Tumor sound, auditory cues, and tissue pathology in glioma surgery: a proof-of-concept study

OBJECTIVE

Visual, tactile, and auditory cues are used during surgery to differentiate tissue type. Auditory cues in glioma surgery have not been studied previously. The objectives of this study were 1) to evaluate the feasibility of recording sound generated by the suction device during glioma surgery in matched tissue samples, and 2) to characterize the acoustic variation that occurs in different tissue samples.

METHODS

This was a prospective observational proof-of-concept study. Recordings were attempted in 20 patients in order meet the accrual target of 10 patients with matched sound and tissue data. For each patient, three 30- to 60-second recordings were made at these sites: normal white matter, infiltrative margin, and tumor. Tissue samples at each site were then reviewed by experienced neuropathologists, and agreement with surgical identification was estimated with the kappa statistic. Acoustic parameters were characterized for each sample.

RESULTS

Data from 20 patients were analyzed. Patient-related or technical issues resulted in missing data for 10 patients, but the final 10 patients had both audio and tissue data for analysis. Among all tissue samples, fair agreement was observed between surgeon identification and actual pathology (κ = 0.24, standard error 0.096, p = 0.006). Acoustic data suggested that 1) the acoustic stimulus is broadband, 2) acoustic features are somewhat consistent within cases, 3) high-entropy values indicate irregularity of sound over time, and 4) bimodal pitch distributions could differentially reflect cues of interest.

CONCLUSIONS

This study supports the feasibility of collecting intraoperative data on acoustic features during glioma surgery, and it provides an example of how an analysis could be performed to compare different types of tissues.

Association of Autologous Tumor Lysate-Loaded Dendritic Cell Vaccination With Extension of Survival Among Patients With Newly Diagnosed and Recurrent Glioblastoma: A Phase 3 Prospective Externally Controlled Cohort Trial

Importance

Glioblastoma is the most lethal primary brain cancer. Clinical outcomes for glioblastoma remain poor, and new treatments are needed.

Objective

To investigate whether adding autologous tumor lysate-loaded dendritic cell vaccine (DCVax-L) to standard of care (SOC) extends survival among patients with glioblastoma.

Design, Setting, and Participants

This phase 3, prospective, externally controlled nonrandomized trial compared overall survival (OS) in patients with newly diagnosed glioblastoma (nGBM) and recurrent glioblastoma (rGBM) treated with DCVax-L plus SOC vs contemporaneous matched external control patients treated with SOC. This international, multicenter trial was conducted at 94 sites in 4 countries from August 2007 to November 2015. Data analysis was conducted from October 2020 to September 2021.

Interventions

The active treatment was DCVax-L plus SOC temozolomide. The nGBM external control patients received SOC temozolomide and placebo; the rGBM external controls received approved rGBM therapies.

Main Outcomes and Measures

The primary and secondary end points compared overall survival (OS) in nGBM and rGBM, respectively, with contemporaneous matched external control populations from the control groups of other formal randomized clinical trials.

Results

A total of 331 patients were enrolled in the trial, with 232 randomized to the DCVax-L group and 99 to the placebo group. Median OS (mOS) for the 232 patients with nGBM receiving DCVax-L was 19.3 (95% CI, 17.5-21.3) months from randomization (22.4 months from surgery) vs 16.5 (95% CI, 16.0-17.5) months from randomization in control patients (HR = 0.80; 98% CI, 0.00-0.94; P = .002). Survival at 48 months from randomization was 15.7% vs 9.9%, and at 60 months, it was 13.0% vs 5.7%. For 64 patients with rGBM receiving DCVax-L, mOS was 13.2 (95% CI, 9.7-16.8) months from relapse vs 7.8 (95% CI, 7.2-8.2) months among control patients (HR, 0.58; 98% CI, 0.00-0.76; P < .001). Survival at 24 and 30 months after recurrence was 20.7% vs 9.6% and 11.1% vs 5.1%, respectively. Survival was improved in patients with nGBM with methylated MGMT receiving DCVax-L compared with external control patients (HR, 0.74; 98% CI, 0.55-1.00; P = .03).

Conclusions and Relevance

In this study, adding DCVax-L to SOC resulted in clinically meaningful and statistically significant extension of survival for patients with both nGBM and rGBM compared with contemporaneous, matched external controls who received SOC alone.

Trial Registration

ClinicalTrials.gov Identifier: NCT00045968.

Comparative Outcomes by Surgical Approach in Patients with Malignant Sinonasal Disease

Objective There is a paucity of data on comparative outcomes for open versus endoscopic surgery for patients with malignant sinonasal pathology. Most of the available studies are limited by a sample size <100 patients.

Design This is a retrospective cohort study.

Setting The findings of this study come from a single-institution tertiary care center from 2008 to 2019.

Participants In total, 199 patients who underwent surgery for malignant sinonasal disease participated in this study.

Main Outcome Measures The main outcome measures were perioperative complications and reoperation.

Results Patients in our sample had a mean age of 59.7 years (SD, 20.4). In total, 62% were male and 72% were white. An endoscopic-only approach was used in 41% of patients and an open or combined approach in 59% of patients. Squamous cell carcinoma was the most common pathology (43.0%), followed by sarcoma (9.5%), skin cancer (6.5%), sinonasal undifferentiated carcinoma (6.5%), and adenocarcinoma (5.5%). The all-cause complication rate was 14.6%. Patients with an open resection had a higher rate of intraoperative complications (5.9 vs. 0%; p = 0.043), postoperative complications (19.5 vs. 3.7%; p = 0.001), and all-cause complications (21.0 vs. 3.7%; p < 0.001). The likelihood of early reoperation (<6 months) or late reoperation (>6 months) did not significantly differ by surgical approach (p = 1.000 and 0.741, respectively).

