Predicting long-term outcomes after microvascular decompression for hemifacial spasm according to lateral spread response and immediate postoperative outcomes: a cohort study.

OBJECTIVE: Microvascular decompression (MVD) is a well-established and highly effective treatment option for hemifacial spasm (HFS). Lateral spread response (LSR) has been used as an intraoperative indicator of HFS resolution, with controversial reliability. The purpose of this study was to determine long-term outcomes of MVD for HFS and the role of LSR and other preoperative predictors. METHODS: The authors conducted a cohort study of all patients treated with MVD for HFS at a single institution from January 1, 1998, to December 31, 2019. In addition to a retrospective chart review, all patients were contacted at the time of the study to provide informed consent and responded to a telephone survey to ascertain their current disease and medication status. Patients with at least 12 months of postoperative follow-up were included. Statistical testing included a Student t-test, Fisher's exact test, logistic regression, and Cox proportional hazards analysis. RESULTS: One hundred nineteen patients met study criteria; 41 (34%) had at least 10 years of clinical follow-up. HFS fully resolved in 93 (78%), symptoms subjectively improved in 11 (9%) and were unchanged in 15 (13%). Immediate postoperative HFS status did not correlate with long-term outcome (p = 0.13). Changes in LSR were not associated with outcome. Patients receiving neuromodulating agents had significantly longer preoperative duration of symptoms and were more likely to show persistent LSR intraoperatively. HFS recurrence was associated with younger age at the time of surgery but not with intraoperative LSR resolution. CONCLUSIONS: This study demonstrated that MVD for HFS is highly effective for most patients. Neither intraoperative LSR change nor immediate postoperative status was predictive of long-term outcomes.

Treatment outcomes of single-fraction stereotactic radiosurgery for adenoid cystic carcinoma: a case series of 55 patients.

PURPOSE: This study aimed to analyze the treatment outcomes of single-fraction stereotactic radiosurgery (SRS) for adenoid cystic carcinoma patients. METHODS: Retrospective analysis was conducted for 55 patients with 66 lesions. SRS intentions were categorized as definitive, adjuvant, salvage, and palliative. Tumor control was defined as local (within 50% isodose line), marginal (outside 50% isodose line), and distant (metastasis outside head/neck). RESULTS: The median age was 60 years (range 21-85), with 53% males. Tumor origin was head/neck for 88% and trachea/lung for 12%. 61% were recurrent lesions. Median interval from diagnosis to SRS was 14 months. Preceding surgery was performed in 30%. SRS was administered as definitive (30 lesions), adjuvant (13), salvage (19), and palliative (4). SRS was used as a boost to external beam radiation therapy (EBRT) in 39%. Concurrent chemotherapy was administered in 26%. 5-, 10-, and 15-year local control rates were 60%, 33%, and 27%, respectively; local/marginal control rates were 29%, 13%, and 10%. For recurrent lesions treated with SRS without EBRT, 5-year local control rate was 14%, and local/marginal control rate was 5%. For recurrent lesions treated with SRS and EBRT, 5-year local control rate was 100%, and local/marginal control rate was 40%. The rate of distant failure after SRS was 40%. Older age and distant metastasis before SRS were negative factors for overall survival. CONCLUSION: SRS provided a high rate of local tumor control, but marginal failure was frequent. Integrating SRS with added EBRT exhibits potential for enhancing local and local/marginal tumor control, particularly in recurrent cases.

The longitudinal risk of hemorrhage of melanoma brain metastases after Gamma Knife radiosurgery.

