Comparison of preoperative versus postoperative treatment dosimetry plans of single-fraction stereotactic radiosurgery for surgically resected brain metastases.

OBJECTIVE: Stereotactic radiosurgery (SRS) for operative brain metastasis (BrM) is usually administered 1 to 6 weeks after resection. Preoperative versus postoperative timing of SRS delivery related to surgery remains a critical question, as a pattern of failure is the development of leptomeningeal disease (LMD) in as many as 35% of patients who undergo postoperative SRS or the occurrence of radiation necrosis. As they await level I clinical data from ongoing trials, the authors aimed to bridge the gap by comparing postoperative with simulated preoperative single-fraction SRS dosimetry plans for patients with surgically resected BrM. METHODS: The authors queried their institutional database to retrospectively identify patients who underwent postoperative Gamma Knife SRS (GKSRS) after resection of BrM between January 2014 and January 2021. Exclusion criteria were prior radiation delivered to the lesion, age < 18 years, and prior diagnosis of LMD. Once identified, a simulated preoperative SRS plan was designed to treat the unresected BrM and compared with the standard postoperative treatment delivered to the resection cavity per Radiation Therapy Oncology Group (RTOG) 90-05 guidelines. Numerous comparisons between preoperative and postoperative GKSRS treatment parameters were then made using paired statistical analyses. RESULTS: The authors' cohort included 45 patients with a median age of 59 years who were treated with GKSRS after resection of a BrM. Primary cancer origins included colorectal cancer (27%), non-small cell lung cancer (22%), breast cancer (11%), melanoma (11%), and others (29%). The mean tumor and cavity volumes were 15.06 cm3 and 12.61 cm3, respectively. In a paired comparison, there was no significant difference in the planned treatment volumes between the two groups. When the authors compared the volume of surrounding brain that received 12 Gy or more (V12Gy), an important predictor of radiation necrosis, 64% of patient plans in the postoperative SRS group (29/45, p = 0.008) recorded greater V12 volumes. Preoperative plans were more conformal (p < 0.001) and exhibited sharper dose drop-off at the lesion margins (p = 0.0018) when compared with postoperative plans. CONCLUSIONS: Comparison of simulated preoperative and delivered postoperative SRS plans administered to the BrM or resection cavity suggested that preoperative SRS allows for more highly conformal lesional coverage and sharper dose drop-off compared with postoperative plans. Furthermore, V12Gy was lower in the presurgical GKSRS plans, which may account for the decreased incidence of radiation necrosis seen in prior retrospective studies.

Clinical Implications of Pituitary Adenomas Exhibiting Dual Transcription Factor Staining: A Case Series of 27 Patients.

OBJECTIVE: According to the 2017 World Health Organization classification of neuro-endocrine tumors, pituitary adenomas (PAs) are classified according to immunoexpression of the pituitary-specific transcription factors (TFs). A small subset of PAs exhibit multiple TF staining on immunohistochemistry and we present a series of 27 pathologically-confirmed cases of dual TF staining PAs (dsTF-PAs), and report clinically relevant implications. METHODS: A retrospective chart review of a multi-institutional database of patients with PAs surgically resected between 2008-2021 was performed. PAs expressing immunopositivity 2+ TFs. Patient demographics, neuro-imaging characteristics, histopathologic findings, and clinical data were collected. RESULTS: Twenty-seven patients had pathologically verified dsTF-PAs, of whom 17 were female (63%), with ages ranging from 20-84 years. Twenty-three (85.2%) patients harbored functional PAs, with acromegaly being the most common functional subtype (86.4%). The most common combination of TFs within a single tumor was PIT-1/SF-1 (85.2%). Six PAs exhibited Knosp cavernous sinus invasion grades of 3 or 4 and the Ki-67 labeling index was ≥3% in 6 patients (24.0%) and all stained for PIT-1/SF-1. Hormonal remission was achieved in 78% of functional dsTF-PAs. No PAs showed evidence of recurrence or progression over the mean follow-up period of 28.5 months. CONCLUSIONS: PAs exhibiting dsTF-PAs represent a small but clinically relevant diagnostic subset of PAs according to the 2021 World Health Organization criteria, as a majority are GH-producing. Precise classification using TF staining plays a key role in understanding the biology of these tumors. Favorable outcomes can be achieved in this subset of PAs with evolving TF classification.