Conclusion The endoscopic approach for resection of malignant sinonasal disease is viable for select patients and may be associated with a favorable complication rate compared with the open approach.

Brain Tumor Microenvironment and Angiogenesis in Melanoma Brain Metastases

BACKGROUND

High tumor-infiltrating lymphocytes (TILs) and hemorrhage are important prognostic factors in patients who have undergone craniotomy for melanoma brain metastases (MBM) before 2011 at the University of Pittsburgh Medical Center (UPMC). We have investigated the prognostic or predictive role of these histopathologic factors in a more contemporary craniotomy cohort from the University of North Carolina at Chapel Hill (UNC-CH). We have also sought to understand better how various immune cell subsets, angiogenic factors, and blood vessels may be associated with clinical and radiographic features in MBM.

METHODS

Brain tumors from the UPMC and UNC-CH patient cohorts were (re)analyzed by standard histopathology, tumor tissue imaging, and gene expression profiling. Variables were associated with overall survival (OS) and radiographic features.

RESULTS

The patient subgroup with high TILs in craniotomy specimens and subsequent treatment with immune checkpoint inhibitors (ICIs, n=7) trended to have longer OS compared to the subgroup with high TILs and no treatment with ICIs (n=11, p=0.059). Bleeding was significantly associated with tumor volume before craniotomy, high melanoma-specific expression of basic fibroblast growth factor (bFGF), and high density of CD31+αSMA- blood vessels. Brain tumors with high versus low peritumoral edema before craniotomy had low (17%) versus high (41%) incidence of brisk TILs. Melanoma-specific expression of the vascular endothelial growth factor (VEGF) was comparable to VEGF expression by TILs and was not associated with any particular prognostic, radiographic, or histopathologic features. A gene signature associated with gamma delta (gd) T cells was significantly higher in intracranial than same-patient extracranial metastases and primary melanoma. However, gdT cell density in MBM was not prognostic.

CONCLUSIONS

ICIs may provide greater clinical benefit in patients with brisk TILs in MBM. Intratumoral hemorrhage in brain metastases, a significant clinical problem, is not merely associated with tumor volume but also with underlying biology. bFGF may be an essential pathway to target. VEGF, a factor principally associated with peritumoral edema, is not only produced by melanoma cells but also by TILs. Therefore, suppressing low-grade peritumoral edema using corticosteroids may harm TIL function in 41% of cases. Ongoing clinical trials targeting VEGF in MBM may predict a lack of unfavorable impacts on TIL density and/or intratumoral hemorrhage.

Outcomes of Endoscopic Versus Open Skull Base Surgery in Pediatric Patients

OBJECTIVE/HYPOTHESIS

To characterize the pathology and outcomes of skull base surgery in the pediatric population by open versus endoscopic surgical approach.

STUDY DESIGN

Retrospective cohort study.

METHODS

A retrospective review of pediatric patients (<18 years) who underwent skull base surgery for nonmalignant disease from May 2000 to August 2019 was performed. Patient demographics, pathology, and operative characteristics by surgical approach were recorded and analyzed. Patients with a combined endoscopic/open approach were classified as open for the analysis.

RESULTS

Eighty-two pediatric skull base patients were identified with a mean age of 11.3 years (standard deviation 5.2). A purely endoscopic approach was used in 63 (77%) patients, a purely open approach was used in nine (11%) patients, and a combined open/endoscopic approach was used in 10 (12%) patients. The all-cause complication rate was 9.8%. There was no statistically significant difference in rate of complications between patients with an open versus endoscopic approach for resection (15.8% vs. 7.9%; P = .379). Risk of having a complication did not significantly vary by patient age. The odds of having a complication with an open approach was not statistically significant in a multivariable model adjusted for age, sex, race, intraoperative cerebrospinal fluid leak, tracheostomy requirement, and vascular flap use (odds ratio 2.76, 95% confidence interval 0.28-26.94; P = .383).

CONCLUSIONS

Our retrospective study demonstrates a similar risk of complication for open versus endoscopic approach to resection in pediatric skull base patients at our institution. Safety and feasibility of the endoscopic approach has previously been demonstrated in children, and this is the first study to directly compare outcomes with open approaches.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:996-1001, 2021.

Impacts of Surgery on Symptom Burden and Quality of Life in Pituitary Tumor Patients in the Subacute Post-operative Period

Background: Pituitary tumors are rare but are associated with significant symptoms that impact patients' quality of life (QOL). Surgery remains one of the most effective treatment options for long term disease control and symptom benefit, but symptom, and quality of life recovery in the subacute period has not been previously reported. This study aimed to better understand the impact of surgery on patients' symptom burden and QOL in the subacute post-surgical period. Methods: Twenty-three adult patients with pituitary tumors undergoing surgical resection at University of North Carolina Cancer Hospital were enrolled in this study. M.D. Anderson Symptom Inventory Brain Tumor Module, European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-BN20 questionnaires were collected pre- and 1-month post- surgical resection and differences were analyzed for individual and groups of symptoms and QOL using Wilcoxon signed-rank tests. Results: Twenty adult patients had both pre-operation and post-operation follow-up visits; 60% had functional pituitary adenomas. Seven symptoms including fatigue, memory, vision, numbness, speaking, appearance, and weakness were significantly improved at the 1-month post-operation visit while one symptom, sleep, worsened. Global Health Status/QOL measurements was improved minimally from 63 (SD 25) at pre-operation to 67 (SD 22) at 1-month post-operation without statistical significance. Conclusions: This study demonstrated a rapid improvement of many symptoms in the subacute post-operative period in pituitary tumor patients. Disturbed sleep was identified as the only symptom to worsen post-operatively, encouraging potential prospective interventions to improve sleep, and subsequently improve the QOL in pituitary tumor patients following surgical intervention.

