BACKGROUND AND OBJECTIVES:Separation surgery followed by stereotactic body radiation therapy (SBRT) for solid tumor malignancies metastatic to the spine has excellent durable 2-year local control rates. Preoperative embolization (PEm) is used as an adjunct to decrease operative blood loss for known hypervascular tumor histologies. Recent studies suggest potential benefits of PEm on local control and overall survival, but they involved heterogeneous tumor populations over time periods where systemic therapy was evolving rapidly. Therefore, we set out to determine the impact of PEm for metastatic spine tumors on a 2-year local control and overall survival in a histologically homogeneous cohort of patients with hypervascular tumor histologies. METHODS:This was a single-center, retrospective chart review from 2011 to 2022 at a quaternary cancer center for all patients with renal cell carcinoma, hepatocellular carcinoma, or thyroid cancer diagnosed with spinal metastatic disease who underwent surgical treatment followed by SBRT with or without PEm. RESULTS:Overall, 161 patients were included with 71 undergoing PEm (63 successful and 8 unsuccessful) and 90 not receiving PEm. The 8 who underwent angiogram but were not embolized were considered in the no PEm cohort. Between PEm and no PEm groups, there was no significant difference in age, sex, Eastern Cooperative Oncology Group, preoperative American Spinal Injury Association score, tumor histologies, number of adjacent segments involved, Spinal Instability Neoplastic Scale score, hospital length of stay, time from surgery to SBRT, radiation treatment dose (biological effective dose and equivalent dose in 2-gray fractions), or number of fractions ( P > .05 for all). The median overall survival was 18 months for both groups with no significant difference between PEm and no PEm ( P = .8). There was no significant difference in 12- and 24-month local control with rates of 94.8% and 91.7% for no PEm and 96.8% and 95.2% for the PEm group, respectively ( P = .7). CONCLUSION:PEm demonstrated no impact on local control or overall survival in patients with hypervascular spine metastases undergoing separation surgery followed by SBRT.

PURPOSE:To evaluate the safety and effectiveness of coil-only middle meningeal artery embolization (MMAE) for the treatment of subacute to chronic subdural hematoma (SDH) in patients with cancer. MATERIALS AND METHODS:A single-center retrospective analysis was performed of 30 patients with cancer with SDH, 12 of whom had bilateral hematomas, who underwent MMAE of the affected side(s) using coils alone between 2022 and 2025. Clinical and radiographic outcomes were evaluated, including hematoma resolution, change in SDH thickness, need for reoperation, and overall survival. RESULTS:Median SDH thickness declined from 12 mm (interquartile range [IQR], 9 mm) before embolization to 3.6 mm (IQR, 8.8 mm) on final imaging (Wilcoxon signed-rank z = 4.59, P < .001). A ≥50% reduction was observed in 56% of SDHs, and complete radiographic resolution was observed in 37%. One patient (3%) required surgical evacuation after MMAE. Seventeen patients (59%) died due to cancer progression during follow-up. Median survival was significantly longer among patients with reduced hematoma thickness at initial follow-up imaging (148 vs 29 days, log-rank P = .0002). CONCLUSIONS:Coil-only MMAE may be a safe and effective treatment option for SDH in patients with cancer. Reduction in hematoma thickness was associated with longer survival in this high-risk population.

