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Background Stereotactic body radiotherapy (SBRT) is increasingly used for patients with oligometastatic prostate cancer, yet the optimal target definition, dose, and toxicity profile for rib metastases remain uncertain. Objectives We assessed local control (LC), toxicity, and the risk of radiation-induced rib fracture (RF) after SBRT for rib metastases. Design Retrospective multicenter cohort study. Methods We analyzed prostate cancer patients with radiologically diagnosed rib metastases treated with SBRT and >=12 months of follow-up. Outcomes were descriptively compared between gross tumor volume (GTV)-only and GTV plus an intraosseous clinical target volume (CTV) margin. Analyses included Kaplan-Meier survival estimates, cumulative incidence functions, and exploratory univariable Cox and logistic regression; no formal equivalence testing or multivariable validation was attempted because event numbers were very low. Results We included 102 patients with a median follow-up of 20 months. The 1- and 2-year LC rates were 97.9% and 96.3%, respectively. At 3 years, local progression was 2.1% in the GTV-only group, absent in patients treated with >=10 mm margins, and numerically highest with 3-5 mm CTV margins (13.5%, p=0.022). Among 13 symptomatic patients, pain control was excellent, with complete or partial response in all patients within 6 months. No grade >=3 toxicities occurred. RFs were rare (n=3, 2.9%), comprising one symptomatic Grade 2 event (0.9%) and two asymptomatic Grade 1 events (2.0%). Baseline symptoms and extraosseous infiltration were associated with RF in exploratory univariable analysis, but confidence intervals were wide. Higher PTV dose exposure, particularly PTV D50% (36.9 vs. 31.1 Gy, p=0.041), was also observed among RF cases. Conclusions SBRT for rib metastases from prostate cancer was associated with high LC, pain relief, and low observed toxicity in this retrospective real-world cohort. GTV-only contouring may be feasible in carefully selected patients staged and planned with PSMA-PET/CT, but the non-randomized design, baseline imbalances, short follow-up, and very low event count preclude drawing conclusions about equivalence or independent validation. RF predictor analyses should be considered exploratory and hypothesis-generating.

PURPOSE Survival for patients with melanoma has recently improved. The propensity of melanoma to metastasize to the brain remains a common and serious feature of this disease. The purposes of this study were to evaluate prognostic factors for patients with newly diagnosed melanoma brain metastases (MBMs) in a large cohort treated with modern multimodal therapies, compare those results with those in prior eras, and update the Melanoma Graded Prognostic Assessment (GPA). METHODS Univariable and multivariable (MVA) analyses of prognostic factors and treatments associated with survival were performed on 1,796 patients with newly diagnosed MBM treated between January 01, 2015, and December 31, 2021, using a multi-institutional retrospective database. Multiple imputation was used to address missingness of potential predictors. Significant variables in combined MVA were used to update the Melanoma GPA. Comparisons were made with legacy cohorts. RESULTS Median survivals for cohorts A (1985-2007, n = 481), B (2006-2015, n = 823), and C (2015-2021, n = 1,796) were 6.7, 9.8, and 16.6 months and median follow-up times were 40.1, 43.6, and 48.8 months, respectively. In combined MVA, significant prognostic factors for survival were higher Karnofsky Performance Status, fewer MBMs, absence of extracranial metastases, lower serum lactate dehydrogenase, and no immunotherapy before MBM. These factors were incorporated into the updated Melanoma GPA. The combined median and 3-year survivals for patients with GPA 0-1, 1.5-2, and 2.5-4.0 were 5.4, 13.2, and 43.2 months and 12.4%, 28.8%, and 51.6%, respectively. CONCLUSION Prognostic factors have changed and survival has improved for patients with MBM but varies widely by GPA. The updated Melanoma GPA calculator (BrainMetGPA), available free online, can be used to estimate survival, individualize treatment, stratify clinical trials, guide surveillance, and augment clinical trial eligibility. Multidisciplinary treatment is essential. Trials are needed to elucidate the optimal sequencing of various therapeutic modalities.