MerTK as a therapeutic target in glioblastoma

Background

Glioma-associated macrophages and microglia (GAMs) are components of the glioblastoma (GBM) microenvironment that express MerTK, a receptor tyrosine kinase that triggers efferocytosis and can suppress innate immune responses. The aim of the study was to define MerTK as a therapeutic target using an orally bioavailable inhibitor, UNC2025.

Methods

We examined MerTK expression in tumor cells and macrophages in matched patient GBM samples by double-label immunohistochemistry. UNC2025-induced MerTK inhibition was studied in vitro and in vivo.

Results

MerTK/CD68+ macrophages increased in recurrent tumors while MerTK/glial fibrillary acidic protein-positive tumor cells did not. Pharmacokinetic studies showed high tumor exposures of UNC2025 in a syngeneic orthotopic allograft mouse GBM model. The same model mice were randomized to receive vehicle, daily UNC2025, fractionated external beam radiotherapy (XRT), or UNC2025/XRT. Although median survival (21, 22, 35, and 35 days, respectively) was equivalent with or without UNC2025, bioluminescence imaging (BLI) showed significant growth delay with XRT/UNC2025 treatment and complete responses in 19%. The responders remained alive for 60 days and showed regression to 1%-10% of pretreatment BLI tumor burden; 5 of 6 were tumor free by histology. In contrast, only 2% of 98 GBM mice of the same model treated with XRT survived 50 days and none survived 60 days. UNC2025 also reduced CD206+ macrophages in mouse tumor samples.

Conclusions

These results suggest that MerTK inhibition combined with XRT has a therapeutic effect in a subset of GBM. Further mechanistic studies are warranted.

Intra-cavity stem cell therapy inhibits tumor progression in a novel murine model of medulloblastoma surgical resection

Background

Cytotoxic neural stem cells (NSCs) have emerged as a promising treatment for Medulloblastoma (MB), the most common malignant primary pediatric brain tumor. The lack of accurate pre-clinical models incorporating surgical resection and tumor recurrence limits advancement in post-surgical MB treatments. Using cell lines from two of the 5 distinct MB molecular sub-groups, in this study, we developed an image-guided mouse model of MB surgical resection and investigate intra-cavity NSC therapy for post-operative MB.

Methods

Using D283 and Daoy human MB cells engineered to express multi-modality optical reporters, we created the first image-guided resection model of orthotopic MB. Brain-derived NSCs and novel induced NSCs (iNSCs) generated from pediatric skin were engineered to express the pro-drug/enzyme therapy thymidine kinase/ganciclovir, seeded into the post-operative cavity, and used to investigate intra-cavity therapy for post-surgical MB.

Results

We found that surgery reduced MB volumes by 92%, and the rate of post-operative MB regrowth increased 3-fold compared to pre-resection growth. Real-time imaging showed NSCs rapidly homed to MB, migrating 1.6-fold faster and 2-fold farther in the presence of tumors, and co-localized with MB present in the contra-lateral hemisphere. Seeding of cytotoxic NSCs into the post-operative surgical cavity decreased MB volumes 15-fold and extended median survival 133%. As an initial step towards novel autologous therapy in human MB patients, we found skin-derived iNSCs homed to MB cells, while intra-cavity iNSC therapy suppressed post-surgical tumor growth and prolonged survival of MB-bearing mice by 123%.

Conclusions

We report a novel image-guided model of MB resection/recurrence and provide new evidence of cytotoxic NSCs/iNSCs delivered into the surgical cavity effectively target residual MB foci.

First results on survival from a large Phase 3 clinical trial of an autologous dendritic cell vaccine in newly diagnosed glioblastoma

Background

Standard therapy for glioblastoma includes surgery, radiotherapy, and temozolomide. This Phase 3 trial evaluates the addition of an autologous tumor lysate-pulsed dendritic cell vaccine (DCVax^®-L) to standard therapy for newly diagnosed glioblastoma.

Methods

After surgery and chemoradiotherapy, patients were randomized (2:1) to receive temozolomide plus DCVax-L (n = 232) or temozolomide and placebo (n = 99). Following recurrence, all patients were allowed to receive DCVax-L, without unblinding. The primary endpoint was progression free survival (PFS); the secondary endpoint was overall survival (OS).

Results

For the intent-to-treat (ITT) population (n = 331), median OS (mOS) was 23.1 months from surgery. Because of the cross-over trial design, nearly 90% of the ITT population received DCVax-L. For patients with methylated MGMT (n = 131), mOS was 34.7 months from surgery, with a 3-year survival of 46.4%. As of this analysis, 223 patients are ≥ 30 months past their surgery date; 67 of these (30.0%) have lived ≥ 30 months and have a Kaplan-Meier (KM)-derived mOS of 46.5 months. 182 patients are ≥ 36 months past surgery; 44 of these (24.2%) have lived ≥ 36 months and have a KM-derived mOS of 88.2 months. A population of extended survivors (n = 100) with mOS of 40.5 months, not explained by known prognostic factors, will be analyzed further. Only 2.1% of ITT patients (n = 7) had a grade 3 or 4 adverse event that was deemed at least possibly related to the vaccine. Overall adverse events with DCVax were comparable to standard therapy alone.