BACKGROUND AND PURPOSE:18F-FDG PET/CT and conventional MRI are common first-line imaging modalities for assessment of osseous spinal lesions. Dynamic contrast-enhanced MR imaging (DCE-MRI) is an advanced technique that quantifies vascular perfusion parameters like vessel permeability (Ktrans ) and plasma volume (Vp ), which are markers of viable tumor. Although DCE-MRI and 18F-FDG PET/CT are individually recognized for tumor detection, comparisons between Vp and PET-obtained maximum standardized uptake value (SUVmax) have not been performed. This study evaluates the concordance between Vp and SUVmax in detecting pathologically confirmed, nontreated osseous spinal metastases. MATERIALS AND METHODS:Nontreated osseous spinal metastases biopsy-confirmed between February 2015 and January 2022 with available DCE-MRI and 18F-FDG PET/CT scans were retrospectively analyzed. Exclusion criteria included radiation therapy near lesions and therapy between scans. Mean Ktrans and Vp were obtained from DCE-MRI via the extended Tofts model and compared with PET SUVmax values. A Vp threshold of 2.10 and PET SUVmax thresholds of 2.00, 2.50, and 4.00 were used to detect metastases. Agreement was assessed via McNemar tests (α = .05). RESULTS:Eighty-five metastases across 69 patients (mean age: 64.15 [SD, 12.13] years; 35 men) were evaluated. At an SUVmax threshold of 2.00, Vp demonstrated a high agreement of 81.18% (69/85) with SUVmax in detecting biopsy-confirmed tumors. Agreement with other SUVmax thresholds was lower: 67.06% (57/85) for an SUVmax of 2.50 and 48.24% (41/85) for an SUVmax of 4.00, as expected. Vp identified the most metastases at 84, compared with 68, 56, and 40 for SUVmax thresholds of 2.00, 2.50, and 4.00, respectively (P < .001). CONCLUSIONS:Vp and SUVmax showed agreement in detecting osseous spinal metastases. However, when common thresholds for these metrics are applied, Vp exceeds SUVmax in identifying viable tumor. DCE-MRI plays a crucial role in detecting spinal metastases and, in some instances, more accurately detects biopsy-positive lesions compared with 18F-FDG PET/CT.

PURPOSE:Limited data are available on outcomes of patients with spinal metastases treated with separation surgery with postoperative stereotactic body radiation therapy. METHODS AND MATERIALS:This is a retrospective cohort study of 497 patients treated for 532 lesions between 2013 and 2024. We evaluated local failure (LF) and adverse events (hardware failure [HF] requiring surgical intervention, radiation myelitis [RM], and vertebral compression fracture [VCF]). Incidences of LF, VCF, RM, and HF were analyzed considering death as a competing risk. Dosimetric variables, including minimal biologically effective dose (BED) to the clinical target volume (CTV Dmin BED10), were obtained. Preoperative and postoperative epidural spinal cord compression (ESCC) scores were calculated based on preoperative magnetic resonance imaging and postoperative myelogram simulation. RESULTS:Median follow-up time among surviving patients was 74.5 months (95% CI, 70-94). Median overall survival was 14 months (95% CI, 13-17). The risk of LF (95% CI) at 1, 2, and 3 years was 7.7% (5.6%-10%), 10% (7.9%-13%), and 13% (10%-16%), respectively. At 2 years, cumulative incidences of VCF, RM, and HF requiring surgery were 2% (95% CI, 1%-3.5%), 1% (0.39%-2.3%), and 3.8% (2.4%-5.8%), respectively. On univariable and multivariable regression, CTV Dmin BED10 correlated with risk of LF (on multivariable regression, hazard ratio, 0.96; 95% CI, 0.93-0.99; P = .005). After excluding previously radiated lesions, postoperative ESCC ≤1C was associated with an approximately 2-times higher likelihood of achieving the median CTV Dmin BED10 than ESCC 2 (odds ratio, 2.06; 95% CI, 1.31-3.26; P = .002), whereas a postoperative ESCC ≤1B was not associated with higher odds of achieving the median CTV Dmin BED10 compared with ≥1C (odds ratio, 0.75; 95% CI, 0.50-1.11; P = .15). CONCLUSIONS:In this large series of separation surgery followed by spine stereotactic body radiation therapy, local control was excellent with few adverse events. Higher CTV minimum biological dose-enabled by postoperative ESCC ≤1C-was the strongest predictor of durable local control.