Abstract Background Despite advances in our understanding of the molecular underpinnings of meningioma progression and innovations in systemic and local treatments, recurrent meningiomas remain a substantial therapeutic challenge. The objective of this systematic review and meta-analysis is to provide a historical baseline, contemporary analysis, and propose a “rate of probable interest” to inform future clinical trial design and development on behalf of the Response Assessment in Neuro-Oncology meningioma group. Methods PubMed, ClinicalTrials.gov, and ASCOpubs databases were screened for clinical trials evaluating the activity of systemic therapies for adults with recurrent meningiomas. The pooled progression-free survival at 6-months and 1-year (PFS-6 and PFS-1 year) values were calculated using the random effects technique with I2 indices. Results The pooled PFS-6 and PFS-1 year rates for recurrent WHO grade 1 meningiomas were 43.6% (95% CI: 22.7-67.0%, I2 = 80%) and 21.7% (95% CI: 6.2-53.9%, I2 = 76%), and for grades 2-3 meningiomas, the PFS-6 was 38.0% (95% CI: 28.3-48.8%, I2 = 68%). In the targeted therapy group, PFS-6 and PFS-1 year rates stood at 62.0% (I2 = 58%) and 49.0% (I2 = 63%) for grade 1, while for grades 2-3 tumors, the PFS-6 rates with targeted therapy and immunotherapy were 42.1% (I² = 60%) and 46.0% (I² = 0%), respectively. The benchmarks were set at 67% and 54% for PFS-6 and PFS-1 year for grade 1 tumors, and PFS-6 of 49% for grades 2-3 tumors. Conclusions Several studies have reported outcomes in patients with recurrent meningiomas testing a variety of agents with modest, but variable and progressively increasing activity. In this context, we recommend new benchmarks for future trials to define efficacy of future investigational therapies.

Abstract As cancer patients with intracranial metastatic disease experience increasingly prolonged survival, the diagnosis and management of recurrent brain metastasis pose significant challenges in clinical practice. Prior to deciding upon a management strategy, it is necessary to ascertain whether patients have recurrent/progressive disease vs adverse radiation effect, classify the recurrence as local or distant in the brain, evaluate the extent of intracranial disease (size, number and location of lesions, and brain metastasis velocity), the status of extracranial disease, and enumerate the interval from the last intracranially directed intervention to disease recurrence. A spectrum of salvage local treatment options includes surgery (resection and laser interstitial thermal therapy [LITT]) with or without adjuvant radiotherapy in the forms of external beam radiotherapy, intraoperative radiotherapy, or brachytherapy. Nonoperative salvage local treatments also range from single fraction and fractionated stereotactic radiosurgery (SRS/FSRS) to whole brain radiation therapy (WBRT). Optimal integration of systemic therapies, preferably with central nervous system (CNS) activity, may also require reinterrogation of brain metastasis tissue to identify actionable molecular alterations specific to intracranial progressive disease. Ultimately, the selection of the appropriate management approach necessitates a sophisticated understanding of patient, tumor, and prior treatment-related factors and is often multimodal; hence, interdisciplinary evaluation for such patients is indispensable.

Abstract Background There are limited data on the use of stereotactic radiosurgery (SRS) for pediatric patients. The aim of this systematic review was to summarize indications and outcomes specific to pediatric cranial SRS to inform consensus guidelines on behalf of the International Stereotactic Radiosurgery Society. Methods A systematic review, using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses, analyzed English-language articles on SRS, published between 1989 and 2021, that included outcomes for at least 5 pediatric patients. MEDLINE database terms included tumor types and locations, and radiosurgical and age-specific terms. We excluded nonclinical reports, expert opinions, commentaries, and review articles. Meta-regressions for associations with local control were performed for medulloblastoma, craniopharyngioma, ependymoma, glioma, and arteriovenous malformation (AVM). Results Of the 113 articles identified for review, 68 met the inclusion criteria. These articles described approximately 400 pediatric patients with benign and malignant brain tumors and 5119 with AVMs who underwent cranial SRS. The rates of local control for benign tumors, malignant tumors, and AVMs were 89% (95% CI, 82%–95%), 71% (95% CI, 59%–82%), and 65% (95% CI, 60%–69%), respectively. No significant associations were identified for local control with the patient-, tumor-, or treatment-related variables. Conclusions This review is the first to summarize outcomes specific to SRS for pediatric brain tumors and AVMs. Although data reporting is limited for pediatric patients, SRS appears to provide acceptable rates of local control. We present ISRS consensus guidelines to inform the judicious use of cranial SRS for pediatric patients.

