Molecular mechanisms controlling vertebrate retinal patterning, neurogenesis, and cell fate specification.

This review covers recent advances in understanding the molecular mechanisms controlling neurogenesis and specification of the developing retina, with a focus on insights obtained from comparative single cell multiomic analysis. We discuss recent advances in understanding the mechanisms by which extrinsic factors trigger transcriptional changes that spatially pattern the optic cup (OC) and control the initiation and progression of retinal neurogenesis. We also discuss progress in unraveling the core evolutionarily conserved gene regulatory networks (GRNs) that specify early- and late-state retinal progenitor cells (RPCs) and neurogenic progenitors and that control the final steps in determining cell identity. Finally, we discuss findings that provide insight into regulation of species-specific aspects of retinal patterning and neurogenesis, including consideration of key outstanding questions in the field.

Comparative evaluation of outcomes amongst different radiosurgery management paradigms for patients with large brain metastasis.

INTRODUCTION: This study compares four management paradigms for large brain metastasis (LMB): fractionated SRS (FSRS), staged SRS (SSRS), resection and postoperative-FSRS (postop-FSRS) or preoperative-SRS (preop-SRS). METHODS: Patients with LBM (≥ 2 cm) between July 2017 and January 2022 at a single tertiary institution were evaluated. Primary endpoints were local failure (LF), radiation necrosis (RN), leptomeningeal disease (LMD), a composite of these variables, and distant intracranial failure (DIF). Gray's test compared cumulative incidence, treating death as a competing risk with a random survival forests (RSF) machine-learning model also used to evaluate the data. RESULTS: 183 patients were treated to 234 LBMs: 31.6% for postop-FSRS, 28.2% for SSRS, 20.1% for FSRS, and 20.1% for preop-SRS. The overall 1-year composite endpoint rates were comparable (21 vs 20%) between nonoperative and operative strategies, but 1-year RN rate was 8 vs 4% (p = 0.012), 1-year overall survival (OS) was 48 vs. 69% (p = 0.001), and 1-year LMD rate was 5 vs 10% (p = 0.052). There were differences in the 1-year RN rates (7% FSRS, 3% postop-FSRS, 5% preop-SRS, 10% SSRS, p = 0.037). With RSF analysis, the out-of-bag error rate for the composite endpoint was 47%, with identified top-risk factors including widespread extracranial disease, > 5 total lesions, and breast cancer histology. CONCLUSION: This is the first study to conduct a head-to-head retrospective comparison of four SRS methods, addressing the lack of randomized data in LBM literature amongst treatment paradigms. Despite patient characteristic trends, no significant differences were found in LF, composite endpoint, and DIF rates between non-operative and operative approaches.

Comparative evaluation of the diagnostic and prognostic performance of CNSide™ versus standard cytology for leptomeningeal disease.

Background: This retrospective study compares the real-world performance of cerebrospinal fluid (CSF) CNSide™ versus cytology in leptomeningeal disease (LMD). Methods: Consecutive patients with suspected LMD who underwent lumbar punctures for CSF cytology and CNSide™ from January 2020 to December 2022 were reviewed. LMD was classified by EANO criteria. Descriptive statistics, confusion matrix, Kaplan-Meier curves, and Cox proportional regression were used. Results: Median age for 87 evaluable patients was 63 years (range: 23-93); 82 (94%) met EANO criteria for possible/probable/confirmed LMD (EANO/LMD). The commonest primary cancers were breast (36,44.0%) and lung (34,41.5%). Primary lung harbored actionable mutations in 18 (53.0%); primary breast expressed hormone receptors in 27 (75%), and HER2 amplification in 8 (22%). Uncontrolled systemic disease was detected in 35 (40%), while 25 (46%) received systemic therapy with medium/high CNS penetrance at LMD diagnosis. The median time from initial cancer to LMD diagnosis was 31 months (range: 13-73). LMD was confirmed by CSF cytology in 23/82 (28%), all identified by CNSide™. CNSide™ identified 13 additional cases (36/82, 43.9%), increasing diagnostic yield by 56.5%. Median overall survival (mOS) was 31 weeks (95%CI: 21-43), significantly worse for CNSide™ positive versus negative: 4.0 versus 16.0 weeks, respectively (HR = 0.50, P = .010). While survival since LMD diagnosis did not differ by histology, time to LMD diagnosis from initial cancer diagnosis was longer for breast (48.5 months, IQR: 30.0-87.5) versus lung (8 months, IQR:0.5-16.0) cohorts. mOS was longer for patients eligible for intrathecal chemotherapy (HR: 0.189, 95%CI: 0.053-0.672, P = .010). Conclusions: This retrospective, real-world analysis of CNSide™ showed increased sensitivity versus cytology and provided clinically relevant molecular CSF analyses.