Conclusions

Addition of DCVax-L to standard therapy is feasible and safe in glioblastoma patients, and may extend survival.

Trial registration Funded by Northwest Biotherapeutics; Clinicaltrials.gov number: NCT00045968; https://clinicaltrials.gov/ct2/show/NCT00045968?term=NCT00045968&rank=1; initially registered 19 September 2002

Increased Role of the Otolaryngologist in Endoscopic Pituitary Surgery: Endoscopic Hydroscopy of the Sella

Background

The aim of this study was to discuss the use of nasal irrigation and suction systems in endoscopic pituitary surgery to examine the sella and facilitate tumor removal. We describe a new technique of sellar exploration.

Methods

Following the endoscopic approach to the pituitary by the otolaryngology team, pituitary masses are resected. Then, the ClearESS nasal irrigation and suction system is used by the otolaryngology team to visualize the sella (“hydroscopy”). The combination of this ClearESS technology and angled endoscopes is used to scrutinize previously inaccessible areas of the tumor bed.

Results

Over 50 patients have undergone minimally invasive pituitary surgery via the endoscopic approach with postresection hydroscopy of the sella. The use of angled endoscopes in combination with the ClearESS technology greatly increased visualization of the sella, thereby facilitating complete tumor removal. There have been no complications associated with the use of hydroscopy.

Conclusion

The use of angled endoscopes in conjunction with hydroscopy increases visualization of the sella. The otolaryngologist plays a critical role in this examination with manipulation of the angled endoscopes. Therefore, the role of the otolaryngologist is extended beyond the approach to the pituitary.

Sellar Reconstruction: Is it Necessary?

Background

Sellar reconstruction is practiced routinely during the transsphenoidal approach to pituitary tumor resection. This practice exposes the patient to risks of donor site complications and may interfere with measuring postoperative tumor reduction. We propose that it is not a necessary component of transsphenoidal pituitary surgery in the absence of intraoperative cerebrospinal fluid (CSF) leak.

Methods

A retrospective chart review of 45 cases of minimally invasive pituitary surgery were reviewed. Twenty-eight cases were identified with no sellar reconstruction being performed. Age, sex, revision surgery, postoperative CSF leak, days with lumbar drain, meningitis, ophthalmoplegia, visual acuity loss, postoperative epistaxis, diabetes insipidus, development of empty sella syndrome, and length of stay were investigated in these cases.

Results

Twenty-three cases were the primary procedure and five cases were revision surgery. Complication rates were low and compared favorably with those reported in the literature. Five cases of transient diabetes insipidus occurred. There was one postoperative CSF leak that required 4 days with a lumbar drain. No cases of empty sella syndrome developed. There were no cases of meningitis. The average length of stay was 2.9 days.

Conclusion

Sellar reconstruction during transsphenoidal approach to pituitary tumor resection is not required for patients without evidence of an intraoperative CSF leak. This practice exposes the patient to the risks of donor site complications without reducing the rate of postoperative complications.

The Learning Curve in Minimally Invasive Pituitary Surgery

Background

Minimally invasive pituitary surgery (MIPS) is performed via an endoscopic transnasal transsphenoidal approach. This provides excellent illumination, visualization, and magnification of the operative field, in addition to avoiding complications associated with other approaches. In this study we examined the first 45 cases of MIPS to determine if a learning curve exists for this technique.

Methods

A retrospective chart review was performed of the first 45 cases of MIPS at a major academic medical center. Cases were divided into three groups of 15 patients each. Group characteristics including age, sex, and revision surgery were compared. Complication rates investigated included death, intracerebral hemorrhage, intraoperative cerebrospinal fluid leak, postoperative cerebrospinal fluid leak, use of lumbar drain, meningitis, postoperative epistaxis, ophthalmoplegia, visual impairment, and diabetes insipidus. Other factors examined included intraoperative blood loss, length of stay, and tumor histology. One way analysis of variance statistical analysis was used to determine the significance of differences between groups.

Results

Groups were comparable in respect to characteristics studied. Statistically significant (p < 0.05) differences in complication rates and other factors between groups were not shown. Complication rates are low.

Conclusion

This study does not establish a learning curve for our first 45 cases of MIPS. This finding supports the concept that an otolaryngology/neurosurgery team skilled in endoscopic techniques and pituitary surgery can safely transition from open approaches to an endoscopic approach in pituitary surgery.

Tumor-homing cytotoxic human induced neural stem cells for cancer therapy

Engineered neural stem cells (NSCs) are a promising approach to treating glioblastoma (GBM). The ideal NSC drug carrier for clinical use should be easily isolated and autologous to avoid immune rejection. We transdifferentiated (TD) human fibroblasts into tumor-homing early-stage induced NSCs (h-iNSC^TE), engineered them to express optical reporters and different therapeutic gene products, and assessed the tumor-homing migration and therapeutic efficacy of cytotoxic h-iNSC^TE in patient-derived GBM models of surgical and nonsurgical disease. Molecular and functional analysis revealed that our single-factor SOX2 TD strategy converted human skin fibroblasts into h-iNSC^TE that were nestin⁺ and expressed pathways associated with tumor-homing migration in 4 days. Time-lapse motion analysis showed that h-iNSC^TE rapidly migrated to human GBM cells and penetrated human GBM spheroids, a process inhibited by blockade of CXCR4. Serial imaging showed that h-iNSC^TE delivery of the proapoptotic agent tumor necrosis factor-α-related apoptosis-inducing ligand (TRAIL) reduced the size of solid human GBM xenografts 250-fold in 3 weeks and prolonged median survival from 22 to 49 days. Additionally, h-iNSC^TE thymidine kinase/ganciclovir enzyme/prodrug therapy (h-iNSC^TE-TK) reduced the size of patient-derived GBM xenografts 20-fold and extended survival from 32 to 62 days. Mimicking clinical NSC therapy, h-iNSC^TE-TK therapy delivered into the postoperative surgical resection cavity delayed the regrowth of residual GBMs threefold and prolonged survival from 46 to 60 days. These results suggest that TD of human skin into h-iNSC^TE is a platform for creating tumor-homing cytotoxic cell therapies for cancer, where the potential to avoid carrier rejection could maximize treatment durability in human trials.

