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Historically, it is stated that large intracranial tumors, herein defined as a maximum dimension of ≥3 cm or tumor volume ≥14.2 cm3, are not candidates for stereotactic radiosurgery (SRS). We report outcomes of patients with large benign intracranial tumors treated with SRS. With institutional review board approval, we retrospectively identified 74 patients with large benign intracranial tumors (59 meningiomas, 9 vestibular schwannomas, and 6 glomus jugulare tumors) treated with robotic SRS (2007–2018). Patients received definitive SRS in 47.3% of the cases, adjuvant to surgical resection in 44.6%, and salvage after past radiation treatment in 8.1%. A median tumor volume of 16.0 cm3 (range, 10.1–65.5 cm3) received a median dose of 24.0 Gy (range, 14.0–30.0 Gy) in a median of 3 fractions (range, 1–5), for a median single fraction equivalent dose (with alpha/beta of 3) of 14.8 Gy (range, 11.3–18.0 Gy). The Kaplan-Meier estimate of tumor local control (LC) was calculated from date of SRS. With a median clinical follow-up of 32.8 months (range, 0.6–125.9 months) and median radiologic follow-up of 28.5 months (range, 0.6–121.4 months), LC was 96.5% (95% confidence interval, 92.4%–100%) at 3 years and 91.7% (95% confidence interval, 87.6%–95.7%) at 5 years. Adverse radiation effect (ARE) was seen in 10 patients (13.5%) at a median of 13.5 months (range, 7.8–34.5 months). ARE occurred in 9% of those with prior treatment compared with 5% who were radiation-naïve (P = 0.23). With 236.4 person-years of follow-up, no secondary malignancies were seen. Despite the historical adage, we find that SRS provides high rates of LC for these large tumors, with rates of ARE similar to historical reports of SRS for smaller benign tumors. [ABSTRACT FROM AUTHOR]

Gross total resection of large intracranial meningiomas (LIMs) can be challenging and cause significant morbidity and mortality. The aim of this systematic review is to determine the clinical effectiveness and safety of stereotactic radiosurgery (SRS) either as primary or adjuvant therapy for LIMs with tumors ≥2.5 cm in maximum dimension (tumor volume ≥8.1 cm3). A total of 452 tumors in 496 patients (350 female [69.3%] and 146 male [30.6%]) with median age 60 years (48–65 years) were included. The median tumor volume at the time of diagnosis was 16.7 cm3 (10–53.3 cm3). The tumors typically were located in the skull base (77.2%), whereas only 14.6% were in the supratentorial space. The median follow-up after SRS was 54 months (18–90 months). In total, 87.8% of patients were treated with single-session (SS) Gamma Knife radiosurgery (GKS), whereas the remaining 12.1% patients received non-SS GKS. Of 452 LIMs assessed for clinical response, 45.1% showed improvement and 15.7% deteriorated after SRS. Radiographic tumor control at last follow-up (2–7.5 years) ranged from 84% to 100%. Overall, radiation-induced toxicity occurred in 23% of patients, with the most common adverse effect being cranial nerve neuropathy (5.5%) and peritumoral edema (5.3%). Subgroup analysis revealed that there is 2-fold greater likelihood of improvement in clinical symptoms in patients with non-SS GKS than SS GKS (odds ratio 2.47; 95% confidence interval 1.38–4.44; P = 0.002). SRS is safe and effective in the treatment of LIMs as primary or adjuvant treatment. Further prospective studies are required to validate our results. [ABSTRACT FROM AUTHOR]

Magnetic particle imaging (MPI) is a novel radiation-free tomographic imaging method that provides a background-free, signal attenuation–free, direct quantification of the spatial distribution of superparamagnetic iron-oxide nanoparticles (SPIONs) with high temporal resolution (milliseconds), high spatial resolution (<1 mm), and extreme sensitivity (μmol). The technique is based on nonlinear magnetization of the SPIONs when exposed to an oscillating magnetic field. MPI was first described in 2001. Since then, the technique has been applied to experimental imaging of diseases affecting different organs in the human body. The aim of this paper is to review the potential applications of MPI in the field of neurosurgery. A nonsystematic review of the existing literature on the use of MPI in neurosurgical diseases was performed. MPI has been used for the detection of locoregional invasion of brain tumors, tracking, and monitoring the viability of neural stem cells implanted for neuroregenerative purposes, diagnosis of cerebral ischemia, and diagnosis and morphofunctional assessment of brain aneurysms. MPI is at a preclinical stage. In the future, human-sized MPI scanners, along with the optimal toxicity profile of SPIONs will allow diagnostic applications in neurosurgical diseases. [ABSTRACT FROM AUTHOR]

Trigeminal neuralgia (TN) is a paroxysmal, unilateral, brief, shock-like pain in ≥1 divisions of the trigeminal nerve. It can result from multiple causes; however, TN secondary to stroke is very rare. We present the case of TN secondary to pontine infarction treated with incremental doses of neuropathic pain medication for >5 years before conservative management failed. He was then treated with stereotactic radiosurgery (SRS). Additionally, we conducted a systematic review using standard PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines for all the cases of TN with brainstem stroke from 1976 to 2022. Our patient was an 82-year-old man. Magnetic resonance imaging demonstrated a pontine lesion consistent with stroke. The Barrow Neurological Institute (BNI) score at presentation was 5. He received a marginal dose of 60 Gy to the 80% isodose line in a single fraction to a volume of 0.05 cm3. The immediate post-treatment BNI score was 0 and remained at 0 for 3 months, when he experienced recurrence. The recurrence was treated with oxcarbazepine. His pain remained well controlled with a lower dose of oxcarbazepine, and he had no adverse effects at 1 year of follow-up with a BNI score of 3. The systemic review identified 21 case reports with a combined cohort of 25 patients with TN secondary to stroke. Only 3 patients were treated with SRS, 2 of whom reported symptom improvement at 6 months and 8 months of follow-up with no adverse events. Our case and literature review demonstrate durable and effective treatment with SRS, which can be considered a safe and effective treatment option for patients with stroke-associated TN. [ABSTRACT FROM AUTHOR]