Prophylactic Radiotherapy Of MInimally Symptomatic Spinal Disease (PROMISSeD): study protocol for a randomized controlled trial.

BACKGROUND: Early palliative/pre-emptive intervention improves clinical outcomes and quality of life for patients with metastatic cancer. A previous signal-seeking randomized controlled trial (RCT) demonstrated that early upfront radiotherapy to asymptomatic or minimally symptomatic high-risk osseous metastases led to reduction in skeletal-related events (SREs), a benefit driven primarily by subgroup of high-risk spine metastasis. The current RCT aims to determine whether early palliative/pre-emptive radiotherapy in patients with high-risk, asymptomatic or minimally symptomatic spine metastases will lead to fewer SREs within 1 year. METHODS: This is a single-center, parallel-arm, in-progress RCT in adults (≥ 18 years) with ECOG performance status 0-2 and asymptomatic or minimally symptomatic (not requiring opioids) high-risk spine metastases from histologically confirmed solid tumor malignancies with > 5 sites of metastatic disease on cross-sectional imaging. High-risk spine metastases are defined by the following: (a) bulkiest disease sites ≥ 2 cm; (b) junctional disease (occiput to C2, C7-T1, T12-L2, L5-S1); (c) posterior element involvement; or (d) vertebral body compression deformity > 50%. Patients are randomized 1:1 to receive either standard-of-care systemic therapy (arm 1) or upfront, early radiotherapy to ≤ 5 high-risk spine lesions plus standard-of-care systemic therapy (arm 2), in the form of 20-30 Gy of radiation in 2-10 fractions. The primary endpoint is SRE, a composite outcome including spinal fracture, spinal cord compression, need for palliative radiotherapy, interventional procedures, or spinal surgery. Secondary endpoints include (1) surrogates of health care cost, including the number and duration of SRE-related hospitalizations; (2) overall survival; (3) pain-free survival; and (4) quality of life. Study instruments will be captured pre-treatment, at baseline, during treatment, and at 1, 3, 6, 12, and 24 months post-treatment. The trial aims to accrue 74 patients over 2 years to achieve > 80% power in detecting difference using two-sample proportion test with alpha < 0.05. DISCUSSION: The results of this RCT will demonstrate the value, if any, of early radiotherapy for high-risk spine metastases. The trial has received IRB approval, funding, and prospective registration (NCT05534321) and has been open to accrual since August 19, 2022. If positive, the trial will expand the scope and utility of spine radiotherapy. TRIAL REGISTRATION: ClinicalTrials.Gov NCT05534321 . Registered September 9, 2022. TRIAL STATUS: Version 2.0 of the protocol (2021-KOT-002), revised last on September 2, 2022, was approved by the WCG institutional review board (Study Number 1337188, IRB tracking number 20223735). The trial was first posted on ClinicalTrials.Gov on September 9, 2022 (NCT05534321). Patient enrollment commenced on August 19, 2022, and is expected to be completed in 2 years, likely by August 2024.

