Lunsford, L. Dade

BACKGROUNDPatients with renal cell carcinoma (RCC) brain metastases are frequently treated with immune checkpoint inhibitors (ICIs) and stereotactic radiosurgery (SRS). However, data reporting on the risk of developing radiation necrosis (RN) are limited.METHODSRN rates were compared for concurrent therapy (ICI/SRS administration within 4 weeks of one another) and nonconcurrent therapy with the χ2 test. Univariable logistic regression was used to identify factors associated with developing RN.RESULTSFifty patients (23 concurrent and 27 nonconcurrent) with 395 brain metastases were analyzed. The median follow‐up was 12.1 months; the median age was 65 years. The median margin dose was 20 Gy, and 4% underwent prior whole‐brain radiation therapy (WBRT). The median treated tumor volume was 3.32 cm3 (range, 0.06‐42.38 cm3); the median volume of normal brain tissue receiving a dose of 12 Gy or higher (V12 Gy) was 8.42 cm3 (range, 0.27‐111.22 cm3). Any‐grade RN occurred in 17.4% and 22.2% in the concurrent and nonconcurrent groups, respectively (P = .67). Symptomatic RN occurred in 4.3% and 14.8% in the concurrent and nonconcurrent groups, respectively (P = .23). Increased tumor volume during SRS (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.01‐1.19; P = .04) was associated with developing RN, although V12 Gy (OR, 1.03; 95% CI, 0.99‐1.06; P = .06), concurrent therapy (OR, 0.74; 95% CI, 0.17‐2.30; P = .76), prior WBRT, and ICI agents were not statistically significant.CONCLUSIONSSymptomatic RN occurs in a minority of patients with RCC brain metastases treated with ICI/SRS. The majority of events were grade 1 to 3 and were managed medically. Concurrent ICI/SRS does not appear to increase this risk. Attempts to improve dose conformality (reduce V12) may be the most successful mitigation strategy in single‐fraction SRS.

OBJECTIVE There is a reported elevated risk of cerebral aneurysms in patients with intracranial dural arteriovenous fistulas (dAVFs). However, the natural history, rate of spontaneous regression, and ideal treatment regimen are not well characterized. In this study, the authors aimed to describe the characteristics of patients with dAVFs and intracranial aneurysms and propose a classification system. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database from 12 centers was retrospectively reviewed. Analysis was performed to compare dAVF patients with (dAVF+ cohort) and without (dAVF-only cohort) concomitant aneurysm. Aneurysms were categorized based on location as a dAVF flow-related aneurysm (FRA) or a dAVF non–flow-related aneurysm (NFRA), with further classification as extra- or intradural. Patients with traumatic pseudoaneurysms or aneurysms with associated arteriovenous malformations were excluded from the analysis. Patient demographics, dAVF anatomical information, aneurysm information, and follow-up data were collected. RESULTS Of the 1077 patients, 1043 were eligible for inclusion, comprising 978 (93.8%) and 65 (6.2%) in the dAVF-only and dAVF+ cohorts, respectively. There were 96 aneurysms in the dAVF+ cohort; 10 patients (1%) harbored 12 FRAs, and 55 patients (5.3%) harbored 84 NFRAs. Dural AVF+ patients had higher rates of smoking (59.3% vs 35.2%, p < 0.001) and illicit drug use (5.8% vs 1.5%, p = 0.02). Sixteen dAVF+ patients (24.6%) presented with aneurysm rupture, which represented 16.7% of the total aneurysms. One patient (1.5%) had aneurysm rupture during follow-up. Patients with dAVF+ were more likely to have a dAVF located in nonconventional locations, less likely to have arterial supply to the dAVF from external carotid artery branches, and more likely to have supply from pial branches. Rates of cortical venous drainage and Borden type distributions were comparable between cohorts. A minority (12.5%) of aneurysms were FRAs. The majority of the aneurysms underwent treatment via either endovascular (36.5%) or microsurgical (15.6%) technique. A small proportion of aneurysms managed conservatively either with or without dAVF treatment spontaneously regressed (6.2%). CONCLUSIONS Patients with dAVF have a similar risk of harboring a concomitant intracranial aneurysm unrelated to the dAVF (5.3%) compared with the general population (approximately 2%–5%) and a rare risk (0.9%) of harboring an FRA. Only 50% of FRAs are intradural. Dural AVF+ patients have differences in dAVF angioarchitecture. A subset of dAVF+ patients harbor FRAs that may regress after dAVF treatment.

Abstract BACKGROUND Low-grade intracranial dural arteriovenous fistulas (dAVF) have a benign natural history in the majority of cases. The benefit from treatment of these lesions is controversial. OBJECTIVE To compare the outcomes of observation versus intervention for low-grade dAVFs. METHODS We retrospectively reviewed dAVF patients from institutions participating in the CONsortium for Dural arteriovenous fistula Outcomes Research (CONDOR). Patients with low-grade (Borden type I) dAVFs were included and categorized into intervention or observation cohorts. The intervention and observation cohorts were matched in a 1:1 ratio using propensity scores. Primary outcome was modified Rankin Scale (mRS) at final follow-up. Secondary outcomes were excellent (mRS 0-1) and good (mRS 0-2) outcomes, symptomatic improvement, mortality, and obliteration at final follow-up. RESULTS The intervention and observation cohorts comprised 230 and 125 patients, respectively. We found no differences in primary or secondary outcomes between the 2 unmatched cohorts at last follow-up (mean duration 36 mo), except obliteration rate was higher in the intervention cohort (78.5% vs 24.1%, P < .001). The matched intervention and observation cohorts each comprised 78 patients. We also found no differences in primary or secondary outcomes between the matched cohorts except obliteration was also more likely in the matched intervention cohort ( P < .001). Procedural complication rates in the unmatched and matched intervention cohorts were 15.4% and 19.2%, respectively. CONCLUSION Intervention for low-grade intracranial dAVFs achieves superior obliteration rates compared to conservative management, but it fails to improve neurological or functional outcomes. Our findings do not support the routine treatment of low-grade dAVFs.