OBJECTIVE: The objective of this study was to analyze the hemorrhagic risk of melanoma brain metastases after Gamma Knife radiosurgery (GKRS). METHODS: A prospective institutional database was retrospectively queried to identify patients who underwent GKRS for melanoma brain metastases between 1990 and 2021. Lesional hemorrhage was defined as definite or possible based on radiologists' readings, and severity was graded according to Common Terminology Criteria for Adverse Events. RESULTS: Two hundred ninety-one patients with 1083 lesions treated in 419 sessions were identified. The mean (± SD) patient age was 60 ± 15 years, and 61% were male. The median follow-up period for overall survival (OS) was 11 (range 0-214) months with 581 patient-years. Definite/possible lesional hemorrhages occurred in 13% of lesions, with grade 3 hemorrhages observed in 4% of lesions. Surgical intervention was required in 2% of cases (5% of patients), and all resected lesions were pathologically consistent with melanoma. A decreased risk of definite/possible lesional hemorrhage was associated with a later time period between 2015 and 2021 (OR 0.45, 95% CI 0.266-0.75, p = 0.0021), increased marginal dose (OR 0.91, 95% CI 0.83-0.99, p = 0.037), antiplatelet use post-GKRS (OR 0.195, 95% CI 0.083-0.46, p < 0.001), and whole-brain radiotherapy (WBRT; OR 0.53, 95% CI 0.344-0.82, p = 0.0042). After 2015, more patients received anticoagulation, B-Raf proto-oncogene inhibitors, and immune checkpoint inhibitors, and fewer received bevacizumab (p < 0.001). The cumulative risk of lesional hemorrhage was 17%-20% at 36 months from GKRS, with 95%-96% of cases occurring within 12 months. The median patient OS was 11 (95% CI 9-13) months, and multivariate Cox regression analysis revealed that antiplatelet agents (hazard ratio [HR] 0.66, 95% CI 0.45-0.96, p = 0.031) and immune checkpoint inhibitors (HR 0.35, 95% CI 0.26-0.48, p < 0.001) were associated with longer OS, while WBRT (HR 1.36, 95% CI 1.02-1.81, p = 0.037) and definite/possible hemorrhage (HR 1.39, 95% CI 1.04-1.85, p = 0.024) were associated with shorter OS. CONCLUSIONS: The definite hemorrhage risk of melanoma brain metastases after GKRS was 17% in the first 3 years and 95% of the lesional hemorrhage occurred within the 1st year. Surgical intervention was needed in 5% of patients. Antiplatelet agents and immune checkpoint inhibitors were associated with improved OS, while definite/possible hemorrhage was associated with worse OS.

Management of sporadic intracanalicular vestibular schwannomas: A critical review and International Stereotactic Radiosurgery Society (ISRS) practice guidelines.

BACKGROUND: The choice of an appropriate strategy for intracanalicular vestibular schwannoma (ICVS) is still debated. We conducted a systematic review and meta-analysis with the aim to compare treatment outcomes amongst management strategies (conservative surveillance (CS), microsurgical resection (MR), or stereotactic radiosurgery (SRS)) aiming to inform guideline recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS). METHODS: Using PRISMA guidelines, we reviewed manuscripts published between January 1990 and October 2021 referenced in PubMed or Embase. Inclusion criteria were peer-reviewed clinical studies or case series reporting a cohort of ICVS managed with CS, MR, or SRS. Primary outcome measures included tumor control, the need for additional treatment, hearing outcomes, and posttreatment neurological deficits. These were pooled using meta-analytical techniques and compared using meta-regression with random effect. RESULTS: Forty studies were included (2371 patients). The weighted pooled estimates for tumor control were 96% and 65% in SRS and CS series, respectively (P < .001). Need for further treatment was reported in 1%, 2%, and 25% for SRS, MR, and CS, respectively (P = .001). Hearing preservation was reported in 67%, 68%, and 55% for SRS, MR, and CS, respectively (P = .21). Persistent facial nerve deficit was reported in 0.1% and 10% for SRS and MR series, respectively (P = .01). CONCLUSIONS: SRS is a noninvasive treatment with at least equivalent rates of tumor control and hearing preservation as compared to MR, with the caveat of better facial nerve preservation. As compared to CS, upfront SRS is an effective treatment in achieving tumor control with similar rates of hearing preservation.

Single-fraction radiosurgery outcomes for large vestibular schwannomas in the upfront or post-surgical setting: a systematic review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines.