Racial disparities in clinical presentation, surgical procedures, and hospital outcomes among patients with hepatocellular carcinoma in the United States.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths in the United States (US), with substantial disparities observed in cancer incidence and survival among racial groups. This study provides analyses on race and ethnicity disparities for patients with HCC. METHODS: This is a cross-sectional analysis of data from the National Inpatient Sample (NIS) between 2011 and 2016, utilizing the STROBE guidelines. Multivariate logistic regression analyses were used to examine the risk-adjusted associations between race and pre-treatment clinical presentation, surgical procedure allocation, and post-treatment hospital outcomes. All clinical parameters were identified using ICD-9-CM and ICD-10-CM diagnosis and procedure codes. RESULTS: 83,876 weighted HCC hospitalizations were reported during the study period. Patient demographics were divided according to NIS racial/ethnic categorization, which includes Caucasian (57.3%), African American (16.9%), Hispanic (15.7%), Asian or Pacific Islanders (9.3%), and Native American (0.8%). Association between greater odds of hospitalization and Elixhauser Comorbidity Index > 4 was significantly higher among Native Americans (aOR=1.79; 95% CI: 1.23-2.73), African Americans (aOR=1.24; 95% CI: 1.12-1.38), and Hispanics (aOR=1.11; 95% CI, 1.01-1.24). Risk-adjusted association between race and receipt of surgical procedures demonstrated that the odds of having surgery was significantly lower for African Americans (aOR=0.64; 95% CI: 0.55-0.73) and Hispanics (aOR=0.70; 95% CI: 0.59-0.82), while significantly higher for Asians/Pacific Islanders (aOR=1.36; 95% CI: 1.28-1.63). Post-operative complications were significantly lower for African Americans (aOR=0.68; 95% CI: 0.55-0.86) while the odds of in-hospital mortality were significantly higher for African Americans (aOR=1.28; 95% CI: 1.11-1.49) and Asians/Pacific Islanders (aOR=1.26; 95% CI: 1.13-1.62). CONCLUSIONS: After controlling for potential confounders, there were significant racial disparities in pre-treatment presentations, surgical procedure allocations, and post-treatment outcomes among patients with HCC. Further studies are needed to determine the underlying factors for these disparities to develop targeted interventions to reduce these disparities of care.

Surgically targeted radiation therapy (STaRT) for recurrent brain metastases: Initial clinical experience.

PURPOSE: This study evaluates the outcomes of recurrent brain metastasis treated with resection and brachytherapy using a novel Cesium-131 carrier, termed surgically targeted radiation therapy (STaRT), and compares them to the first course of external beam radiotherapy (EBRT). METHODS: Consecutive patients who underwent STaRT between August 2020 and June 2022 were included. All patients underwent maximal safe resection with pathologic confirmation of viable disease prior to STaRT to 60 Gy to a 5-mm depth from the surface of the resection cavity. Complications were assessed using CTCAE version 5.0. RESULTS: Ten patients with 12 recurrent brain metastases after EBRT (median 15.5 months, range: 4.9-44.7) met the inclusion criteria. The median BED10Gy90% and 95% were 132.2 Gy (113.9-265.1 Gy) and 116.0 Gy (96.8-250.6 Gy), respectively. The median maximum point dose BED10Gy for the target was 1076.0 Gy (range: 120.7-1478.3 Gy). The 6-month and 1-year local control rates were 66.7% and 33.3% for the prior EBRT course; these rates were 100% and 100% for STaRT, respectively (p < 0.001). At a median follow-up of 14.5 months, there was one instance of grade two radiation necrosis. Surgery-attributed complications were observed in two patients including pseudomeningocele and minor headache. CONCLUSIONS: STaRT with Cs-131 presents an alternative approach for operable recurrent brain metastases and was associated with superior local control than the first course of EBRT in this series. Our initial clinical experience shows that STaRT is associated with a high local control rate, modest surgical complication rate, and low radiation necrosis risk in the reirradiation setting.

Ectopic insert-dependent neuronal expression of GFAP promoter-driven AAV constructs in adult mouse retina.

