Faculty Bibliography

BACKGROUND AND OBJECTIVES/OBJECTIVE:Upfront stereotactic radiosurgery (SRS) could be an option for nonfunctioning pituitary adenomas (NFPA) unsuitable for surgery. Only small series evaluate the results of upfront SRS; the aim of the study was to report patient outcomes from a large, international patient cohort. METHODS:The study evaluated tumor control and complications after single-session SRS in a multicentric cohort of untreated NFPA. RESULTS:In total, 132 patients (median age 51.2 [IQR: 27.1] years at SRS, median volume 2.1 [IQR: 2.9] cm3) were included. The probability of tumor control was 100% (95% CI: 100-100), 98.1% (95% CI: 94.6-100), and 92.4 (95% CI: 81.6-100) at 3, 5, and 8 years after SRS. The cumulative probability of new pituitary deficit was 11.7% (95% CI: 3.8-18.9), 24.4% (95% CI: 12.1-35.1), and 29.5% (95% CI: 12.1-26.9) at 3, 5, and 8 years, respectively. No new visual field defect occurred. Before SRS, 50 patients (37.9%) presented with a visual field defect with a complete improvement in 17 (34.7%), partial improvement in 12 (24.5%), and stability in 19 (38.8%) at a last follow-up of 2.2 (3.9) years. One patient (2.0%) worsened after SRS. Before SRS, 10 patients (7.6%) presented with an oculomotor nerve palsy. One patient (0.8%) developed a new transient nerve palsy. At a last follow-up of 2.5 (4.4) years, 5 patients (45.4 35.7%) had a stability of their palsy, 1 had a partial improvement (9.1%), and 5 (45.4%) had a complete improvement. CONCLUSION/CONCLUSIONS:Upfront SRS represents an option for appropriately selected patients with NFPA, and it exhibits a favorable efficacy and safety profile, but a longer follow-up is required. Visual improvement is low, and careful selection of patient is required.

Background Arteriovenous malformations (AVMs) in eloquent brain regions pose significant challenges due to the increased risk of neurologic deficits associated with treatment. Although stereotactic radiosurgery (SRS) and endovascular embolization are used as standalone approaches, their comparative outcomes in eloquent brain AVMs remain unclear. Purpose To directly compare the outcomes of standalone endovascular embolization versus SRS for patients with AVMs in the eloquent brain. Materials and Methods This retrospective multicenter study analyzed patients with AVMs located in eloquent brain regions treated with standalone SRS or embolization from January 2010 to December 2023 as part of the Multicenter International Study for Treatment of Brain AVMs, or MISTA, consortium. Angiographic outcomes were assessed using digital subtraction arterial angiography, MR angiography, or CT angiography. Propensity score weighting (PSW) was used to account for baseline differences. Results A total of 119 patients were included (median age, 35 years [IQR, 21-54 years]; 64 female), with 96 patients treated with SRS and 23 with embolization. SRS achieved 71% (61 of 86 patients) complete obliteration at last follow-up compared with 56% (10 of 18 patients) in the embolization group (odds ratio [OR], 1.95; P = .20) before adjustment. After PSW, SRS achieved higher odds of complete obliteration at last follow-up (OR, 15.58; P = .001) compared with embolization. Before PSW, the SRS group had higher rates of modified Rankin Scale (mRS) scores 0-2 at last follow-up (95% [86 of 91 patients] vs 71% [15 of 21 patients]; OR, 6.8; P = .004) and a lower rate of hemorrhagic complications (5.2% [five of 96 patients] vs 26% [six of 23 patients]; OR, 0.15; P = .005) compared with embolization. Mortality rates were 2.1% (two of 96) in the SRS group and 4.3% (one of 23) in the embolization group (OR, 0.46; P = .54). After PSW, there was no evidence of a difference between SRS and embolization in mRS scores 0-2 (OR, 2.04; P = .45) or hemorrhagic complications (OR, 0.60; P = .63). Conclusion SRS was associated with a higher obliteration rate compared with embolization in patients with eloquent brain AVMs, whereas there was no evidence of a difference in functional outcomes or complications after adjustment. © RSNA, 2025 See also the editorial by Russell in this issue.