PURPOSE: To perform a systematic review of literature specific to single-fraction stereotactic radiosurgery (SRS) for large vestibular schwannomas (VS), maximum diameter ≥ 2.5 cm and/or classified as Koos Grade IV, and to present consensus recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS). METHODS: The Medline and Embase databases were used to apply the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. We considered eligible prospective and retrospective studies, written in the English language, reporting treatment outcomes for large VS; SRS for large post-operative tumors were analyzed in aggregate and separately. RESULTS: 19 of the 229 studies initially identified met the final inclusion criteria. Overall crude rate of tumor control was 89% (93.7% with no prior surgery vs 87.7% with prior surgery). Rates of salvage microsurgical resection, need for shunt, and additional SRS in all series versus those with no prior surgery were 9.6% vs 3.3%, 4.7% vs 6.4% and 1% vs 0.9%, respectively. Rates of facial palsy and hearing preservation in all series versus those with no prior surgery were 1.3% vs 3.4% and 34.2% vs 40.4%, respectively. CONCLUSIONS: Upfront SRS resulted in high rates of tumor control with acceptable rates of facial palsy and hearing preservation as compared to the results in those series including patients with prior surgery (level C evidence). Therefore, although large VS are considered classic indication for microsurgical resection, upfront SRS can be considered in selected patients and we recommend a prescribed marginal dose from 11 to 13 Gy (level C evidence).

ISRS Technical Guidelines for Stereotactic Radiosurgery: Treatment of Small Brain Metastases (≤1 cm in Diameter).

PURPOSE: The objective of this literature review was to develop International Stereotactic Radiosurgery Society (ISRS) consensus technical guidelines for the treatment of small, ≤1 cm in maximal diameter, intracranial metastases with stereotactic radiosurgery. Although different stereotactic radiosurgery technologies are available, most of them have similar treatment workflows and common technical challenges that are described. METHODS AND MATERIALS: A systematic review of the literature published between 2009 and 2020 was performed in Pubmed using the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) methodology. The search terms were limited to those related to radiosurgery of brain metastases and to publications in the English language. RESULTS: From 484 collected abstract 37 articles were included into the detailed review and bibliographic analysis. An additional 44 papers were identified as relevant from a search of the references. The 81 papers, including additional 7 international guidelines, were deemed relevant to at least one of five areas that were considered paramount for this report. These areas of technical focus have been employed to structure these guidelines: imaging specifications, target volume delineation and localization practices, use of margins, treatment planning techniques, and patient positioning. CONCLUSIONS: This systematic review has demonstrated that Stereotactic Radiosurgery (SRS) for small (1 cm) brain metastases can be safely performed on both Gamma Knife (GK) and CyberKnife (CK) as well as on modern LINACs, specifically tailored for radiosurgical procedures, However, considerable expertise and resources are required for a program based on the latest evidence for best practice.

Salvage radiosurgery following subtotal resection of vestibular schwannomas: does timing influence tumor control?

OBJECTIVE: The goal of microsurgical resection of vestibular schwannoma (VS) is gross-total resection (GTR) to provide oncological cure. However, a popular strategy is to halt the resection if the surgical team feels the risk of cranial nerve injury is imminent, achieving a maximally safe subtotal resection (STR) instead. The tumor remnant can then be treated with stereotactic radiosurgery (SRS) once the patient has recovered from the immediate postoperative period, or it can be followed with serial imaging and treated with SRS in a delayed fashion if residual tumor growth is seen. In this study, the authors evaluated the efficacy of this multimodality approach, particularly the influence of timing and dose of SRS on radiological tumor control, need for salvage treatment, and cranial nerve function. METHODS: VS patients treated with initial microsurgery and subsequent radiosurgery were retrospectively included from two tertiary treatment centers and dichotomized depending on whether SRS was given upfront (defined as before 12 months) or later. Radiological tumor control was defined as less than 20% tumor volume expansion and oncological tumor control as an absence of salvage treatment. Facial and cochlear nerve functions were assessed after surgery, at the time of SRS, and at last follow-up. Finally, a systematic literature review was conducted according to PRISMA guidelines. RESULTS: A total of 110 VS patients underwent SRS following microsurgical resection, with a mean preradiosurgical tumor volume of 2.2 cm3 (SD 2.5 cm3) and mean post-SRS follow-up time of 5.8 years (SD 4.1 years). The overall radiological tumor control and oncological tumor control were 77.3% and 90.9%, respectively. Thirty-five patients (31.8%) received upfront SRS, while 75 patients (68.2%) were observed for a minimum of 12 months prior to SRS. The timing of SRS did not influence the radiological tumor control (p = 0.869), the oncological tumor control (p = 0.560), or facial nerve (p = 0.413) or cochlear nerve (p = 0.954) function. An escalated marginal dose (> 12 Gy) was associated with greater tumor shrinkage (p = 0.020) and superior radiological tumor control (p = 0.020), but it did not influence the risk of salvage treatment (p = 0.904) or facial (p = 0.351) or cochlear (p = 0.601) nerve deterioration. CONCLUSIONS: Delayed SRS after close observation of residuals following STR is a safe alternative to upfront SRS regarding tumor control and cranial nerve preservation in selected patients.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Pituitary Adenoma Incidence, Management Trends, and Long-term Outcomes: A 30-Year Population-Based Analysis.