Choroid plexus papillomas (CPPs) are rare intraventricular brain tumors derived from the epithelium of the choroid plexus. Gross total resection has traditionally been considered curative, but residual tumor or recurrence remains possible. Stereotactic radiosurgery (SRS) has become a more important strategy for subtotally resected and recurrent tumors. The evidence-based rationale of SRS treatment for residual or recurrent CPP in adult patients is still lacking because of the rarity of the disease. We retrospectively reviewed the cases of histopathologically confirmed patients with residual or recurrent CPP treated with SRS at our institute in the adult population between 2005 and 2022. Three patients, with 5 lesions, were identified, with a median age of 63 years. Patients presented initially with hydrocephalus-related symptoms, although ventriculomegaly was noted in only 1 patient radiographically. The tumor location was most commonly in the fourth ventricle or along the foramen of Luschka. Treatment was delivered in a single fraction in 4 lesions and in 3 fractions in 1 patient. The median follow-up was 26 months. The local tumor control rate for the lesions was 80%. One patient developed a new lesion outside the SRS field, and 1 lesion developed progression without the need for subsequent treatment. There was no significant shrinkage of the lesions radiographically. None of the patients showed radiation-related adverse events. No patients required surgical management after SRS treatment at our institution. Based on the literature review, our case series was the second largest retrospective series from a single institution on SRS for recurrent or residual CPP. SRS for patients with recurrent or residual CPP was a safe and effective treatment modality in this case series. Larger studies are encouraged to validate the role of SRS in the treatment of recurrent or residual CPP. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration. Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990–2020 and had pre- and post-treatment audiograms. Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12–60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS. Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing. [ABSTRACT FROM AUTHOR]

Langerhans cell histiocytosis (LCH) is a rare idiopathic disease characterized by the clonal proliferation of Langerhans histiocytes in various parts of the body and capable of leading to organ damage and tumor formation. Reports of cranial LCH in the adult population are extremely rare. Although surgery remains the preferred option for localized LCH lesions, the role of stereotactic radiosurgery (SRS) is emerging. To retrospectively review a rare case series to determine the safety and effectiveness of SRS for patients with localized cranial LCH. We retrospectively reviewed histopathologically confirmed cases of localized cranial LCH treated with SRS at our institute in the adult population between January 2005 and September 2022. Five patients were identified with a median age of 34 years (19–54 years). The tumor location was in the pituitary stalk in 3 patients, the orbit in one patient, and the parietal skull in one patient. The median target volume was 2.8 cc (range: 0.37–6.11). Treatment was delivered in a single fraction in 4 patients (median margin dose of 8 Gy, range: 7–10 Gy) and in 3 fractions (22.5 Gy) in 1 patient. The median follow-up was 12 years (range: 4–17). None of the patients required craniotomy for tumor debulking before or after SRS. The local tumor control rate for the lesions was 100%. All 3 patients with LCH in the pituitary stalk had diabetes insipidus at the initial presentation and developed panhypopituitarism after SRS. Diabetes insipidus was not improved after SRS. The other 2 patients presented no adverse radiation effects. Based on the literature review, our case series was the largest retrospective series on SRS for localized cranial LCH, with the longest median follow-up. SRS for patients with localized cranial LCH was a safe and effective treatment modality in this case series. Larger studies are encouraged to validate the role of SRS in the treatment of localized cranial LCH. [ABSTRACT FROM AUTHOR]

Background There is limited information on O 6 -methylguanine DNA methyltransferase (MGMT) status, extent of surgical resection, and its impact on overall outcomes in patients with glioblastoma (GBM). Methods After institutional review board approval, 233 newly diagnosed patients with GBM with known MGMT status (2009–2015) were included in our analysis. Clinical, imaging, and follow-up data were collected from the database. Overall survival (OS) and progression-free survival (PFS) were the primary and secondary end points, respectively. Results Of patients, 51.9% were younger than 65 years and 44.2% were noted to have promoter methylation of MGMT. Median residual tumor volume was 1.1 cm 3 and extent of complete resection of enhancing tumor on imaging was 96%. Estimated median OS and PFS were 10.9 months and 5.4 months, respectively. MGMT status was an independent predictor of PFS (hazard ratio [HR], 0.52; P = 0.005) but only marginally associated with OS ( P = 0.059). In MGMT methylated patients, extent of resection (≥86%) and good performance status (Karnofsky Performance Status ≥70) were independently associated with PFS and OS, respectively (PFS: HR, 0.21; P = 0.015; OS: HR, 0.05; P = 0.002). In MGMT promoter unmethylated patients, extent of resection (≥86%) was independently associated with OS ( P = 0.039). Concurrent chemoradiotherapy was associated with OS/PFS irrespective of age and MGMT status. Conclusions Greater extent of resection of enhancing tumor was associated with improved PFS in MGMT promoter methylated patients, OS regardless of MGMT status. Elderly patients with methylated MGMT promoter were found to have improved PFS whereas younger patients had improved OS with MGMT promoter methylated status. [ABSTRACT FROM AUTHOR]