OBJECTIVE Radiation-induced meningiomas (RIMs) are associated with aggressive clinical behavior. Stereotactic radiosurgery (SRS) is sometimes considered for selected RIMs. The authors investigated the effectiveness and safety of SRS for the management of RIMs. METHODS From 12 institutions participating in the International Radiosurgery Research Foundation, the authors pooled patients who had prior cranial irradiation and were subsequently clinically diagnosed with WHO grade I meningiomas that were managed with SRS. RESULTS Fifty-two patients underwent 60 SRS procedures for histologically confirmed or radiologically suspected WHO grade I RIMs. The median ages at initial cranial radiation therapy and SRS for RIM were 5.5 years and 39 years, respectively. The most common reasons for cranial radiation therapy were leukemia (21%) and medulloblastoma (17%). There were 39 multiple RIMs (35%), the mean target volume was 8.61 ± 7.80 cm 3 , and the median prescription dose was 14 Gy. The median imaging follow-up duration was 48 months (range 4–195 months). RIM progressed in 9 patients (17%) at a median duration of 30 months (range 3–45 months) after SRS. Progression-free survival at 5 years post-SRS was 83%. Treatment volume ≥ 5 cm 3 predicted progression (HR 8.226, 95% CI 1.028–65.857, p = 0.047). Seven patients (14%) developed new neurological symptoms or experienced SRS-related complications or T2 signal change from 1 to 72 months after SRS. CONCLUSIONS SRS is associated with durable local control of RIMs in the majority of patients and has an acceptable safety profile. SRS can be considered for patients and tumors that are deemed suboptimal, poor surgical candidates, and those whose tumor again progresses after removal.

Abstract BACKGROUND Facial nerve schwannomas are rare, challenging tumors to manage due to their nerve of origin. Functional outcomes after stereotactic radiosurgery (SRS) are incompletely defined. OBJECTIVE To analyze the effect of facial nerve segment involvement on functional outcome for these tumors. METHODS Patients who underwent single-session SRS for facial nerve schwannomas with at least 3 mo follow-up at 11 participating centers were included. Preoperative and treatment variables were recorded. Outcome measures included radiological tumor response and neurological function. RESULTS A total of 63 patients (34 females) were included in the present study. In total, 75% had preoperative facial weakness. Mean tumor volume and margin dose were 2.0 ± 2.4 cm 3 and 12.2 ± 0.54 Gy, respectively. Mean radiological follow-up was 45.5 ± 38.9 mo. Progression-free survival at 2, 5, and 10 yr was 98.1%, 87.2%, and 87.2%, respectively. The cumulative proportion of patients with regressing tumors at 2, 5, and 10 yr was 43.1%, 63.6%, and 63.6%, respectively. The number of involved facial nerve segments significantly predicted tumor progression ( P = .04). Facial nerve function was stable or improved in 57 patients (90%). Patients with involvement of the labyrinthine segment of the facial nerve were significantly more likely to have an improvement in facial nerve function after SRS ( P = .03). Hearing worsened in at least 6% of patients. Otherwise, adverse radiation effects included facial twitching (3 patients), facial numbness (2 patients), and dizziness (2 patients). CONCLUSION SRS for facial nerve schwannomas is effective and spares facial nerve function in most patients. Some patients may have functional improvement after treatment, particularly if the labyrinthine segment is involved.

OBJECTIVEThe goal of this study was to evaluate the outcomes of Gamma Knife stereotactic radiosurgery (SRS) when used for patients with intractable idiopathic glossopharyngeal neuralgia.METHODSSix 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.RESULTSThe 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.CONCLUSIONSStereotactic 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.

Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5–220 months). Results Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression–free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression. Conclusions Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.

Object The aim of this study was to evaluate the outcomes of Gamma Knife surgery (GKS) when used for patients with intractable cluster headache (CH). Methods Four participating centers of the North American Gamma Knife Consortium identified 17 patients who underwent GKS for intractable CH between 1996 and 2008. The median patient age was 47 years (range 26–83 years). The median duration of pain before GKS was 10 years (range 1.3–40 years). Seven patients underwent unsuccessful prior surgical procedures, including microvascular decompression (2 patients), microvascular decompression with glycerol rhizotomy (2 patients), deep brain stimulation (1 patient), trigeminal ganglion stimulation (1 patient), and prior GKS (1 patient). Fourteen patients had associated autonomic symptoms. The radiosurgical target was the trigeminal nerve (TN) root and the sphenopalatine ganglion (SPG) in 8 patients, only the TN in 8 patients, and only the SPG in 1 patient. The median maximum TN and SPG dose was 80 Gy. Results Favorable pain relief (Barrow Neurological Institute Grades I–IIIb) was achieved and maintained in 10 (59%) of 17 patients at a median follow-up of 34 months. Three patients required additional procedures (repeat GKS in 2 patients, hypothalamic deep brain stimulation in 1 patient). Eight (50%) of 16 patients who had their TN irradiated developed facial sensory dysfunction after GKS. Conclusions Gamma Knife surgery for intractable, medically refractory CH provided lasting pain reduction in approximately 60% of patients, but was associated with a significantly greater chance of facial sensory disturbances than GKS used for trigeminal neuralgia.