OBJECTIVE: To perform a population-based study of pituitary adenoma epidemiology, including longitudinal trends in disease incidence, treatment patterns, and outcomes. PATIENTS AND METHODS: In this study of incident pituitary adenomas in Olmsted County, Minnesota, from January 1, 1989, through December 31, 2019, we identified 785 patients who underwent primary screening, 435 of whom were confirmed as harboring incident pituitary adenomas and were included. Primary outcomes of interest included demographic characteristics, presenting features, and disease outcomes (tumor control, biochemical control, and complications). RESULTS: Among our 435 study patients, 438 unique pituitary adenomas were diagnosed at a median patient age of 39 years (interquartile range [IQR], 27 to 58 years). Adenomas were incidentally identified in 164 of the 438 tumors (37%). Common symptomatic presentations included hyperprolactinemia (188 of 438 [43%]) and visual field deficit (47 of 438 [11%]). Laboratory tests confirmed pituitary hormone hypersecretion in 238 of the 435 patients (55%), which was symptomatic in 222. The median tumor diameter was 8 mm (IQR, 5 to 17 mm). Primary management strategies were observation (156 of 438 tumors [36%]), medication (162 of 438 tumors [37%]), and transsphenoidal resection (120 of 438 tumors [27%]). Tumor and biochemical control were achieved in 398 (95%) and 216 (91%) secreting tumors, respectively. New posttreatment pituitary or visual deficits were noted in 43 (11%) and 8 (2%); apoplexy occurred in 28 (6%). Median clinical follow-up was 98 months (IQR, 47 to 189 months). Standardized incidence rates were 3.77 to 16.87 per 100,000 population, demonstrating linear expansion over time (R2=0.67). The mean overall standardized incidence rate was 10.1 per 100,000 population; final point prevalence was 175.1 per 100,000 population. CONCLUSION: Pituitary adenoma is a highly incident disease, with prolactin-secreting and incidental lesions representing the majority of tumors. Incidence rates and asymptomatic detection appear to be increasing over time. Presenting symptoms and treatment pathways are variable; however, most patients achieve favorable outcomes with observation or a single treatment modality.

Delayed recurrence of pediatric arteriovenous malformations after radiologically confirmed obliteration.

OBJECTIVE: Arteriovenous malformations (AVMs) are a major cause of intracerebral hemorrhage in children, resulting in significant morbidity and mortality. Moreover, the rate of AVM recurrence in children is significantly higher than in adults. The aim of this study was to define the risk of delayed pediatric AVM (pAVM) recurrence following confirmed radiological obliteration. Further understanding of this risk could inform the role of long-term radiological surveillance. METHODS: The authors conducted a retrospective review of ruptured and unruptured pAVM cases treated at a single tertiary care referral center between 1994 and 2019. Demographics, clinical characteristics, treatment modalities, and AVM recurrence were analyzed. RESULTS: A total of 102 pediatric patients with intracranial AVMs, including 52 (51%) ruptured cases, were identified. The mean patient age at presentation was 11.2 ± 4.4 years, and 51 (50%) patients were female. The mean nidus size was 2.66 ± 1.44 cm. The most common Spetzler-Martin grades were III (32%) and II (31%). Stereotactic radiosurgery was performed in 69.6% of patients. AVM obliteration was radiologically confirmed in 68 (72.3%) of 94 patients with follow-up imaging, on angiography in 50 (73.5%) patients and on magnetic resonance imaging in 18 (26.5%). AVM recurrence was identified in 1 (2.3%) of 43 patients with long-term surveillance imaging over a mean follow-up of 54.7 ± 38.9 months (range 2-153 months). This recurrence was identified in a boy who had presented with a ruptured AVM and had been surgically treated at 5 years of age. The AVM recurred 54 months after confirmed obliteration on surveillance digital subtraction angiography. Two other cases of presumed AVM recurrence following resection in young children were excluded from recurrence analysis because of incomplete sets of imaging available for review. CONCLUSIONS: AVM recurrence following confirmed obliteration on imaging is a rare phenomenon, though it occurs more frequently in the pediatric population. Regular long-term follow-up with dedicated surveillance angiography is recommended even after obliteration following resection.