PURPOSE:We sought to characterize outcomes from a large institutional database of patients treated with 3-fraction spine stereotactic body radiation therapy (SBRT) after prior overlapping radiation therapy. METHODS AND MATERIALS:The primary outcome of interest was local failure (LF) in the treated lesion, defined based on magnetic resonance imaging. We also characterized toxicities such as vertebral compression fracture and radiation myelitis. RESULTS:There were 83 patients treated to 87 spinal lesions between 2014 and 2023. Median follow-up was 14.2 (IQR, 6-29.4) months, and median overall survival was 20.5 (95% CI, 16.5-29.9) months. Most lesions were treated with 27 Gy in 3 fractions (n = 78; 90%). Most lesions had been treated with prior conventionally fractionated radiation therapy (59%), and the most common histology was prostate cancer (n = 15; 17%). The 1- and 2-year LF rate was 8.4% (95% CI, 3.7%-16%) and 15% (95% CI, 8.1%-24%), respectively. On univariable analysis, lower minimum dose to the planning target volume (hazard ratio, 0.85, 95% CI, 0.74-0.99, P = .03) and colorectal, cholangio-, or hepatocellular carcinoma histology (hazard ratio 5.6, 95% CI, 1.11-28.4, P = .037) were associated with risk of LF. There was 1 case of radiation myelitis (1.3%) and 5 cases (5.5%) of vertebral compression fracture. CONCLUSION:Reirradiation with spine SBRT in 3 fractions appears safe and is associated with a 2-year local control rate of 85%. Lower planning target volume, lower minimum dose, and gastrointestinal histology were associated with increased risk of LF. Further work is needed to identify the optimal dose-fractionation regimen for reirradiation with spine SBRT.

PURPOSE:Little is known about the long-term outcomes of patients with spinal metastases treated with proton hypofractionated radiotherapy (pHFRT), particularly in the setting of re-irradiation (re-RT). METHODS:This is a retrospective cohort study of patients treated between 2015-2023 utilizing pHFRT (≤10 fractions). All patients received follow-up magnetic resonance imaging at least 1 month after treatment. Outcomes of interest included local failure (LF), defined radiographically, as well as long-term adverse events. RESULTS:A total of 52 patients treated to 58 lesions met inclusion criteria. Median follow-up after RT was 14 months (IQR 8-25). The most common dose-fractionation scheme was 40 Gy in 5 fractions (n=47, 81%). There were 10 cases of first-time RT utilizing protons (17%), whereas 25 courses (43%) were second-time re-RT, 19 courses (33%) were third-time re-RT and 4 courses (6.9%) were fourth-time re-RT. Median cumulative equivalent dose in 2-Gy fractions (EQD2) was 115 Gy (IQR 91-153). The 1-year LF rate was 10% (95% confidence interval (CI) 4-20%), and the 2-year LF rate was 22% (95% CI 12-35%). There were 5 grade (G) 3 adverse events, including radiation myelitis (1), esophageal fistula (1), esophageal stricture (1), wound dehiscence (1), and bowel necrosis (1). All G3 adverse events occurred in patients who received 3-4 overlapping courses of RT. There were no G4-5 adverse events. CONCLUSION:PHFRT is associated with excellent local control in this large cohort of heavily re-irradiated patients (81% re-RT). G3 adverse events were limited to patients who received 3-4 overlapping courses of RT.

Interventional neuro-oncology is an evolving subspecialty that leverages minimally invasive endovascular and percutaneous techniques to improve outcomes for patients with spine, brain, and head-neck tumours. While conventional interventions have historically focused on vascular pathologies such as stroke and aneurysms, interventional techniques in oncology are gaining prominence. This review explores the role of image-guided interventions in preoperative tumour embolization, middle meningeal artery embolization in thrombocytopenic cancer patients, management of head and neck hemorrhage, intra-arterial drug delivery, and spinal interventions. Through a synthesis of current evidence, we highlighted the growing importance of interventional techniques in neuro-oncology and discuss future advancements in image guidance, robotics, and targeted drug delivery.