Direct reprogramming of retinal Müller glia is a promising avenue for replacing photoreceptors and retinal ganglion cells lost to retinal dystrophies. However, questions have recently been raised about the accuracy of studies claiming efficient glia-to-neuron reprogramming in retina that were conducted using GFAP mini promoter-driven adeno-associated virus (AAV) vectors. In this study, we have addressed these questions using GFAP mini promoter-driven AAV constructs to simultaneously overexpress the mCherry reporter and candidate transcription factors predicted to induce glia-to-neuron conversion, in combination with prospective genetic labeling of retinal Müller glia using inducible Cre-dependent GFP reporters. We find that, while control GFAP-mCherry constructs express faithfully in Müller glia, 5 out of 7 transcription factor overexpression constructs tested are predominantly expressed in amacrine and retinal ganglion cells. These findings demonstrate strong insert-dependent effects on AAV-based GFAP mini promoter specificity that preclude its use in inferring cell lineage relationships when studying glia-to-neuron conversion in retina.

Feasibility of Tumor Treating Fields with Pemetrexed and Platinum-Based Chemotherapy for Unresectable Malignant Pleural Mesothelioma: Single-Center, Real-World Data.

PURPOSE: The objectives of this study were to evaluate the implementation, device usage rates, clinical outcomes, and treatment-related toxicities associated with TTFields and pemetrexed plus platinum-based chemotherapy in patients with unresectable MPM, outside the initial trial results. METHODS: Consecutive patients with unresectable MPM were enrolled onto an FDA-required HDE protocol from 2019 to 2021. All patients were treated with a protocol-defined regimen of continuous TTFields (150 kHz) and pemetrexed plus platinum-based chemotherapy. RESULTS: Five patients with unresectable MPM were enrolled. The median number of 4-week TTFields cycles was 5 (range: 2-7 cycles). Median TTFields device usage in the first 3 months was 12.5 h per day (range: 5-16.8 h), representing 52% (21-70%) of the potential daily duration. The median follow-up was 5.4 months (range: 1.1-20.9 months). Treatment-related dermatitis was the only side effect associated with TTFields and was reported as grade 1-2 in all patients; no patient had grade 3+ device-related toxicities. CONCLUSIONS: This study represents the first results of real-world implementation of TTFields for MPM. In comparison to the initial clinical trial (STELLAR), compliance rates were lower, although skin-related toxicities appeared similar. Further initiatives and guidelines should be developed to manage treatment-related dermatitis and improve device usage.

Genetic loss of function of Ptbp1 does not induce glia-to-neuron conversion in retina.

Direct reprogramming of glia into neurons is a potentially promising approach for the replacement of neurons lost to injury or neurodegenerative disorders. Knockdown of the polypyrimidine tract-binding protein Ptbp1 has been recently reported to induce efficient conversion of retinal Mϋller glia into functional neurons. Here, we use a combination of genetic lineage tracing, single-cell RNA sequencing (scRNA-seq), and electroretinogram analysis to show that selective induction of either heterozygous or homozygous loss-of-function mutants of Ptbp1 in adult retinal Mϋller glia does not lead to any detectable level of neuronal conversion. Only a few changes in gene expression are observed in Mϋller glia following Ptbp1 deletion, and glial identity is maintained. These findings highlight the importance of using genetic manipulation and lineage-tracing methods in studying cell-type conversion.

Evaluation of a prospective radiation oncology departmental team review process using standardized simulation directives.

INTRODUCTION: The primary objective of this study is to evaluate the utility and value of an institutional, multi-disciplinary radiation oncology team review process prior to radiotherapy (RT) simulation. METHODS: Over a period of 3 months and through an iterative team-based process, a standardized simulation requisition directive (SSRD) was developed, piloted, modified, and subsequently implemented for all patients treated with external beam RT at a single tertiary care institution from January to December 2020. The SSRDs were reviewed at a daily multi-disciplinary radiation oncology team review conference; modifications consequential to the review were prospectively recorded in a quality database. RESULTS: 1500 consecutive SSRDs were prospectively reviewed for this study. 397 modifications on 290 (19.3%) SSRDs were recorded and parsed into 5 main categories and 18 subcategories. The most common modifications resulted from changes in immobilization device (n = 88, 22.2%), RT care path (n = 56, 14.1%), and arm positioning (n = 43, 10.8%). On univariate analysis, modifications were associated with RT intent, scan parameters, tumor site, and consultation type. An increased rate modifications was observed for patients had telemedicine consults (n = 101, 22.7%) compared to in-person consultations (n = 189, 17.9%) (p = 0.032). Using logistic regression analysis, there was also a statistically significant relationship between postoperative RT delivery and modification rates (OR: 2.913, 95% CI: 1.014-8.372) (p = 0.0126). Overall, only 14 patients (0.9%) needed re-simulation during the entire study period. CONCLUSIONS: Prospective multi-disciplinary radiation oncology team review prior to simulation identifies actionable change in approximately 19% of procedures, and results in an extremely low rate (<1%) of re-simulation. As departmental processes transition to virtual platforms, thorough attention is needed to identify patients at higher risk of simulation modifications.