Management of growth hormone-secreting pituitary adenomas causing acromegaly: a practical review of surgical and multimodal management strategies for neurosurgeons.

This review aimed to highlight the history, diagnostic criteria, preoperative prognostic factors, surgical management, and multimodal adjuvant therapies recommended to provide a comprehensive and multifaceted understanding of and clinical approach to treating growth hormone-secreting pituitary adenomas (GHPAs) in patients with acromegaly. The authors collated and reviewed published studies, many written by skull base neurosurgeons, endocrinologists, and radiation oncologists with expertise in pituitary adenoma management, to produce a practical and contemporary update pertaining to the optimal management of acromegaly for neurosurgeons. Acromegaly is a debilitating disease for which surgery can be curative in more than two-thirds of patients. Recent rates of hormonal remission by the authors' group and others following the resection of GHPAs are on the order of 70%-80%, and these increase to more than 85% with the addition of medical therapy in a minority of patients who do not achieve remission with surgery alone. Most tumors are accessible via a direct endoscopic endonasal transsphenoidal approach, which can be augmented with a variety of extended approaches to gain access to suprasellar, clival, and parasellar compartments as needed. Preoperative growth hormone levels, cavernous sinus invasion, and pituitary adenoma consistency are important factors in determining the extent of resection. In most patients with residual or recurrent disease, medical therapy (e.g., somatostatin analogs and dopamine agonists) can be used to help achieve hormonal remission. Repeat surgery can be safely performed in most cases if needed, whereas stereotactic radiosurgery is usually reserved for medically resistant tumors in surgically inaccessible compartments. The neurosurgeon has a primary and often definitive role in the management of acromegaly. The involvement of an integrated and multidisciplinary team consisting of experts from neurosurgery, otolaryngology, endocrinology, and radiation oncology optimizes the chances for a biochemical cure, even in large and aggressive GHPAs.

Tumor characteristics guiding selection of channel-based versus open microscopic approaches for resection of atrial intraventricular meningiomas: patient series.

BACKGROUND: Atrial intraventricular meningiomas (AIMs) are relatively rare and typically deep-seated tumors that can mandate resection. Compared with transsulcal or transcortical open microscopic approaches, port- or channel-based exoscopic approaches have facilitated a less invasive alternative of tumor access and resection. The authors present a case series of seven patients with AIMs who underwent open microscopic versus channel-based exoscopic resection by a senior neurosurgeon at their institution between 2012 and 2022 to understand patient and tumor features that lent themselves to selection of a particular approach. OBSERVATIONS: In the patients harboring three AIMs selected for channel-based resection, the average AIM diameter (2.9 vs 5.2 cm) was smaller, the AIMs were deeper from the cortical surface (2.5 vs 1.1 cm), and the patients had a shorter average postoperative length of stay (3.3 vs 5.8 days) compared with the four patients who underwent open resection. Gross-total resection was achieved in all cases. Complications for both groups included transient homonymous hemianopsia and aphasia. No recurrences were identified over the follow-up period. LESSONS: The authors demonstrate that channel-based exoscopic resection is safe and effective for AIMs 3 cm in diameter and over 2 cm deep. This may help guide neurosurgeons in future approach selection based on tumor features, including size/volume, location, and depth from cortical surface.

Endoscopic endonasal approach for MRI-Negative Cushing's microadenoma.

A 54-year-old male with a history of diabetes mellitus type 2 for 12 years and hypertension was seen in the clinic due to poorly controlled diabetes. Inferior petrosal sinus sampling (IPSS) confirmed Cushing's disease with primary adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma on the right. However, 3T and subsequent 7T MRI showed no visible tumor. An endoscopic transsphenoidal approach was selected to explore the pituitary gland and resect the presumed microadenoma. Tumor was identified in the lateral recess along the right medial cavernous sinus wall and gross-total resection (GTR) was performed. The normal pituitary gland was preserved, and the patient went into remission. The video can be found here: https://stream.cadmore.media/r10.3171/2023.4.FOCVID2324.

Adverse Radiation Effects.

Here we discuss the low risk of radiation-related complications after Leksell radiosurgery, as well as its diagnosis and management. Using multimodality imaging in the context of clinical suspicion of radiation injury clinicians can now start management with agents designed to reduce the progression of radiation vasculopathy. In more severe cases both medical and surgical management options can be offered.