Changing Natural History of HER2-Positive Breast Cancer Metastatic to the Brain in the Era of New Targeted Therapies

BACKGROUND

Given the wide adoption of human epidermal growth factor receptor 2 (HER2)-targeted therapies for advanced HER2-positive breast cancer, we studied the natural history of patients with HER2-positive breast cancer brain metastases (BCBM) over time.

PATIENTS AND METHODS

Patients with HER2-positive BCBM identified from a prospectively maintained database at the University of North Carolina were divided into 3 cohorts by year of BCBM diagnosis. Cohorts were selected by year of HER2-targeted therapy US Food and Drug Administration approval. Overall survival (OS), time to first metastasis, time to BCBM, and BCBM survival were estimated by the Kaplan-Meier method. Associations between OS after BCBM and clinical variables were assessed by Cox proportional hazards regression models.

RESULTS

One hundred twenty-three patients were identified. Median age was 51 years, and 58% were white and 31% African American. OS from initial breast cancer diagnosis improved over time: 3.6 years (95% confidence interval [CI], 2.8-6.1) in the 1998-2007 cohort, 6.6 years (95% CI, 4.5-8.6) in the 2008-2012 cohort, and 7.6 years (95% CI, 4.4-9.6) in the 2013-2015 cohort (P = .05). While time from initial diagnosis to first metastasis did not differ (P = .12), time to BCBM increased over time (2.6 years [95% CI, 1.3-3.5] for 1998-2007; 2.6 years [95% CI, 2.1-4.3] for 2008-2012, and 3.3 years [95% CI, 2.2-6] for 2013-2015; P = .05). Although OS from BCBM did not significantly differ by cohort, patients who received HER2-targeted therapy after BCBM had a prolonged OS (2.1 years [95% CI, 1.6-2.6] vs. 0.65 years [95% CI, 0.4-1.3]; P = .001).

CONCLUSION

OS from initial breast cancer diagnosis significantly improved over time for patients with HER2-positive breast cancer who develop BCBM, now exceeding 7 years; survival from BCBM diagnosis may now exceed 2 years.

Examination and prognostic implications of the unique microenvironment of breast cancer brain metastases

2072

Background: Brain metastases (BM) are an increasingly common consequence of breast cancer (BC). Knowledge of the microenvironment in primary BC and its impact on prognosis is evolving. A similar understanding of the microenvironment of BC metastases is lacking, particularly for the brain, where unique immune regulation governs stroma composition. Such features of the peri-tumoral landscape, i.e. high immune infiltrate and low hemorrhage, offer prognostic value in BM from melanoma. This study reports on 4 biomarkers, gliosis (glio), immune infiltrate (immune), hemorrhage (hem) and necrosis (nec), and their prognostic significance in BCBM. Methods: A biobank of 203 patients (pts) who underwent craniotomy between 1989-2013 was created across 4 sites. Glio, immune, and hem (grouped 0 v 1-3) and nec (0-2 v 3) were scored via H&E stain (0-3). Overall survival (OS (years)) from craniotomy was estimated using the Kaplan-Meier method; log-rank tests compared OS. Cox proportional hazards regression was used to evaluate prognostic value of the 4 biomarkers. Results: Mean age at primary BC diagnosis was 48 years (range 26-77). BCBM subtype (n = 158) was 36% HER2+, 26% HR+/HER2-, 38% HR-/HER2- (TN). Across all samples, expression was 82% glio, 45% immune, 82% hem, and 13% nec. Subtype differences were seen for nec (higher in TN, p < 0.01). Across all pts, expression of glio, immune, and hem was associated with improved OS (years): 1.08 v 0.62 (p = 0.03), 1.31 v 0.93 (p = 0.03), 1.07 v 0.92 (p = 0.1), respectively. Nec was associated with inferior OS: 0.38 v 1.12 (p = 0.01). The association with improved OS was maintained for glio in TN (p = 0.02), and immune (p = 0.001) and hem (p = 0.07) in HER2+. In a multivariable model for OS, adding the 4 biomarkers to traditional clinical variables (age, race, subtype) significantly improved the model fit (p < 0.001). Conclusions: Nec is a poor prognostic finding in BCBM across all subtypes. Glio confers superior prognosis in TN, while immune and hem correlate with superior prognosis in HER2+. A deeper understanding of the rich BCBM microenvironment both refines prognostic considerations for this pt population and may lead to future investigations of targeted immunotherapies in select subtypes of BCBM.