Pulsed-Reduced Dose Rate (PRDR) Radiotherapy for Recurrent Primary Central Nervous System Malignancies: Dosimetric and Clinical Results.

PURPOSE: The objective was to describe PRDR outcomes and report EQD2 OAR toxicity thresholds. METHODS: Eighteen patients with recurrent primary CNS tumors treated with PRDR at a single institution between April 2017 and September 2021 were evaluated. The radiotherapy details, cumulative OAR doses, progression-free survival (PFS), overall survival (OS), and toxicities were collected. RESULTS: The median PRDR dose was 45 Gy (range: 36-59.4 Gy); the median cumulative EQD2 prescription dose was 102.7 Gy (range: 93.8-120.4 Gy). The median cumulative EQD2 D0.03cc for the brain was 111.4 Gy (range: 82.4-175.2 Gy). Symptomatic radiation necrosis occurred in three patients, for which the median EQD2 brain D0.03cc was 115.9 Gy (110.4-156.7 Gy). The median PFS and OS after PRDR were 6.3 months (95%CI: 0.9-11.6 months) and 8.6 months (95%CI: 4.9-12.3 months), respectively. The systematic review identified five peer-reviewed studies with a median cumulative EQD2 prescription dose of 110.3 Gy. At a median follow-up of 8.7 months, the median PFS and OS were 5.7 months (95%CI: 2.1-15.4 months) and 6.7 months (95%CI: 3.2-14.2 months), respectively. CONCLUSION: PRDR re-irradiation is a relatively safe and feasible treatment for recurrent primary CNS tumors. Despite high cumulative dose to OARs, the risk of high-grade, treatment-related toxicity within the first year of follow-up remains acceptable.

Zero Setup Margin Mask versus Frame Immobilization during Gamma Knife® Icon™ Stereotactic Radiosurgery for Brain Metastases.

We compared the clinical outcomes of BM treated with mask immobilization with zero-SM (i.e., zero-PTV) to standard zero-SM frame immobilization SRS. Consecutive patients with BM, 0.5−2.0 cm in maximal diameter, treated with single-fraction SRS (22−24 Gy) during March 2019−February 2021 were included. Univariable and multivariable analysis were performed using the Kaplan−Meier method and Cox proportional hazards regression. A total of 150 patients with 453 BM met inclusion criteria. A total of 129 (28.5%) lesions were treated with a zero-SM mask immobilization and 324 (71.5%) with zero-SM frame immobilization. Frame immobilization treatments were associated with a higher proportion of gastrointestinal and fewer breast-cancer metastases (p = 0.024), and a higher number of treated lesions per SRS course (median 7 vs. 3; p < 0.001). With a median follow up of 15 months, there was no difference in FFLF between the mask and frame immobilization groups on univariable (p = 0.29) or multivariable analysis (p = 0.518). Actuarial FFLF at 1 year was 90.5% for mask and 92% for frame immobilization (p = 0.272). Radiation necrosis rates at 1 year were 12.5% for mask and 4.1% for frame immobilization (p = 0.502). For BM 0.5−2.0 cm in maximal diameter treated with single-fraction SRS using 22−24 Gy, mask immobilization with zero SM produces comparable clinical outcomes to frame immobilization. The initial findings support omitting a SM when using mask immobilization with this treatment approach on a Gamma Knife® Icon™.

Dedicated isotropic 3-D T1 SPACE sequence imaging for radiosurgery planning improves brain metastases detection and reduces the risk of intracranial relapse.