ImportanceStereotactic body radiation therapy (SBRT) for spinal metastases improves symptomatic outcomes and local control compared to conventional radiotherapy. Treatment failure most often occurs within the epidural space, where dose is constrained by the risk of radiation myelitis (RM). Current constraints designed to prevent RM after spine SBRT are derived from limited data.ObjectiveTo characterize the risk of RM after spine SBRT and to update the dosimetric constraints for preventing it.Design, Setting, and ParticipantsThis cohort study was conducted in a single tertiary cancer care center with patients treated for spinal metastases from 2014 to 2023. All included participants had undergone spine SBRT, had a minimum of 1-month follow-up with magnetic resonance imaging (MRI), a maximal cord dose to a voxel (Dmax) greater than 0 Gy, and no overlapping prior radiotherapy. In all, 2051 patients received SBRT to 2835 spinal metastases (levels C1-L2) during the study period.ExposuresThree-fraction spine SBRT to a prescription dose of 27 to 36 Gy.Main Outcomes and MeasuresRM defined as radiographic evidence of spinal cord injury in the treatment field, classified as grade (G) 1 to G4 or G3 to G4 per the Common Terminology Criteria for Adverse Events, version 5.0. Multiple dosimetric parameters of the true spinal cord structure were assessed for an association with risk of RM to determine the important covariates associated with this toxicity.ResultsThe analysis included 1423 patients (mean [SD] age, 61.6 [12.9] years; 695 [48.8%] females and 728 [51.1%] males) who received SBRT for 1904 spinal metastases. Among them, 30 cases of RM were identified, 19 of which were classified as G3 to G4. Two years after SBRT, the rate of G1 to G4 RM was 1.8% (95% CI, 1.2%-2.5%) and the rate of G3 to G4 RM was 1.1% (95% CI, 0.7%-1.7%). The minimum dose to the 0.1 cm3 of spinal cord receiving the greatest dose (D0.1cc) was the most important covariate on univariable cause-specific hazards regression for RM (for G3 to G4: hazard ratio, 2.14; 95% CI, 1.68-2.72; P < .001). A true cord D0.1cc of 19.1 Gy and Dmax of 20.8 Gy estimated a 1.0% risk (95% CI, 0.3%-1.6% and 0.4%-1.6%, respectively) of G3 to G4 RM 2 years after SBRT.Conclusions and RelevanceThe findings of this cohort study indicate that a cord (myelogram or MRI-derived) D0.1cc constraint of 19.1 Gy and a Dmax constraint of 20.8 Gy correspond with a 1.0% risk of G3 to G4 RM at 2 years.

Significant advancements in cancer treatment have led to improved survival rates for patients, particularly in the context of spinal metastases. However, early detection and monitoring of treatment response remain crucial for optimizing patient outcomes. Although conventional imaging methods such as bone scan, PET, MR imaging, and computed tomography are commonly used for diagnosing and monitoring treatment, they present challenges in differential diagnoses and treatment response monitoring. This review article provides a comprehensive overview of the principles, applications, and practical uses of dynamic contrast-enhanced MR imaging and diffusion-weighted imaging in the assessment and monitoring of marrow-replacing disorders of the spine.

BACKGROUND AND OBJECTIVES:Pathological vertebral compression fractures (VCFs) cause significant morbidity in the population with cancer. Although both stabilization of fractures with kyphoplasty and pedicle screw fixation can alleviate pain and prevent neurological compromise in select patients, there are no criteria demarcating which patients can be treated with kyphoplasty alone vs pedicle screw fixation, particularly for those with intermediate spinal instability. The objective of this study was to identify predictors of kyphoplasty failure requiring subsequent surgical stabilization in patients with metastatic thoracolumbar VCFs. METHODS:Patients who underwent single or 2 level kyphoplasty for pathological VCFs between 2015 and 2020 were included in a retrospective analysis at a tertiary cancer center. The primary outcome measure was kyphoplasty failure, defined as return to the operating room for pedicle screw fixation. Hazard ratios (HR) were estimated in the competing risks setting. Thresholds for variables were identified where possible. RESULTS:Forty-two of 445 patients (9.8%) failed kyphoplasty, with an average time to failure of 318 days and a 5-year cumulative incidence of 10.3% (95% CI: 7.5%-13.6%). We found focal kyphotic angle (HR 1.09, 95% CI: 1.05-1.12, P < .0001), Spinal instability neoplastic score (HR 1.16, 95% CI: 1.05-1.28, P = .03), spinal canal compromise (HR 1.05, 95% CI: 1.03-1.07, P < .0001), and posterior element involvement (HR 1.93, 95% CI: 1.03-5.63, P = .04) to be significantly associated with increased risk of kyphoplasty failure even after mutual adjustment in the multivariable setting. There were no significant associations between kyphoplasty failure and sex, age at kyphoplasty, anatomic location, or quality of bone lesion. CONCLUSION:Kyphoplasty failure in metastatic VCFs is associated with specific radiographic markers of spinal instability. Patients with spinal instability neoplastic score ≥11, posterior-element involvement, canal compromise, and significant kyphosis may benefit from up-front surgical stabilization with pedicle screws, particularly for patients with anticipated long-term survival.

