Faculty Bibliography

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.

BACKGROUND:Brain arteriovenous malformations (AVMs) are abnormal connections between feeding arteries and draining veins, associated with significant risks of haemorrhage, seizures and other neurological deficits. Preoperative embolization is commonly used as an adjunct to microsurgical resection, with the aim of reducing intraoperative complications and improving outcomes. However, the efficacy and safety of this approach remain controversial. METHODS:This study is a subanalysis of the Multicenter International Study for Treatment of Brain AVMs consortium. We retrospectively analysed 486 patients with brain AVMs treated with microsurgical resection between January 2010 and December 2023. Patients were divided into two groups: those who underwent microsurgery alone (n=245) and those who received preoperative embolization, followed by microsurgery (n=241). Propensity score matching was employed, resulting in 288 matched patients (144 in each group). The primary outcomes were rates of complete AVM obliteration and functional outcomes (measured by the modified Rankin Scale (mRS)). Secondary outcomes included complication rates, mortality, hospital length of stay and postsurgical rupture. RESULTS:After matching, the complete obliteration rate was 97% with no significant difference between the microsurgery-only group and the preoperative embolization group (p=0.12). The proportion of patients with an mRS score of 0-2 at the last follow-up was similar in both groups (83% vs 84%; p=0.67). The median hospital stay was significantly longer for the embolisation group (9 days vs 7 days; p=0.017). Complication rates (24% vs 22%; p=0.57) and mortality rates (4.9% vs 2.1%; p=0.20) were comparable between the two groups. No significant differences were observed in postsurgical rupture, recurrence or retreatment rates. CONCLUSIONS:In this large multicentre study, preoperative embolization did not significantly improve AVM obliteration rates, functional outcomes or reduce complications compared with microsurgery alone.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Gynecological cancers represent 10% to 15% of cancers in women, but brain metastases (BM) are uncommon, with limited evidence regarding their management. This study investigates the role of stereotactic radiosurgery (SRS) for BM from primary gynecological cancers. METHODS:Institutions of the International Radiosurgery Research Foundation participated in this study. Inclusion criteria required histological diagnosis of epithelial ovarian, cervical, or endometrial cancer, SRS between 2000 and 2020, and at least 1 imaging or clinical follow-up. RESULTS:A total of 276 patients having SRS for 977 BM were included. Median age at SRS was 62 years (IQR, 55-70). Primary cancer origin was ovarian in 128 (46%), cervical in 43 (16%), and endometrial in 105 patients (38%). Median Karnofsky Performance Scale was 80%, and systemic disease was active in 124 (45%) of patients. A median of 1 metastasis was treated (IQR, 1-3) per patient. Median individual metastasis volume was 0.27 cc (IQR, 0.05-1.59 cc). The majority (91%) received single-fraction SRS, using a median margin dose of 18 Gy (IQR, 16-20 Gy). Actuarial overall survival was 77%, 65%, and 44% at 6, 12, and 24 months, respectively. Predictors of worsened survival included older age, cervical and endometrial primary, previous whole-brain radiation therapy (WBRT), active systemic disease, worsened Karnofsky Performance Scale, absence of subsequent surgery, and increasing number of BM. Actuarial local control was 94% at 6 months, 89% at 12 months, and 78% at 24 months. Previous SRS or WBRT, tumor bed treatment, and cervical histology increased the risk of local failure. New remote BM and leptomeningeal dissemination occurred in 44% and 11% of patients, respectively. Adverse radiation effects (ARE) occurred in 13% of cases but were symptomatic in only 3%. Previous WBRT or SRS and increased tumor diameter increased the risk of ARE. CONCLUSION/CONCLUSIONS:SRS is an effective management for BM from gynecological cancers with low risks of symptomatic ARE.

BACKGROUND:There is a paucity of data on treatment outcomes following stereotactic radiosurgery (SRS) for brain metastases from sarcoma primaries. METHODS:The International Radiosurgery Research Foundation member-sites were queried for patients with brain metastases from sarcoma primaries treated with SRS. Overall survival (OS) and local control (LC) were calculated via Kaplan-Meier analysis. Univariate analyses examined prognostic factors associated with LC and OS via log-rank t-tests and multivariate analyses (MVA) via Cox proportional hazards model. RESULTS:A total of 146 patients with 309 brain metastases were identified. Two-hundred and thirty lesions were treated with single-fraction SRS with a median dose of 20 Gy (15-24 Gy). Ninety-five patients had extracranial metastases, including 75 oligometastatic patients. One- and 2-year OS and LC rates were 47.7% and 37.3%, and 78.3% and 62.2%, respectively. On univariate analyses, superior 1-year OS was noted among leiomyosarcomas (69.7% vs. 42.6%; p = .02) with poorer outcomes among pleomorphic histologies (10.5% vs. 50.7%; p = .002). Pleomorphic histologies were associated with poorer OS on MVA (hazard ratio [HR], 3.13; p = .006). On MVA, LC was inferior among patients of age ≥45 years (HR, 3.78; p < .001) and superior among leiomyosarcomas (HR, 0.31; p = .03). OS was prognosticated based on adverse factors (ie, nonleiomyosarcoma histology and progressive extracranial metastases). Two-year OS for patients with and without adverse features were 78.6% and 31.5%, respectively. CONCLUSIONS:LC outcomes were driven by histology and age with superior LC among leiomyosarcomas and patients of age <45 years. OS was driven by nonleiomyosarcoma histology and the presence of progressive extracranial disease.