Chemosensitivity of IDH1-Mutated Gliomas Due to an Impairment in PARP1-Mediated DNA Repair

Mutations in isocitrate dehydrogenase (IDH) are the most prevalent genetic abnormalities in lower grade gliomas. The presence of these mutations in glioma is prognostic for better clinical outcomes with longer patient survival. In the present study, we found that defects in oxidative metabolism and 2-HG production confer chemosensitization in IDH1-mutated glioma cells. In addition, temozolomide (TMZ) treatment induced greater DNA damage and apoptotic changes in mutant glioma cells. The PARP1-associated DNA repair pathway was extensively compromised in mutant cells due to decreased NAD⁺ availability. Targeting the PARP DNA repair pathway extensively sensitized IDH1-mutated glioma cells to TMZ. Our findings demonstrate a novel molecular mechanism that defines chemosensitivity in IDH-mutated gliomas. Targeting PARP-associated DNA repair may represent a novel therapeutic strategy for gliomas. Cancer Res; 77(7); 1709-18. ©2017 AACR.

Multidisciplinary Management of Breast Cancer Brain Metastases

This review summarizes the most up-to-date approach to the multidisciplinary management of patients with breast cancer brain metastases. A brief overview of the epidemiology and biology of breast cancer brain metastasis is provided. The perspectives of radiation oncology, neurosurgery, and medical oncology-and landmark studies from each discipline-are all discussed. We also offer practical tips to help guide the treating physician, including data on antiseizure medications. Finally, we introduce the concept of a multidisciplinary clinic that combines input from medical and radiation oncology, neurosurgery, and support services, which we developed at the University of North Carolina as a coordinated and optimal approach to the management of patients with this complex disease.

Reconstruction of Skull Base Defects

"Endoscopic endonasal skull base surgery has dramatically changed and expanded over recent years due to significant advancements in instrumentation, techniques, and anatomic understanding. With these advances, the need for more robust skull base reconstructive techniques was vital. In this article, reconstructive options ranging from acellular grafts to vascular flaps are described, including the strengths, weaknesses, and common uses."

Core pathway mutations induce de-differentiation of murine astrocytes into glioblastoma stem cells that are sensitive to radiation but resistant to temozolomide

BACKGROUND

Glioma stem cells (GSCs) from human glioblastomas (GBMs) are resistant to radiation and chemotherapy and may drive recurrence. Treatment efficacy may depend on GSCs, expression of DNA repair enzymes such as methylguanine methyltransferase (MGMT), or transcriptome subtype.

METHODS

To model genetic alterations in human GBM core signaling pathways, we induced Rb knockout, Kras activation, and Pten deletion mutations in cortical murine astrocytes. Neurosphere culture, differentiation, and orthotopic transplantation assays were used to assess whether these mutations induced de-differentiation into GSCs. Genome-wide chromatin landscape alterations and expression profiles were examined by formaldehyde-assisted isolation of regulatory elements (FAIRE) seq and RNA-seq. Radiation and temozolomide efficacy were examined in vitro and in an allograft model in vivo. Effects of radiation on transcriptome subtype were examined by microarray expression profiling.

RESULTS

Cultured triple mutant astrocytes gained unlimited self-renewal and multilineage differentiation capacity. These cells harbored significantly altered chromatin landscapes that were associated with downregulation of astrocyte- and upregulation of stem cell-associated genes, particularly the Hoxa locus of embryonic transcription factors. Triple-mutant astrocytes formed serially transplantable glioblastoma allografts that were sensitive to radiation but expressed MGMT and were resistant to temozolomide. Radiation induced a shift in transcriptome subtype of GBM allografts from proneural to mesenchymal.

CONCLUSION

A defined set of core signaling pathway mutations induces de-differentiation of cortical murine astrocytes into GSCs with altered chromatin landscapes and transcriptomes. This non-germline genetically engineered mouse model mimics human proneural GBM on histopathological, molecular, and treatment response levels. It may be useful for dissecting the mechanisms of treatment resistance and developing more effective therapies.

ACTIVITY OF TRASTUZUMAB-EMTANSINE (TDM1) IN HER2-POSITIVE BREAST CANCER BRAIN METASTASES: A CASE SERIES

The incidence of breast cancer brain metastasis (BCBM) is increasing due in part to improved management of systemic disease and prolonged survival. Despite this growing population of patients, there exists little consensus for the treatment of HER2-positive BCBM. Lapatinib, the only brain permeable targeted agent for HER2-positive cancer, has demonstrated limited intracranial response rates and little improvement in progression free survival (PFS) for HER-2 positive patients. Size constraints are believed to prevent larger monoclonal antibodies, such as pertuzumab and trastuzumab, from crossing the blood brain barrier (BBB). However, emerging evidence reveals that the BBB is perturbed in the setting of metastases, allowing for improved penetrance of these larger targeted agents. The disrupted BBB may allow for passage of ado-trastuzumab emtansine (TDM1), though little clinical information about its activity in BCBM patients is currently known.

A Multidisciplinary Breast Cancer Brain Metastases Clinic: The University of North Carolina Experience

The University of North Carolina at Chapel Hill has created a clinic to provide medical and radiation oncology, neurosurgical, and supportive services to patients with breast cancer brain metastases. Of the 65 patients seen between January 2012 and January 2015, 78% returned for a follow-up visit and 32% were enrolled in a clinical trial. The clinic is a model that can be adapted at other centers.

Background.

Breast cancer brain metastasis (BCBM) confers a poor prognosis and is unusual in requiring multidisciplinary care in the metastatic setting. The University of North Carolina at Chapel Hill (UNC-CH) has created a BCBM clinic to provide medical and radiation oncology, neurosurgical, and supportive services to this complex patient population. We describe organization and design of the clinic as well as characteristics, treatments, and outcomes of the patients seen in its first 3 years.

Methods.