BACKGROUND AND OBJECTIVES: Consensus guidelines do not exist to guide the role of stereotactic radiosurgery (SRS) in the management of patients with Spetzler-Martin Grade III-V arteriovenous malformations (AVMs). We sought to establish SRS practice guidelines for Grade III-V AVMs based on a critical systematic review of the published literature. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant search of Medline, Embase, and Scopus, 1986 to 2023, for publications reporting post-SRS outcomes in ≥10 Grade III-V AVMs with the median follow-up ≥24 months was performed. Primary end points were AVM obliteration and post-SRS hemorrhage. Secondary end points included dosimetric variables, Spetzler-Martin parameters, and neurological outcome. RESULTS : In total, 2463 abstracts were screened, 196 manuscripts were reviewed, and 9 met the strict inclusion criteria. The overall sample of 1634 AVMs consisted of 1431 Grade III (88%), 186 Grade IV (11%), and 11 Grade V lesions (1%). Total median post-SRS follow-up was 53 months for Grade III and 43 months for Grade IV-V AVMs (ranges, 2-290; 12-262). For Grade III AVMs, the crude obliteration rate was 72%, and among Grade IV-V lesions, the crude obliteration rate was 46%. Post-SRS hemorrhage was observed in 7% of Grade III compared with 17% of Grade IV-V lesions. Major permanent deficits or death from hemorrhage or radiation-induced complications occurred in 86 Grade III (6%) and 22 Grade IV-V AVMs (12%). CONCLUSION: Most patients with Spetzler-Martin Grade III AVMs have favorable SRS treatment outcomes; however, the obliteration rate for Grade IV-V AVMs is less than 50%. The available studies are heterogenous and lack nuanced, long-term, grade-specific outcomes.

BACKGROUND AND OBJECTIVES: Repeat stereotactic radiosurgery (SRS) for residual arteriovenous malformations (AVMs) can be considered as a salvage approach after failure of initial SRS. There are no published guidelines regarding patient selection, timing, or SRS parameters to guide clinical practice. This systematic review aimed to review outcomes and complications from the published literature to inform practice recommendations provided on behalf of the International Stereotactic Radiosurgery Society. METHODS: We performed a systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of MEDLINE, Scopus, Web of Science, and Embase was conducted. Fourteen studies with 925 patients met the inclusion criteria. Patients were treated between 1985 and 2022. All studies were retrospective, except for one prospective cohort. RESULTS: The median patient age at repeat SRS ranged from 32 to 60 years. Four studies (630 patients) reported detailed information on Spetzler–Martin grade at the time of repeat SRS; 12.54% of patients had Spetzler–Martin grade I AVMs (79/630 patients), 46.51% had grade II (293/630), 34.92% had grade III (220/630), 5.08% had grade IV (32/630), and 0.95% had grade V (6/630). The median prescription doses varied between 15 and 25 Gy (mean, 13.06-22.8 Gy). The pooled overall obliteration rate at the last follow-up after repeat SRS was 59% (95% CI 51%-67%) with a median follow-up between 21 and 50 months. The pooled hemorrhage incidence at the last follow-up was 5% (95% CI 4%-7%), and the pooled overall radiation-induced change incidence was 12% (95% CI 7%-20%). CONCLUSION: For an incompletely obliterated AVM, repeat radiosurgery after 3 to 5 years of follow-up from the first SRS provides a reasonable benefit to the risk profile. After repeat SRS, obliteration is achieved in the majority of patients. The risk of hemorrhage or radiation-induced change appears low, and International Stereotactic Radiosurgery Society recommendations are presented.

Mutations in isocitrate dehydrogenase (IDH) genes, an early step in the ontogeny of lower-grade gliomas, induce global epigenetic changes characterized by a hypermethylation phenotype and are critical to tumor classification, treatment decision making, and estimation of patient prognosis. The introduction of IDH inhibitors to block the oncogenic neomorphic function of the mutated protein has resulted in new therapeutic options for these patients. To appreciate the implications of these recent IDH inhibitor results, it is important to juxtapose historical outcomes with chemoradiotherapy. Herein, we rationally evaluate recent IDH inhibitor data within historical precedents to guide contemporary decisions regarding the role of observation, maximal safe resection, adjuvant therapies, and the import of patient and tumor variables. The biological underpinnings of the IDH pathway and the mechanisms, impact, and limitations of IDH inhibitors, the actual magnitude of tumor regression and patient benefit, and emergence of resistance pathways are presented to guide future trial development. Management in the current, molecularly defined era will require careful patient selection and risk factor assessment, followed by an open dialog about the results of studies such as INDIGO, as well as mature data from legacy trials, and a discussion about risk-versus-benefit for the choice of treatment, with multidisciplinary decision making as an absolute prerequisite.