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The therapeutic approach for small- and medium-sized vestibular schwannoma (VS) with normal hearing function remains controversial, with limited comparative data regarding hearing outcomes after stereotactic radiosurgery (SRS) or observation (OBS). We evaluated the serviceable hearing preservation, loss of American Academy of Otolaryngology-Head and Neck Surgery class A hearing, and tumor control (TC) across individuals with Koos grade I and II VSs and normal hearing at presentation who underwent SRS or OBS. METHODS:In this multicenter international study, we retrospectively analyzed the hearing, radiological, and neurological outcomes of patients who underwent SRS (SRS group) or OBS (OBS group). The cohorts were matched using propensity scores based on age, sex, tumor volume, pure-tone average, and speech discrimination score at a 1:1 ratio without replacement. RESULTS:After matching, each group comprised 57 patients. The median follow-up was 49 and 37 months for the SRS and the OBS groups, respectively (P = .3). The 5- and 9-year serviceable hearing preservation rates in the SRS group were 76.2% and 42.4% vs 56.1% and 16.8% in the OBS group (P = .17). Class A preservation occurred in 57.9% (33/57) of the SRS and 52.6% (30/57) of the OBS cohorts (P = .70). Regarding the TC rates, SRS was associated with significantly higher TC rates (P < .0001). CONCLUSION/CONCLUSIONS:We found that SRS is significantly superior regarding TC and provided noninferior hearing outcomes compared with OBS in VS patients with American Academy of Otolaryngology-Head and Neck Surgery class A hearing at presentation. Therefore, we suggest performing SRS in individuals with VS and normal hearing function.

BACKGROUNDAND OBJECTIVE/UNASSIGNED:The authors compareocclusion rates in grade I-III AVMs in smokers and non-smokers, using propensity score matching (PSM). METHODS:The authors performed a subgroup analysis of the MISTA consortium, a multicenter registry that includes patients aged 1 to 89 years with AVMs treated between January 2010 and December 2023. Only grade I-III AVMs were included. PSM was used to control confounders. Primary endpoints included angiographic obliteration. RESULTS:A total of 353 patients with bAVMs, with a median age of 37, were included in this study: 236 were never smokers, and 117 were current or previous smokers. After 1:1 PSM of smokers and non-smokers, 33 matched pairs were obtained. The smokers were more likely to display complete obliteration at last imaging follow-up compared to non-smokers (57.6 % vs. 27.3 %;p < 0.01). The median time to last clinical(p = 0.45)and angiographic(p = 0.33)follow up was not statistically different between the two groups.There were no statistically significant differences between the two matched groups in the incidence of post-SRS edema (p = 0.23), post-treatment rupture (0 %), overall mortality (p = 0.31), and functional status at the last follow-up (p = 0.69). CONCLUSION/CONCLUSIONS:Individuals with a positive history of smoking are more likely to achieve complete obliteration of grades I-III bAVMs following SRS treatment. However, smokers do not differ from non-smokers in terms of the incidence of post-treatment rupture, overall mortality, or functional status at the last follow-up.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Arteriovenous malformations (AVMs) with perinidal aneurysms and single draining vein are associated with an elevated risk of rupture and increased procedural complexity. The role of preoperative embolization in this high-risk anatomical subset remains unclear. This study aimed to evaluate the safety and efficacy of microsurgery with preoperative embolization, compared with microsurgery alone in patients with such AVMs. METHODS:We conducted a multicenter retrospective analysis of an AVM registry from the MISTA (Multicenter International Study for Treatment of Brain AVMs) consortium and included AVMs with perinidal aneurysms and a single draining vein. Baseline characteristics, angiographic outcomes, functional outcomes, and complication rates were compared. Propensity score weighting (PSW) using the covariate balancing method was applied to adjust for baseline differences. RESULTS:Out of a total of 1919 patients, 65 met the inclusion criteria; 45 patients underwent