The Effect of Prescription Isodose Variation on Tumor Control and Toxicities in Stereotactic Radiosurgery for Sporadic Vestibular Schwannoma: Propensity Score-Matched Case-Control Study.

Objective Vestibular schwannoma (VS) treated with Gamma Knife stereotactic radiosurgery (SRS) was typically performed at 50% isodose line (IDL50); however, the impact of IDL variation on outcomes is poorly understood. This study aimed to compare tumor control (TC) and toxicities between treatment at 40% (IDL40) and 50% (IDL50). Methods Sporadic/unilateral VS patients treated with SRS dose 12 to 14 Gy and prescription isodose volume ≤10cm 3 were included. Propensity score matching was applied to IDL40 cohort to generate an IDL50 companion cohort, adjusting for age and prescription isodose volume. After exclusion of patients with follow-up <24 months, there were 30 and 28 patients in IDL40 and IDL50 cohorts, respectively. Results Median follow-up time was 96 months (24-225 months). Actuarial and radiographic TC rates were 91.8% and clinical TC was 96.2% both at 5 and 10 years. TC was higher in IDL40 cohort but not significant (96.4 vs. 86.7%; p = 0.243). Hearing preservation (HP) rates were 71.9 and 39.2% at 5- and 10-year intervals, with significantly higher rates of HP noted in IDL40 cohort (83.3 vs. 57.1% at 5-year interval; 62.5 vs. 11.4% at 10-year interval; p = 0.017). Permanent facial neuropathy occurred in two patients, both from the IDL50 cohort (3.5%). Rates of post-SRS steroid treatment or shunt placement for hydrocephalus were slightly higher in IDL50 patients (6.9 vs. 17.9%; p = 0.208 and 3.3 vs. 7.1%; p = 0.532). Conclusion For treatment of VS with SRS, dose prescription at IDL40 or IDL50 provides excellent long-term TC and toxicity profiles. IDL40 may be associated with improved long-term HP.

Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Systematic Review and Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines.

BACKGROUND: Dural arteriovenous fistulas (dAVFs) are often treated with stereotactic radiosurgery (SRS) to achieve complete obliteration (CO), prevent future hemorrhages, and ameliorate neurological symptoms. OBJECTIVE: To summarize outcomes after SRS for dAVFs and propose relevant practice recommendations. METHODS: Using a PICOS/PRISMA/MOOSE protocol, we included patients with dAVFs treated with SRS and data for at least one of the outcomes of the study. Relevant outcomes were CO, symptom improvement and cure, and post-SRS hemorrhage or permanent neurological deficits (PNDs). Estimated outcome effect sizes were determined using weighted random-effects meta-analyses using DerSimonian and Laird methods. To assess potential relationships between patient and lesion characteristics and clinical outcomes, mixed-effects weighted regression models were used. RESULTS: Across 21 published studies, we identified 705 patients with 721 dAVFs treated with SRS. The CO rate was 68.6% (95% CI 60.7%-76.5%) with symptom improvement and cure rates of 97.2% (95% CI 93.2%-100%) and 78.8% (95% CI 69.3%-88.2%), respectively. Estimated incidences of post-SRS hemorrhage and PNDs were 1.1% (95% CI 0.6%-1.6%) and 1.3% (95% CI 0.8%-1.8%), respectively. Noncavernous sinus (NCS) dAVFs were associated with lower CO (P = .03) and symptom cure rates (P = .001). Higher grade was also associated with lower symptom cure rates (P = .04), whereas previous embolization was associated with higher symptom cure rates (P = .01). CONCLUSION: SRS for dAVFs results in CO in the majority of patients with excellent symptom improvement rates with minimal toxicity. Patients with NCS and/or higher-grade dAVFs have poorer symptom cure rates. Combined therapy with embolization and SRS is recommended when feasible for clinically aggressive dAVFs or those refractory to embolization to maximize the likelihood of symptom cure.