Clinical and demographic data were collected from patients in a prospectively maintained database. Descriptive statistics are reported as percentages and means. The Kaplan-Meier method was used to estimate time-to-event outcomes.

Results.

Sixty-five patients were seen between January 2012 and January 2015. At the time of presentation to the BCBM clinic, most patients (74%) had multiple (≥2) brain metastases and had received prior systemic (77%) and whole-brain radiation therapy and/or central nervous system stereotactic radiosurgery (65%) in the metastatic setting. Seventy-eight percent returned for a follow-up visit; 32% were enrolled in a clinical trial. Median time from diagnosis of brain metastasis to death was 2.11 years (95% confidence interval [CI] 1.31–2.47) for all patients, 1.15 years (95% CI 0.4–2.43) for triple-negative breast cancer, 1.31 years (95% CI 0.51–2.52) for hormone receptor-positive/HER2− breast cancer, and 3.03 years (95% CI lower limit 1.94, upper limit not estimable) for HER2+ breast cancer (p = .0037).

Conclusion.

Patients with BCBM have unique and complex needs that require input from several oncologic disciplines. The development of the UNC-CH multidisciplinary BCBM clinic is a model that can be adapted at other centers to provide coordinated care for patients with a challenging and complex disease.

Implications for Practice:

Patients with breast cancer brain metastases often require unique multidisciplinary care to meet the numerous and uncommon challenges associated with their conditions. Here, the development and characteristics of a clinic designed specifically to provide for the multidisciplinary needs of patients with breast cancer brain metastases are described. This clinic may serve as a model for other institutions interested in creating specialty clinics with similar objectives.

Endoscopic sinonasal meningoencephalocele repair: a 13-year experience with stratification by defect and reconstruction type

OBJECTIVE

Sinonasal meningoencephalocele is a rare defect, with varying etiologies and treatment strategies. Here we present the largest published series from a single institution of patients with endoscopic repair. The primary goal is to examine rates of success with consideration to accompanying patient demographic data. The secondary goal is to report the results stratified by defect and reconstruction type.

DESIGN

Retrospective consecutive case series.

SETTING

Tertiary care academic center.

SUBJECTS AND METHODS

Consecutive patients with CPT codes for skull base meningoencephalocele repair between May 2000 and March 2013 were reviewed. Patients who specifically had sinonasal defects were included.

RESULTS

During the study period, 149 cases of sinonasal meningoencephaloceles were managed in 133 patients. Mean follow-up was 21.3 months (range, 0-116). There was a success rate of 88% for initial repair, with mean recurrence time of 8.3 months (range, 0-38), and a success rate of 93.8% for initial recurrence surgery, with 99.3% of ultimate successful repair. All cases were repaired endoscopically. Recurrence rate was not significantly related to location of defect (P = .682), size of defect (P = .434), particular reconstruction technique (P = .163), or etiology (trauma, P = .070). Overall complication rate was 11.3%.

CONCLUSION

Endoscopic sinonasal meningoencephalocele repair has excellent long-term results and may be considered as a primary approach. Surgeon comfort with a particular technique should be the most important factor used to guide choice of reconstruction.

Endoscopic endonasal approaches to infratemporal fossa tumors: a classification system and case series

OBJECTIVES/HYPOTHESIS

To propose a clinically applicable anatomic classification system describing three progressive endoscopic endonasal approaches (EEAs) to the infratemporal fossa (ITF) and their potential sequelae. Overall feasibility and outcomes of these approaches are presented through a consecutive case series.

STUDY DESIGN

Description of classification system for EEAs to the ITF and case series.

METHODS

A classification system of EEAs to ITF tumors was created based on the senior author's clinical experience and cadaveric dissection. A retrospective chart review of 21 child and adult patients with primary ITF tumors treated by these approaches from 2008 to 2012 at a tertiary-care academic medical center was conducted.

RESULTS

Three progressive EEAs to ITF tumors were defined: 1) a transpterygopalatine fossa approach, 2) a transmedial pterygoid plate approach, and 3) a translateral pterygoid plate approach. Twenty-one patients treated with these approaches were identified consecutively, with a mean age of 44.2 years (range, 11-79 years). Tumors primarily involving the pterygopalatine fossa and not the ITF were excluded. Pathology included three advanced juvenile nasopharyngeal angiofibromas, three adenoid cystic carcinomas, two recurrent inverted papillomas, two trigeminal schwannomas, and 11 other diverse skull base pathologies. No intraoperative or postoperative complications occurred, with a mean follow-up of 21.5 months (range, 1-55 months). Expected potential sequelae such as V2/palatal numbness, Eustachian tube dysfunction, and trismus occurred in 10/21 patients.

CONCLUSIONS

EEAs to ITF tumors are technically feasible with low risk of complications for well-selected patients. The proposed classification system is useful for anticipating potential sequelae for each approach.

A multicenter retrospective study of frameless robotic radiosurgery for intracranial arteriovenous malformation

Introduction: CT-guided, frameless radiosurgery is an alternative treatment to traditional catheter-angiography targeted, frame-based methods for intracranial arteriovenous malformations (AVMs). Despite the widespread use of frameless radiosurgery for treating intracranial tumors, its use for treating AVM is not-well described.

Methods: Patients who completed a course of single fraction radiosurgery at The University of North Carolina or Georgetown University between 4/1/2005–4/1/2011 with single fraction radiosurgery and received at least one follow-up imaging study were included. All patients received pre-treatment planning with CTA ± MRA and were treated on the CyberKnife (Accuray) radiosurgery system. Patients were evaluated for changes in clinical symptoms and radiographic changes evaluated with MRI/MRA and catheter-angiography.