Conventional MRI is currently the preferred imaging technique for detection and evaluation of malignant spinal lesions. However, this technique is limited in its ability to assess tumor viability. Unlike conventional MRI, dynamic contrast-enhanced (DCE) MRI provides insight into the physiologic and hemodynamic characteristics of malignant spinal tumors and has been utilized in different types of spinal diseases. DCE has been shown to be especially useful in the cancer setting; specifically, DCE can discriminate between malignant and benign vertebral compression fractures as well as between atypical hemangiomas and metastases. DCE has also been shown to differentiate between different types of metastases. Furthermore, DCE can be useful in the assessment of radiation therapy for spinal metastases, including the prediction of tumor recurrence. This review considers data analysis methods utilized in prior studies of DCE-MRI data acquisition and clinical implications.

Purpose Spine stereotactic body radiation therapy (SBRT) outperforms conventional radiation therapy in preventing local failure (LF). Data comparing dose-fractionation schemes on the likelihood of LF and vertebral compression fracture (VCF) are limited. Methods and Materials This is a retrospective cohort study of 1838 patients (2702 lesions) treated between 2014 and 2023 at a single institution with de novo spine SBRT. LF was defined as progressive disease on magnetic resonance imaging. VCF was defined as progressive or new fracture on magnetic resonance imaging without LF. Death was considered a competing risk. Results Median follow-up after SBRT for surviving patients was 25 months (IQR 13-43 months). Eleven hundred ninety-seven lesions (44%) received 27 Gy in 3 fractions, 931 (34%) received 30 Gy in 3 fractions, and 574 lesions (21%) received 24 Gy in 1 fraction. Three hundred nine treatment courses involved separation surgery (11%), and 311 lesions (11%) were epidural spinal cord compression score 2 to 3. For lesions treated with 24 Gy in 1 fraction, 30 Gy in 3 fractions, and 27 Gy in 3 fractions, 2-year LF rates (95% CI) were 7% (5%-9%), 11% (9%-13%), and 17% (15%-20%), respectively (P < .001). Two-year VCF rates (95% CI) requiring stabilization were 10% (8%-13%; 24 Gy in 1 fraction), 2% (1%-3%; 27 Gy in 3 fractions), and 3% (2%-5%; 30 Gy in 3 fractions) (P < .001). For the 3-fraction regimens specifically, 30 Gy was associated with a higher overall VCF rate (P = .022) and lower LF rate (P < .001), but there was no significant difference in the risk of VCF requiring intervention (P = .15). Univariable and multivariable regression revealed histologic-based differences in LF: 2-year LF rates were 8.6% (95% CI, 6.4%-11%) for class A lesions (prostate and breast cancers), 26% (95% CI, 20%-32%) for class C lesions (cholangio-, hepatocellular, and colorectal carcinoma), and 13% (95% CI, 12%-15%) for class B lesions (other histologies) (P < .001). For class B to C, epidural spinal cord compression 2 to 3 lesions (n = 261), surgery plus SBRT reduced LF compared to SBRT alone (7.9 vs 20% at 2 years, P = .051), though this did not reach statistical significance. Conclusions The preferred hypofractionated SBRT regimen—even for class A histologies—is 30 Gy in 3 fractions, offering superior local control with similar risk of VCF requiring intervention, compared to 27 Gy. For class B to C lesions with high-grade epidural disease, separation surgery prior to SBRT may improve local control.