Abstract Background The choice of an appropriate strategy for intracanalicular vestibular schwannoma (ICVS) is still debated. We conducted a systematic review and meta-analysis with the aim to compare treatment outcomes amongst management strategies (conservative surveillance (CS), microsurgical resection (MR), or stereotactic radiosurgery (SRS)) aiming to inform guideline recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS). Methods Using PRISMA guidelines, we reviewed manuscripts published between January 1990 and October 2021 referenced in PubMed or Embase. Inclusion criteria were peer-reviewed clinical studies or case series reporting a cohort of ICVS managed with CS, MR, or SRS. Primary outcome measures included tumor control, the need for additional treatment, hearing outcomes, and posttreatment neurological deficits. These were pooled using meta-analytical techniques and compared using meta-regression with random effect. Results Forty studies were included (2371 patients). The weighted pooled estimates for tumor control were 96% and 65% in SRS and CS series, respectively (P < .001). Need for further treatment was reported in 1%, 2%, and 25% for SRS, MR, and CS, respectively (P = .001). Hearing preservation was reported in 67%, 68%, and 55% for SRS, MR, and CS, respectively (P = .21). Persistent facial nerve deficit was reported in 0.1% and 10% for SRS and MR series, respectively (P = .01). Conclusions SRS is a noninvasive treatment with at least equivalent rates of tumor control and hearing preservation as compared to MR, with the caveat of better facial nerve preservation. As compared to CS, upfront SRS is an effective treatment in achieving tumor control with similar rates of hearing preservation.

Abstract BACKGROUND Differentiating radiation necrosis from tumour progression after radiation therapy (RT) for brain metastases (BM) remains clinically challenging, and accurate imaging is crucial to prevent unnecessary surgery or unwarranted changes in therapy. 18F-Fluciclovine is a PET radiopharmaceutical with low background uptake in the brain and increased uptake in BM. The PURSUE study (NCT04410367) aimed to establish image interpretation criteria (IIC) for detecting suspected recurrent BM after RT using 18F-fluciclovine PET, based on several measures of lesion uptake. MATERIAL AND METHODS Across 7 US sites, 23 patients with solid tumour BM and a previously irradiated ‘reference’ lesion equivocal for recurrence on MRI who were scheduled for craniotomy underwent 18F-fluciclovine PET (185 MBq) <42 days post-MRI and 1-21 days pre-craniotomy. Three independent, blinded readers qualitatively rated lesion 18F-fluciclovine uptake as ‘mild’ (up to blood pool), ‘moderate’ (above blood pool to parotid gland), or ‘marked’ (above parotid gland). The primary endpoint was the diagnostic performance of different thresholds of lesion uptake on qualitative (visual) reads vs central histopathology. Secondary endpoints included diagnostic performance, based on different thresholds, of quantitative (e.g., lesion standardized uptake value [SUV]), and dynamic measures. A committee, including two independent imaging physicians, reviewed all data to establish the IIC, which were subsequently used to evaluate the diagnostic performance of 18F-fluciclovine. RESULTS All 23 reference lesions underwent histopathological analysis, with 10 (43%) being pathologically confirmed BM recurrence. The highest performing qualitative measure of 18F-fluciclovine lesion uptake was ‘marked’, rendering 92-100% and variable (40-80%) across readers. SUVmax was a reader-independent, high-performing quantitative metric (AUC 0.87, SUVmax threshold 4.8, 80% sensitivity, 85% specificity). Dynamic measures did not add diagnostic value. Thus, the committee established IIC as: "Lesions with 18F-fluciclovine uptake of a SUVmax equal to or greater than 4.8, or visually greater than the parotid gland, should be considered suspicious for recurrence. Otherwise, recurrence should be considered unlikely." Application of these IIC resulted in 80% sensitivity, 77-85% specificity, 73-80% positive predictive value, and 83-85% negative predictive value across readers. CONCLUSION PURSUE is the first prospective, multicentre study to define IIC for 18F-fluciclovine PET for accurate identification of suspected recurrent BM after RT, verified by histopathology. In this initial cohort, the IIC convey excellent diagnostic performance for 18F-fluciclovine and will help evaluate 18F-fluciclovine PET in future studies. This study was sponsored by Blue Earth Diagnostics Ltd.