Stereotactic Radiosurgery for Postoperative Spine Malignancy: A Systematic Review and International Stereotactic Radiosurgery Society Practice Guidelines.

PURPOSE: To determine safety and efficacy of postoperative spine stereotactic body radiation therapy (SBRT) in the published literature, and to present practice recommendations on behalf of the International Stereotactic Radiosurgery Society. METHODS AND MATERIALS: A systematic review of the literature was performed, specific to postoperative spine SBRT, using PubMed and Embase databases. A meta-analysis for 1-year local control (LC), overall survival (OS), and vertebral compression fracture probability was conducted. RESULTS: The literature search revealed 251 potentially relevant articles after duplicates were removed. Of these 56 were reviewed in-depth for eligibility and 12 met all the inclusion criteria for analysis. 7 studies were retrospective, 2 prospective observational and 3 were prospective phase 1 and 2 clinical trials. Outcomes for a total of 461 patients and 499 spinal segments were reported. Ten studies used a magnetic resonance imaging (MRI) scan fused to computed tomography (CT) simulation for treatment planning, and 2 investigations reported on all patients receiving a CT-myelogram at the time of planning. Meta-analysis for 1 year LC and OS was 88.9% and 57%, respectively. The crude reported vertebral compression fracture rate was 5.6%. One case of myelopathy was described in a patient with a previously irradiated spinal segment. One patient developed an esophageal fistula requiring surgical repair. CONCLUSIONS: Postoperative spine SBRT delivers a high 1-year LC with acceptably low toxicity. Patients who may benefit from this include those with oligometastatic disease, radioresistant histology, paraspinal masses, or those with a history of prior irradiation to the affected spinal segment. The International Stereotactic Radiosurgery Society recommends a minimum interval of 8 to 14 days after invasive surgery before simulation for SBRT, with initiation of radiation therapy within 4 weeks of surgery. An MRI fused to the planning CT, or the use of a CT-myelogram, are necessary for target and organ-at-risk delineation. A planning organ-at-risk volume (PRV) of 1.5 to 2 mm for the spinal cord is advised.

Stereotactic radiosurgery for secretory pituitary adenomas: systematic review and International Stereotactic Radiosurgery Society practice recommendations.

OBJECTIVE: A systematic review was performed to provide objective evidence on the use of stereotactic radiosurgery (SRS) in the management of secretory pituitary adenomas and develop consensus recommendations. METHODS: The authors performed a systematic review of the English-language literature up until June 2018 using the PRISMA guidelines. The PubMed (Medline), Embase, and Cochrane databases were searched. A total of 45 articles reporting single-institution outcomes of SRS for acromegaly, Cushing's disease, and prolactinomas were selected and included in the analysis. RESULTS: For acromegaly, random effects meta-analysis estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rates were 97.0% (95% CI 96.0%-98.0%), 44.0% (95% CI 35.0%-53.0%), and 17.0% (95% CI 13.0%-23.0%), respectively. For Cushing's disease, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 92.0% (95% CI 87.0%-95.0%), 48.0% (95% CI 35.0%-61.0%), and 21.0% (95% CI 13.0%-31.0%), respectively. For prolactinomas, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 93.0% (95% CI 90.0%-95.0%), 28.0% (95% CI 19.0%-39.0%), and 12.0% (95% CI 6.0%-24.0%), respectively. Meta-regression analysis did not show a statistically significant association between mean margin dose with crude endocrine remission rate or mean margin dose with development of any new hypopituitarism rate for any of the secretory subtypes. CONCLUSIONS: SRS offers effective tumor control of hormone-producing pituitary adenomas in the majority of patients but a lower rate of endocrine improvement or remission.

The role of single-fraction stereotactic radiosurgery for atypical meningiomas (WHO grade II): treatment results based on a 25-year experience.