PURPOSE:To determine whether driver gene alterations in metastatic non-small cell lung carcinoma (NSCLC) spine metastases are associated with local tumor control after radiotherapy (RT). METHODS:Patients with NSCLC who underwent RT for spine metastasis and tumor genetic profiling were ascertained. Associations between driver gene mutations incidence of local failure were analyzed, followed by competing risk analysis for significant associations. The results were validated using in vitro clonal survival assays of CRISPR-engineered NSCLC cell lines. RESULTS:A total of 181 patients were analyzed, with a median follow-up of 15.2 months (IQR, 8.0-31.9 months). The 3-year risk of local failure was 0.15 (95% CI, 0.10 to 0.20). Patients harboring NF1 or BRAF driver alterations experienced higher 3-year local failure rates (NF1: 0.33 [0.09-0.61] v 0.13 [0.09-0.19]; P = .002); BRAF: 0.31 [0.08-0.57] v 0.13 [0.09-0.19]; P = .04). NF1 loss-of-function mutations conferred radioresistance in one of two NSCLC cell lines tested in vitro. Based on the convergence of NF1 and BRAF signaling, the RAS-mitogen-activated protein kinase (MAPK) pathway was further interrogated. KRAS mutations overall were not associated with local failure. However, comutation of KRAS/TP53 exhibited a trend toward elevated 3-year local failure, 0.31 (0.11-0.55) versus 0.13 (0.08 v 0.19), P = .05. RAS-MAPK pathway driver alterations accounted for 53% of all local failures (P < .0001) and showed an elevated 3-year risk of local failure (0.36 [0.2-0.51] v 0.09 [0.05-0.15]; P < .001), including when treated with stereotactic body RT (0.28 [0.1-0.5] v 0.05 [0.02-0.11]; P = .001). CONCLUSION:Driver alterations in the RAS-MAPK signaling pathway confer radioresistance in metastatic NSCLC. These genetic alterations may serve as biomarkers to personalize RT strategies or as targets to enhance radiosensitivity.

Study Design. This is a retrospective, cross-sectional study. Objective. The primary aim was to identify the diagnostic yield of spine magnetic resonance imaging (MRI) in detecting malignant pathology in cancer patients with back pain. We also sought to evaluate the role of MRI extent ( i.e. regional vs. total) in identifying malignant pathology. Summary of Background Data. No prior study has systematically investigated the yield of spine MRI in a large cohort of cancer patients. Methods. Spine MRI reports from 2017 to 2021 for back pain (acute and nonspecified chronicity) in cancer patients were reviewed to identify clinically relevant findings: malignant (1) epidural, (2) leptomeningeal, (3) intramedullary, (4) osseous disease, and (5) fracture. Logistic regression was used to evaluate the association between MRI extent and the presence of cancer-related findings. For patients with multiple MRIs, short-interval scans (≤4 mo) were evaluated to assess the yield of repeat imaging. Results. At least one cancer-related finding was identified on 52% of 5989 spine MRIs ordered for back pain and 57% of 1130 spine MRIs ordered specifically for acute back pain. The most common pathology was malignant osseous disease (2545; 43%). Across all five categories, most findings (77%–89%) were new/progressive. Odds of identifying a finding were significantly higher with total versus regional spine MRIs ( P <0.001). Although only 14 patients had a positive regional MRI followed shortly by a positive total spine MRI, most of these repeat total spine MRIs (78%) identified findings outside the scope of the initial regional scan. Twenty-one patients had both computed tomography and MRI within 30 days of each other; eight (38%) had compression fractures appreciated on MRI but not on computed tomography. Conclusions. Our findings suggest imaging the total spine in cancer patients with back pain given higher odds of identifying malignant pathology and instances of capturing otherwise not visualized disease. Further work is warranted to confirm these findings.