BACKGROUND: Stereotactic radiosurgery (SRS) is increasingly used for brain metastases (BM) patients, but distant intracranial failure (DIF) remains the principal disadvantage of this focal therapeutic approach. The objective of this study was to determine if dedicated SRS imaging would improve lesion detection and reduce DIF. METHODS: Between 02/2020 and 01/2021, SRS patients at a tertiary care institution underwent dedicated treatment planning MRIs of the brain including MPRAGE and SPACE post-contrast sequences. DIF was calculated using the Kaplan-Meier method; comparisons were made to a historical consecutive cohort treated using MPRAGE alone (02/2019-01/2020). RESULTS: 134 patients underwent 171 SRS courses for 821 BM imaged with both MPRAGE and SPACE (primary cohort). MPRAGE sequence evaluation alone detected 679 lesions. With neuroradiologists evaluating SPACE and MPRAGE, an additional 108 lesions were identified (p < 0.001). Upon multidisciplinary review, 34 additional lesions were identified. Compared to the historical cohort (103 patients, 135 SRS courses, 479 BM), the primary cohort had improved median time to DIF (13.5 vs. 5.1 months, p = 0.004). The benefit was even more pronounced for patients treated for their first SRS course (18.4 vs. 6.3 months, p = 0.001). SRS using MPRAGE and SPACE was associated with a 60% reduction in risk of DIF compared to the historical cohort (HR: 0.40; 95% CI: 0.28-0.57, p < 0.001). CONCLUSIONS: Among BM patients treated with SRS, a treatment planning SPACE sequence in addition to MPRAGE substantially improved lesion detection and was associated with a statistically significant and clinically meaningful prolongation in time to DIF, especially for patients undergoing their first SRS course.

Meta-Analysis of Survival and Development of a Prognostic Nomogram for Malignant Pleural Mesothelioma Treated with Systemic Chemotherapy.

(1) Purpose: Malignant pleural mesothelioma (MPM) is a rare cancer with an aggressive course. For patients who are medically inoperable or surgically unresectable, multi-agent systemic chemotherapy remains an accepted standard-of-care. The purpose of this meta-analysis is to provide baseline summative survival estimates as well as evaluate the influence of prognostic variables to provide comparative estimates for future trial designs. (2) Methods: Using PRISMA guidelines, a systematic review and meta-analysis was performed of MPM studies published from 2002-2019 obtained from the Medline database evaluating systemic therapy combinations for locally advanced or metastatic disease. Weighted random effects models were used to calculate survival estimates. The influence of proportions of known prognostic factors on overall survival (OS) were evaluated in the creation of a prognostic nomogram to estimate survival. The performance of this model was evaluated against data generated from one positive phase II study and two positive randomized trials. (3) Results: Twenty-four phase II studies and five phase III trials met the eligibility criteria; 2534 patients were treated on the included clinical studies. Ten trials included a platinum-pemetrexed-based treatment regimen, resulting in a pooled estimate of progression-free survival (PFS) of 6.7 months (95% CI: 6.2-7.2 months) and OS of 14.2 months (95% CI: 12.7-15.9 months). Fifteen experimental chemotherapy regimens have been tested in phase II or III studies, with a pooled median survival estimate of 13.5 months (95% CI: 12.6-14.6 months). Meta-regression analysis was used to estimate OS with platinum-pemetrexed using a variety of features, such as pathology (biphasic vs. epithelioid), disease extent (locally advanced vs. metastatic), ECOG performance status, age, and gender. The nomogram-predicted estimates and corresponding 95% CIs performed well when applied to recent randomized studies. (4) Conclusions: Given the rarity of MPM and the aggressive nature of the disease, innovative clinical trial designs with significantly greater randomization to experimental regimens can be performed using robust survival estimates from prior studies. This study provides baseline comparative values and also allows for accounting for differing proportions of known prognostic variables.

Systematic review and meta-analysis of breast cancer brain metastasis and primary tumor receptor expression discordance.

