteration rate close to 80% in patients with AVMs of the postgeniculate visual pathway.

Extracranial-Intracranial Bypass and the Versatile Vertebral Artery

We tested the validity of 5 prognostic indices, Recursive Partitioning Analysis (RPA), Score Index for Radiosurgery (SIR), Basic Score for Brain Metastases (BSBM), Graded Prognostic Assessment (GPA), and Modified-RPA, for patients who underwent repeat stereotactic radiosurgery (re-SRS).For this study, we used our database, which included 804 patients who underwent gamma knife re-SRS during the period 1998–2013.There were statistically significant survival differences among patients stratified into 3 or 4 groups based on the 5 systems (P < 0.001). With RPA, SIR, BSBM, and the Modified-RPA, there were statistically significant median survival time (MST) differences between any 2 pairs within the 3/4 groups. With the GPA system, however, the MST difference between the GPA 3.5–4.0 and GPA 3.0 groups did not reach statistical significance (P = 0.48). There were large patient number discrepancies among the 3/4 groups in the RPA, SIR, BSBM, and GPA whereas patient numbers were very similar among the 3 Modified-RPA system groups. Our present results show the RPA and BSBM systems to reflect changes less well, with 86%–95% of patients remaining in the same categories between the first and second SRS procedures. However, with SIR, GPA, and the Modified-RPA, 25%–31% of patients were categorized into different subclasses, either better or worse. With the modified-RPA system, such categorical change correlated well with post-re-SRS MSTs.Among the 5 systems, based on patient number proportions, MST separation among the 3/4 groups, and/or detailed reflection of status changes, the Modified-RPA system was shown to be most applicable to re-SRS patients.