BACKGROUND AND PURPOSE:A retrospective single-center analysis of the safety and efficacy of reirradiation to 40 Gy in 5 fractions (reSBRT) in patients previously treated with stereotactic body radiotherapy to the spine was performed. METHODS:We identified 102 consecutive patients treated with reSBRT for 105 lesions between 3/2013 and 8/2021. Sixty-three patients (61.8%) were treated to the same vertebral level, and 39 (38.2%) to overlapping immediately adjacent levels. Local control was defined as the absence of progression within the treated target volume. The probability of local progression was estimated using a cumulative incidence curve. Death without local progression was considered a competing risk. RESULTS:Most patients had extensive metastatic disease (54.9%) and were treated to the thoracic spine (53.8%). The most common regimen in the first course of stereotactic body radiotherapy was 27 Gy in 3 fractions, and the median time to reSBRT was 16.4 months. At the time of simulation, 44% of lesions had advanced epidural disease. Accordingly, 80% had myelogram simulations. Both the vertebral body and posterior elements were treated in 86% of lesions. At a median follow-up time of 13.2 months, local failure occurred in 10 lesions (9.5%). The 6- and 12-month cumulative incidences of local failure were 4.8% and 6%, respectively. Seven patients developed radiation-related neuropathy, and 1 patient developed myelopathy. The vertebral compression fracture rate was 16.7%. CONCLUSION:In patients with extensive disease involvement, reSBRT of spine metastases with 40 Gy in 5 fractions seems to be safe and effective. Prospective trials are needed to determine the optimal dose and fractionation in this clinical scenario.

Purpose  To assess the feasibility and safety of cone-beam computed tomography (CBCT) advanced navigation for optimizing intra-arterial chemotherapy infusion (IACI) in patients with skull base tumors. Materials and Methods  Retrospective review on 10 consecutive IACI procedures performed in five patients (four women, 1 man) over a 1-year period. The median age of the patients was 71 years (interquartile range: 34-74). During the procedures, a CBCT-based navigation software was employed to evaluate tumor perfusion and guide the infusion methods. Catheterization of the primary tumor feeding vessel was performed in seven cases when it originated from the external carotid artery, whereas a temporary balloon-assisted occlusion technique was utilized in the remaining three cases where the tumor was primarily fed by the internal carotid artery. Carboplatin, topotecan, and melphalan were injected over a 10-minute period. Fluoroscopy time, reference dose, and Kerma area product, which estimates effective dose, were analyzed. Results  The technical success rate was 100%, with a median procedure length of 82 minutes (79-90). The median fluoroscopy time was 11.3 minutes (9.4-16.9), reference dose was 93.5 mGy (62-256.5), and Kerma area product was 11.6 Gy.cm 2 (9.5-25.4). The median effective dose was 3.8 mSv (1.5-5.1). The median follow-up duration was 233.5 days (186.3-432). One severe adverse event was reported, involving a right brachial hematoma and brachiocephalic artery dissection related to catheterization through a type III aortic arch. Three patients exhibited disease progression, but two patients showed stable disease. Conclusion  IACI for skull base tumors guided by CBCT navigation is both feasible and safe.