preoperative embolization followed by microsurgery, and 20 underwent microsurgery alone. After adjustment, complete obliteration rates were similar between groups (OR 0.87, 95% CI 0.04 to 16.33, P=0.92), as were rates of functional independence at discharge and follow-up. Overall complication, symptomatic complication, and mortality rates did not differ significantly between groups. However, permanent complications were significantly lower in patients with preoperative embolization (OR 0.06, 95% CI 0.004 to 0.84, P=0.03). DISCUSSION/CONCLUSIONS:In patients with AVMs featuring perinidal aneurysms and single draining vein, preoperative embolization followed by microsurgery was associated with fewer permanent complications and no increase in adverse outcomes compared with microsurgery alone. However, given the small number of events, this finding should be interpreted cautiously.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Since the introduction of the Leksell Gamma Knife to North America in 1987, stereotactic radiosurgery (SRS) has increasingly been used for patients with intracranial meningiomas. We evaluated the evolving application and outcomes of meningioma patients managed with both primary and adjuvant SRS during a 35-year interval. METHODS:The authors reviewed the outcomes of meningioma patients (1229 female, 69.8%; 2220 tumors) who underwent single-fraction SRS from August 1987 to March 2022 and who had a minimum of 6-month follow-up. The rates of treated tumor control and overall survival up to 20 years after SRS were measured. Risk factors analyzed included age, sex, tumor volume, margin dose, Ki-67, anatomical location, and pre-SRS surgical resection. RESULTS:Primary SRS showed superior tumor control compared with adjuvant SRS after previous resection. Overall, 191 of 2220 patients (8.6%) had local progression at last follow-up with the 5-year, 10-year, 15-year, and 20-year tumor control rates were 92.1%, 88.3%, 84.1%, and 81.1%, respectively. The median overall survival after SRS was 17.4 years, and 2.6% of patients died related to meningioma progression. Patients treated so that ≥60% of the tumor received at least 16 Gy demonstrated significantly superior tumor control. Fifty-eight patients (3.3%) experienced symptomatic adverse radiation effects after SRS. CONCLUSION/CONCLUSIONS:SRS provided excellent local tumor control rates that extended beyond 20 years. Primary SRS was an effective strategy for patients with unresected or known WHO grade I meningiomas. Adjuvant SRS was an important option to enhance tumor control and survival in patients with residual or progressive tumors after resection.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Bone metastases, affecting more than 4.8% of patients with cancer annually, and particularly spinal metastases require urgent intervention to prevent neurological complications. However, the current process of manually reviewing radiological reports leads to potential delays in specialist referrals. We hypothesized that natural language processing (NLP) review of routine radiology reports could automate the referral process for timely multidisciplinary care of spinal metastases. METHODS:We assessed 3 NLP models-a rule-based regular expression (RegEx) model, GPT-4, and a specialized Bidirectional Encoder Representations from Transformers (BERT) model (NYUTron)-for automated detection and referral of bone metastases. Study inclusion criteria targeted patients with active cancer diagnoses who underwent advanced imaging (computed tomography, MRI, or positron emission tomography) without previous specialist referral. We defined 2 separate tasks: task of identifying clinically significant bone metastatic terms (lexical detection), and identifying cases needing a specialist follow-up (clinical referral). Models were developed using 3754 hand-labeled advanced imaging studies in 2 phases: phase 1 focused on spine metastases, and phase 2 generalized to bone metastases. Standard McRae's line performance metrics were evaluated and compared across all stages and tasks. RESULTS:In the lexical detection, a simple RegEx achieved the highest performance (sensitivity 98.4%, specificity 97.6%, F1 = 0.965), followed by NYUTron (sensitivity 