BACKGROUND: Change in hormone receptor (estrogen [ER] and progesterone [PR]) and/or human epidermal growth factor receptor type 2 (HER2) status during the evolutionary course of metastatic breast cancer and the effect of tumor classification subtype switching remain understudied and underappreciated in brain metastasis patients. METHODS: Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a systematic review of series published prior to April 2020 obtained from the Medline database of biopsied or resected breast cancer brain metastasis (BCBM) was performed. Weighted random effects models were used to calculate pooled estimates. RESULTS: 15 full-text articles were included with receptor expression analyses on 1373 patients who underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. Primary tumor receptor expression immunophenotypes were 45.0% ER+, 41.0% ER-, 31.0% PR+, 51.0% PR-, 35% HER2+, and 47.0% HER2-. Corresponding BCBM immunophenotypes were 19.0% ER+, 31.0% ER-, 13.0% PR+, 40.0% PR-, 21.0% HER2+, and 26.0% HER2-. On primary/BCBM comparison, 540 patients (42.6%) exhibited discordance in any receptor with 17.0% (95% CI: 13.0%-23.0%) discordant on ER, 23.0% (95% CI: 18.0%-30.0%) discordant on PR, and 12.0% (95% CI: 8.0%-16.0%) discordant on HER2 status. The most common receptor conversions found in BCBM were ER loss 11.0% (95% CI: 8.0%-16.0%), PR loss 15.0% (95% CI: 11.0%-21.0%), and HER2 gain 9.0% (95% CI: 7.0%-11.0%). CONCLUSIONS: BCBM exhibits significant receptor expression discordance in comparison to primary tumors in approximately 40% of patients. Classification patterns need to be analyzed to determine factors predictive of BCBM/primary tumor discordance. Overall, tumor subtype switching and its effect on clinical management remains underappreciated.

Regression of Intracranial Meningiomas Following Treatment with Cabozantinib.

Recurrent meningiomas remain a substantial treatment challenge given the lack of effective therapeutic options aside from surgery and radiation therapy, which yield limited results in the retreatment situation. Systemic therapies have little effect, and responses are rare; the search for effective systemic therapeutics remains elusive. In this case report, we provide data regarding significant responses in two radiographically diagnosed intracranial meningiomas in a patient with concurrent thyroid carcinoma treated with cabozantinib, an oral multitarget tyrosine kinase inhibitor with potent activity against MET and VEGF receptor 2. Given the clinical experience supporting the role of VEGF agents as experimental therapeutics in meningioma and the current understanding of the biological pathways underlying meningioma growth, this may represent a new oral therapeutic alternative, warranting prospective evaluation.

Systematic review and meta-analysis of lung cancer brain metastasis and primary tumor receptor expression discordance.

BACKGROUND: Treatment paradigms for metastatic non-small cell lung cancer are increasingly based on biomarker-driven therapies, with the most common alteration being mutation in the epidermal growth factor receptor (EGFR). Change in expression of such biomarkers could have a profound impact on the choice and efficacy of a selected targeted therapeutic, and hence the objective of this study was to analyze discordance in EGFR status in patients with lung cancer brain metastasis (LCBM). METHODS: Using PRISMA guidelines, a systematic review was performed of series in the Medline database of biopsied or resected LCBM published before May, 2020. Key words included "lung cancer" and "brain metastasis" combined with "epidermal growth factor receptor/EGFR," and "receptor conversion/discordance or concordance." Weighted random effects models were used to calculate pooled estimates. RESULTS: We identified 501 patients from 19 full-text articles for inclusion in this study. All patients underwent biopsy or resection of at least one intracranial lesion to compare to the primary tumor. On primary/LCBM comparison, the weighted pooled estimate for overall EGFR receptor discordance was 10% (95% CI 5-17%). The weighted effects model estimated a gain of an EGFR mutation in a brain metastases in patients with negative primary tumors was 7% (95% CI 4-12%). Alternatively, the weighted effects model estimate of loss of an EGFR mutation in patients with detected mutations in the primary tumor was also 7% (95% CI 4-10%). KRAS testing was also performed on both primary tumors and LCBM in a subset of 148 patients. The weighted effects estimate of KRAS-mutation discordance among LCBM compared to primary tumors was 13% (95% CI 5-27%). The weighted effects estimated of KRAS gain and loss in LCBM was 10% (95% CI 6-18%) and 8% (95% CI 4-15%), respectively. Meta-regression analysis did not find any association with any factors that could be associated with discordances. CONCLUSIONS: EGFR and KRAS mutation status discordance between primary tumor and LCBM occurs in approximately 10% and 13% of patients, respectively. Evaluation of LCBM receptor status is key to biomarker-driven targeted therapy for intracranial disease and awareness of subtype switching is critical for those patients treated with systemic therapy alone for intracranial disease.