Purpose/Objective(s) Spine stereotactic body radiation therapy (SBRT) outperforms conventional radiotherapy (RT) in local control. Little is known about the incidence of local failure (LF) and vertebral compression fracture (VCF) with spine SBRT in 3 fractions. Materials/Methods This is a retrospective cohort study of 1,502 patients treated to 2,134 lesions between 2014-2023. All patients had no prior overlapping RT and had at least 2 months of MRI follow up. LF was defined as progressive disease on MRI, while VCF was defined as new or progressive fracture on MRI in the absence of LF. LF and VCF rates were compared at the lesion level using Gray's test with death as a competing risk. To generate a dose-response model, we used competing risks regression to predict tumor control probability (TCP) at 2 years as a function of biological effective dose (BED), assuming an α/β of 10. Overall survival (OS) was calculated at the patient level using the Kaplan-Meier method. Results The median follow up after SBRT was 14 months. Median OS was 20 months (95% confidence interval (CI) 18.3-21.6 months). There were 1,201 lesions (56%) that received 27 Gy and 933 (44%) that received 30 Gy. For lesions treated with 30 Gy vs 27 Gy, actuarial incidences of LF at 1, 2, and 3 years were 8% vs 13%, 11% vs 17%, and 13% vs 19%, respectively (p < 0.001). Cholangiocarcinoma (CCa; n=32), colorectal adenocarcinoma (CRC; n=97), and hepatocellular carcinoma (HCC; n=21) lesions had 1-year LF rates of 27%, 22%, and 30%, respectively, while prostate cancer (PCa; n=255) lesions had a 1-year LF rate of 6%. We therefore defined radiosensitive (to SBRT) lesions as PCa, radioresistant lesions as CCa, HCC, or CRCa, and all other histologies as intermediate. On multivariate regression, radioresistant histology was associated with increased risk of LF (HR 2.63, 95% CI 1.89-3.66, p < 0.001); there was a trend for decreased risk of LF with 30 Gy compared to 27 Gy prescription dose, but this trend did not reach statistical significance (HR 0.60, 95% CI 0.35-1.05, p = 0.076). For radiosensitive, intermediate, and radioresistant histologies, our dose-response model predicts that BED10 values of 60, 72, and 77 Gy, respectively, are necessary to achieve 95% TCP 2 years after SBRT. The incidence of any VCF was 4.6% (95% CI 3.7%-5.5%) 2 years after SBRT; the risk was higher for lesions treated to 30 Gy (5.6%) compared with 27 Gy (3.8%); p = 0.022. The cumulative incidence of VCF requiring surgery or kyphoplasty was 2.5% (95% CI 1.8%-3.2%) 2 years after SBRT, and there was no statistically significant difference between 27 Gy (2.0%) compared to 30 Gy (3.1%); p = 0.2. Conclusion With 3-fraction spine SBRT, a prescription dose of 30 Gy provides superior local control compared to 27 Gy, with comparable risk of VCF requiring intervention. Histological radiosensitivity was the most important predictor of LF. For particularly radioresistant histologies such as CRC, CCa, and HCC, our data argue in favor of escalation to a more ablative regimen to maximize local control.

Purpose: The purpose of this study was to evaluate the technical and clinical success of middle meningeal artery (MMA) embolization performed for symptomatic subacute subdural hematoma (SDH) in patients with cancer. Methods: This study retrospectively included 23 consecutive patients (12 men, 11 women; median age 61 years, interquartile range: 55.5-75.5) who underwent 34 MMA angiograms for symptomatic SDH in 2022 and 2023. Median SDH thickness was 10.5 mm (7-12). Median platelet count was 117 K/mcL (54.5-218). 10 patients (43.5%, 10/23) had hematologic malignancies, seven patients (30.4%, 7/ 23) had surgery. Fluoroscopy time (FT), reference dose (RD), and kerma area product (Kap) were analyzed. Adverse events and outcomes were recorded. Results: The median imaging and clinical follow-up were 65 days (36.5-190.5) and 163 days (86-274), respectively. The technical success rate was 91.2% (31/34) as three MMA were not identified in two patients. Median procedure duration was 61 min (55.5-75.5). Median FT was 21.6 min (15.5-31.8); median RD was 158 mGy (96-256); and median Kap was 32.9 Gy.cm2 2 (20.4-45.1). No further intervention was needed. For 16 patients, SDH resolved after in median 59.5 days (50-90). For seven patients, SDH remained visible on the last imaging follow-up performed at 24 days in median (6.5-36.5). No predictive factor of failure was identified. The adverse event rate was 1/23 (4.3%). Eight patients (34.8%, 8/23) died during follow-up from progression of cancer. Conclusion: MMA embolization of symptomatic SDH in patients with cancer appears safe and is associated with improvement in clinical symptoms.