96.8%, specificity 89.9%, and F1 = 0.787). For the clinical referral task, RegEx also demonstrated superior performance (sensitivity 92.3%, specificity 87.5%, and F1 = 0.936), followed by a fine-tuned NYUTron model (sensitivity 90.0%, specificity 66.7%, and F1 = 0.750). CONCLUSION/CONCLUSIONS:An NLP-based automated referral system can accurately identify patients with bone metastases requiring specialist evaluation. A simple RegEx model excels in syntax-based identification and expert-informed rule generation for efficient referral patient recommendation in comparison with advanced NLP models. This system could significantly reduce missed follow-ups and enhance timely intervention for patients with bone metastases.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Single-session stereotactic radiosurgery (SRS) has limited role for large arteriovenous malformations (AVM). Volume-staged SRS (VS-SRS) is used to optimize outcomes, but studies reporting results are limited. METHODS:This multicenter retrospective cohort of 378 patients from 21 centers reports results of VS-SRS for the entire AVM nidus. We report favorable outcome, obliteration, hemorrhage, and permanent symptomatic adverse radiation effect rates. RESULTS:The median age was 31 years (IQR: 19-44) at the first volume stage, with patients treated in 2-4 stages. The median total nidus volume was 21 cm3 (IQR: 13.9-30.1 cm3), and a median prescription dose of 17 Gy (IQR: 16-18 Gy) was used. The median radiographic and clinical follow-up were 48 and 55 months, respectively. Seventy-seven patients (20.4%) had a favorable outcome, with the 3-year and 5-year rates being 3.9% and 18%, respectively. 127 patients (33.6%) achieved obliteration, with the 3-year and 5-year rates being 6.8% and 26%, respectively. Obliteration rates of AVMs <15 cm3 were 81% and 31%, respectively. The latency period hemorrhage incidence rate was 3.02 cases per 100 patient-years; 52 patients (13.8%) had a bleed. Seventy-two patients (19%) had symptomatic adverse radiation effect; in 38 patients (10.1%), these were permanent. Total nidus volume, prescription dose at first stage, diffuse nidus, and prior hemorrhage were all independent affecting outcome rates. CONCLUSION/CONCLUSIONS:VS-SRS can be used to treat large AVMs as a standalone treatment. Obliteration rates and favorable outcomes are lower than that with smaller AVMs, and repeat treatment is often required. Optimizing treatment plans, by increasing prescription doses, reducing treatment volume at each stage, and increasing the number of stages, may lead to better outcomes.

PURPOSE/OBJECTIVE:Bladder cancer rarely metastasizes to the brain. This study was performed to evaluate stereotactic radiosurgery (SRS) for the management of bladder cancer brain metastases. METHODS:Cases of bladder cancer brain metastases treated with SRS were collected by members of the International Radiosurgery Research Foundation (IRRF) and outcome data was analyzed for patients with at least one clinical or imaging follow-up. RESULTS:103 patients received SRS for 301 brain metastases. Median age at SRS was 68 and 73.8% of patients were male. Median KPS was 80%. Median time from primary to brain metastases diagnosis was 18 months. At the time of SRS, 50% of patients had other systemic metastases. The median number of metastases treated was 1, and median cumulative SRS volume was 1.16 cc. Most patients had single fraction SRS using a median margin dose of 18 Gy. At the time of analysis, 9.7% of patients were alive. Median survival after SRS was 7 months. Local control was achieved for 89.3% of metastases, 42% of patients developed new remote brain metastases, and 4.9% had leptomeningeal dissemination. Subsequent management included repeat SRS in 21.7%, surgical resection in 8.8% and WBRT in 7.6% of patients. At last follow-up, 32.1% of patients had improvement of their symptoms, whereas 38.5% remained stable. Adverse radiation effects occurred in 4.3% of treated metastases. On multivariate analyses, KPS ≥ 80% and non-urothelial histology predicted improved survival, while absence of corticosteroid intake predicted longer tumor control. CONCLUSION/CONCLUSIONS:Bladder cancer brain metastases can be safely managed with SRS.