PURPOSE: To clarify the role of stereotactic radiosurgery (SRS) for atypical meningiomas (AM). METHODS: A retrospective analysis of 68 patients with AM having SRS from 1995 until 2019. RESULTS: Nineteen patients (28%) had undergone prior external beam radiation therapy (EBRT) (median dose, 54 Gy). The median follow-up period was 52 months. Eighteen (26%), 17 (25%), and 33 (49%) patients received SRS as an upfront adjuvant (≤ 6 months), early salvage (7-18 months), or late salvage treatment (> 18 months), respectively. The 3-, 5-, and 10-year progression-free survivals (PFSs) were 52%, 35%, and 25%, respectively. The 3-, 5-, and 10-year disease-specific survivals were 85%, 78%, and 61%, respectively. Adverse radiation events (AREs) were observed in 12 patients (18%), with increased or new seizures being the most frequent complication (n = 7). Prior EBRT was associated with reduced PFS (HR 5.92, P < 0.01), reduced DSS (HR 5.84, P < 0.01), and an increased risk of ARE (HR 3.31, P = 0.04). Timing of SRS was correlated with reduced PFS for patients having early salvage treatment compared to upfront adjuvant (HR 3.17, P = 0.01) or late salvage treatment (HR 4.39, P < 0.01). CONCLUSION: PFS for patients with residual/recurrent AM remains poor despite SRS. Prior EBRT was associated with worse tumor control, higher tumor-related mortality, and an increased risk of ARE. Further study on the timing of SRS is needed to determine if upfront adjunctive SRS improves tumor control compared to salvage SRS.

The Role of Biological Effective Dose in Predicting Obliteration After Stereotactic Radiosurgery of Cerebral Arteriovenous Malformations.

OBJECTIVE: To determine whether biological effective dose (BED) was predictive of obliteration after stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs). PATIENTS AND METHODS: We studied patients undergoing single-session AVM SRS between January 1, 1990, and December 31, 2014, with at least 2 years of imaging follow-up. Excluded were patients with syndromic AVM, previous SRS or embolization, and patients treated with volume-staged SRS. Biological effective dose was calculated using a mono-exponential model described by Jones and Hopewell. The primary outcome was likelihood of total obliteration defined by digital subtraction angiography or magnetic resonance imaging (MRI). Variables were analyzed as continuous and dichotomous variables based on the maximum value of (sensitivity-[1-specificity]). RESULTS: This study included 352 patients (360 AVM, median follow-up, 5.9 years). The median margin dose prescribed was 18.75 Gy (interquartile range [IQR]: 18 to 20 Gy). Two hundred fifty-nine patients (71.9%) had obliteration shown by angiography (n=176) or MRI (n=83) at a median of 36 months after SRS (IQR: 26 to 44 months). Higher BED was associated with increased likelihood of obliteration in univariate Cox regression analyses, when treated as either a dichotomous (≥133 Gy; hazard ratio [HR],1.52; 95% confidence interval [CI], 1.19 to 1.95; P<.001) or continuous variable (HR, 1.00, 95% CI, 1.0002 to 1.005; P=.04). In multivariable analyses including dichotomized BED and location, BED remained associated with obliteration (P=.001). CONCLUSION: Biological effective dose ≥133 Gy was predictive of AVM obliteration after single-session SRS within the prescribed margin dose range 15 to 25 Gy. Further study is warranted to determine whether BED optimization should be considered as well as treatment dose for AVM SRS planning.

Salvage Radiosurgery for Recurrent Supratentorial Primitive Neuroectodermal Tumors: A Single Institutional Series and Review of the Literature.