Systematic review and meta-analysis of PD-L1 expression discordance between primary tumor and lung cancer brain metastasis.

BACKGROUND: Novel immunotherapeutic strategies targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis are often administered when metastatic tumors show PD-L1 positivity, even in the setting of lung cancer brain metastasis (LCBM). However, biological differences exist between primary tumors and metastatic sites. The objective of this study was to analyze rates of PD-L1 receptor discordance between primary tumors and LCBM. METHODS: A systematic review of studies of biopsied or resected LCBM evaluating PD-L1 discordance published in the Medline database was performed using PRISMA guidelines. Weighted random effects models were used to calculate pooled estimates. RESULTS: Six full-text articles (n = 230 patients) with a median of 32 patients in each study (range: 24-73) reported PD-L1 receptor expression analyses of both primary lung tumors and brain metastases and met inclusion criteria. The pooled estimate for tumor cell (TC) PD-L1 receptor discordance between primary tumors and LCBM was 19% (95% confidence interval [CI]: 10-27%). For PD-L1 receptor expression in tumor-infiltrating lymphocytes (TIL), the weighted pooled estimate for discordance was 21% (95% CI: 8-44%). For primary versus LCBM, the positive rates by expression levels of <1%, 1-50%, and >50% were 52% (95% CI: 30-73%) versus 56% (95% CI: 34-76%), 30% (95% CI: 22-40%) versus 20% (95% CI: 10-35%), and 15% (95% CI: 6-36%) versus 22% (95% CI: 15-31%) (P = .425), respectively. CONCLUSIONS: PD-L1 discordance occurs in ~20% of LCBM, with the greatest discordance in the 1-50% expression category. Although controversial, confirming discordance might be important for selection of immune checkpoint inhibitor therapy and in the analysis of patterns of failure after treatment.

Impact of MRI timing on tumor volume and anatomic displacement for brain metastases undergoing stereotactic radiosurgery.

BACKGROUND: The objective of this study was to evaluate the impact of the time interval between planning imaging and stereotactic radiosurgery (SRS) delivery on tumor volumes and spatial anatomic displacements of brain metastases (BM). METHODS: Consecutive patients diagnosed with BM treated with SRS over a 3-year period were evaluated. Only patients who underwent an institutionally standardized diagnostic MRI (MRI-1) and a treatment planning MRI (MRI-2) were included. The impact of histology, inter-scan time interval, lesion location, tumor volume, and diameter were evaluated on final lesion diameter, volume, anatomic displacement, and ultimate need for change in management (ie, expanding margins, rescanning). RESULTS: 101 patients (531 lesions) with a median inter-scan time interval of 8 days (range: 1-42 days) met the inclusion criteria. The median percentage increase in BM diameter and volume were 9.5% (IQR: 2.25%-24.0%) and 20% (IQR: 0.7%-66.7%). Overall, 147 lesions (27.7%) in 57 patients (56.4%) required a change in management. There was a statistically significant relationship between initial tumor diameter (cm) and change in management (OR: 2.69, 95% CI: 1.93-3.75; P < .001). Each day between MRI-1 and MRI-2 was associated with a change in management with an OR of 1.05 (95% CI: 1.03-1.07; P < .001). CONCLUSIONS: Changes in tumor diameter, volume, and spatial position occur as a function of time. Planning imaging for SRS is recommended to occur in close temporal proximity to treatment; for those with delays, a larger setup margin may need to be used to ensure tumor coverage and account for positional changes.