INTRODUCTION: Supratentorial primitive neuroectodermal tumor is a rare, aggressive intrinsic brain tumor with limited treatment options for recurrent disease. SRS as a treatment modality in the recurrent setting was investigated. METHODS: A retrospective review of 8 patients treated with SRS for local or distant recurrence of supratentorial PNET from 1999 to 2014 was conducted. RESULTS: Thirty-six tumors were treated in 15 sessions in 8 patients. The median patient age was 22.5 (interquartile range [IQR], 14.75-43.5 years) with a median 21-month period from diagnosis until SRS (IQR, 16-23.75 months). The median prescription isodose volume was 1.85 cm3 (IQR, 1.85-7.02 cm3); median tumor margin dose was 18 Gy (IQR 14-20 Gy); and median isocenters was 2 (range 1-13). No patients experienced adverse radiation effects. All but 1 patient died, and the median overall survival was 32 months (IQR, 26.75-53.5 months) with median overall survival following SRS of 9.5 months (IQR, 5.25-30 months). Univariate analysis failed to demonstrate a statistically significant association between age, number of gamma knife treatments, interval to gamma knife, and margin radiation dose with overall survival. DISCUSSION/CONCLUSION: This series supports the use of SRS in patients with recurrent supratentorial PNET following multimodal therapy.

Outcome comparison of patients who develop leptomeningeal disease or distant brain recurrence after brain metastases resection cavity radiosurgery.

BACKGROUND: To compare the outcomes between patients with leptomeningeal disease (LMD) and distant brain recurrence (DBR) after stereotactic radiosurgery (SRS) brain metastases (BM) resection cavity. METHODS: Twenty-nine patients having single-fraction SRS after BM resection who developed either LMD (n = 11) or DBR (n = 18) as their initial and only site of intracranial progression were retrospectively reviewed. RESULTS: Patients developing LMD more commonly had a metachronous presentation (91% vs 50%, P = .04) and recursive partitioning class 1 status (45% vs 6%, P = .02). There was no difference in the median time from SRS to the development of LMD or DBR (5.0 vs 3.8 months, P = .68). The majority of patients with LMD (10/11, 91%) developed the nodular variant (nLMD). Treatment for LMD was repeat SRS (n = 4), whole-brain radiation therapy (WBRT; n = 5), resection + WBRT (n = 1), and no treatment (n = 1). Treatment for DBR was repeat SRS (n = 9), WBRT (n = 3), resection + resection cavity SRS (n = 1), and no treatment (n = 5). Median overall survival (OS) from time of resection cavity SRS was 15.7 months in the LMD group and 12.7 months in the DBR group (P = .60), respectively. Median OS in salvage SRS and salvage WBRT were 25.4 and 5.0 months in the nLMD group (P = .004) while 18.7 and 16.2 months in the DBR group (P = .30), respectively. CONCLUSIONS: Following BM resection cavity SRS, nLMD recurrence is much more frequent than classical LMD. Salvage SRS may be considered for selected patients with nLMD, reserving salvage WBRT for patients with extensive intracranial disease without compromising survival. Further study with larger numbers of patients is needed.

Long-term outcomes of grade I/II skull base chondrosarcoma: an insight into the role of surgery and upfront radiotherapy.

PURPOSE: To clarify the need for post-operative radiation treatment in skull base chondrosarcomas (SBCs). METHODS: A retrospective analysis of patients with grade I or II SBC. Patients were divided according to post-surgical treatment strategies: (A) planned upfront radiotherapy and (B) watchful waiting. Tumor control and survival were compared between the treatment groups. The median follow-up after resection was 105 months (range, 9-376). RESULTS: Thirty-two patients (Grade 1, n = 16; Grade 2, n = 16) were included. The most frequent location was petroclival (21, 64%). A gross total resection (GTR) was achieved in 11 patients (34%). Fourteen (44%) underwent upfront radiotherapy (group A) whereas 18 (56%) were followed with serial MRI alone (group B). The tumor control rate for the entire group was 77% and 69% at 10- and 15-year, respectively. Upfront radiotherapy (P = 0.25), extent of resection (P = 0.11) or tumor grade (P = 0.83) did not affect tumor control. The majority of Group B patients with recurrent tumors (5/7) obtained tumor control with repeat resection (n = 2), salvage radiotherapy (n = 2), or a combination of both (n = 1). The 10-year disease-specific survival was 95% with no difference between the group A and B (P = 0.50). CONCLUSION: For patients with grade I/II SBC, a reasonable strategy is deferral of radiotherapy after maximum safe resection until tumor progression or recurrence. At that time, most patients can be successfully managed with salvage radiotherapy or surgery. Late recurrences may occur, and life-long follow-up is advisable.