Results: Twenty-six patients, 15 male and 11 female, were included in the present study at a median age of 41 years old. The Spetzler-Martin grades of the AVMs included seven Grade I, 12 Grade II, six Grade III, and one Grade IV with 14 (54%) of the patients having a pre-treatment hemorrhage. Median AVM nidal volume was 1.62 cm³ (0.57–8.26 cm³) and was treated with a median dose of 1900 cGy to the 80% isodose line. At median follow-up of 25 months, 15 patients had a complete closure of their AVM, 6 patients had a partial closure, and 5 patients were stable. Time since treatment was a significant predictor of response, with patients experience complete closure having on average 11 months more follow-up than patients with partial or no closure (p = 0.03). One patient experienced a post-treatment hemorrhage at 22 months.

Conclusion: Frameless radiosurgery can be targeted with non-invasive MRI/MRA and CTA imaging. Despite the difficulty of treating AVM without catheter angiography, early results with frameless, CT-guided radiosurgery suggest that it can achieve similar results to frame-based methods at these time points.

The volumetric response of brain metastases after stereotactic radiosurgery and its post-treatment implications

BACKGROUND

Changes in tumor volume are seen on magnetic resonance imaging within weeks after stereotactic radiosurgery (SRS), but it remains unclear what clinical outcomes early radiological changes portend.

OBJECTIVE

We hypothesized that rapid, early reduction in tumor volume post-SRS is associated with prolonged local control and favorable clinical outcome.

METHODS

A retrospective review of patients treated with CyberKnife SRS for brain metastases at the University of North Carolina from 2007 to 2009 was performed. Patients with at least 1 radiological follow-up, minimal initial tumor volume of 0.1 cm, no previous focal radiation, and no recent whole-brain radiation therapy were eligible for inclusion.

RESULTS

Fifty-two patients with 100 metastatic brain lesions were analyzed and had a median follow-up of 15.6 months (range, 2-33 months) and a median of 2 (range, 1-8) metastatic lesions. In treated metastases in which there was a significant tumor volume reduction by 6 or 12 weeks post-SRS, there was no local progression for the duration of the study. Furthermore, patients with metastases that did not reduce in volume by 6 or 12 weeks post-SRS were more likely to require corticosteroids (P = .01) and to experience progression of neurological symptoms (P = .003).

CONCLUSION

Significant volume reductions of brain metastases measured at either 6 or 12 weeks post-SRS were strongly associated with prolonged local control. Furthermore, early volume reduction was associated with less corticosteroid use and stable neurological symptoms.

Endoscopic endonasal transclival approaches: case series and outcomes for different clival regions

Objective Transclival endoscopic endonasal approaches to the skull base are novel with few published cases. We report our institution's experience with this technique and discuss outcomes according to the clival region involved. Design Retrospective case series. Setting Tertiary care academic medical center Participants All patients who underwent endoscopic endonasal transclival approaches for skull base lesions from 2008 to 2012. Main Outcome Measures Pathologies encountered, mean intraoperative time, intraoperative complications, gross total resection, intraoperative cerebrospinal fluid (CSF) leak, postoperative CSF leak, postoperative complications, and postoperative clinical course. Results A total of 49 patients underwent 55 endoscopic endonasal transclival approaches. Pathology included 43 benign and 12 malignant lesions. Mean follow-up was 15.4 months. Mean operative time was 167.9 minutes, with one patient experiencing an intraoperative internal carotid artery injury. Of the 15 cases with intraoperative cerebrospinal fluid (CSF) leaks, 1 developed postoperative CSF leak (6.7%). There were six other postoperative complications: four systemic complications, one case of meningitis, and one retropharyngeal abscess. Gross total resection was achieved for all malignancies approached with curative intent. Conclusions This study provides evidence that endoscopic endonasal transclival approaches are a safe and effective strategy for the surgical management of a variety of benign and malignant lesions. Level of Evidence 4.

Beyond the nasoseptal flap: outcomes and pearls with secondary flaps in endoscopic endonasal skull base reconstruction

OBJECTIVES/HYPOTHESIS

Endoscopic endonasal skull base surgery defects require effective reconstruction. Although the nasoseptal flap (NSF) has become our institution's workhorse for large skull base defects with cerebrospinal fluid (CSF) leaks, situations where it is unavailable require secondary flaps. Clinical outcomes, pearls and pitfalls, and an algorithm will be presented for these secondary flaps.

STUDY DESIGN

Clinical case series.

METHODS

Medical records of all endoscopic endonasal skull base surgeries at a tertiary care academic medical center were reviewed for skull base defect type, reconstruction method, CSF leak rate, and flap necrosis rate.

RESULTS

Of 330 flaps for reconstructing endoscopic endonasal skull base defects, secondary flaps were used in 34 cases (10%). These included 16 endoscopic-assisted pericranial flaps, seven tunneled temporoparietal fascia flaps, three inferior turbinate flaps, two middle turbinate flaps, two anterior lateral nasal wall flaps, two palatal flaps, one occipital flap, and one facial artery buccinator flap. There were 19 anterior cranial fossa defects, 10 clival defects, three sellar defects, and one frontal and one lateral orbit/middle fossa defect. Twenty-five of the 34 cases (73.5%) had either prior or postoperative radiation therapy. The most common pathology was sinonasal cancer, with 16 cases (47.1%). The postoperative CSF leak rate was 3.6% due to one middle turbinate flap necrosis.

CONCLUSIONS

Secondary flaps for skull base reconstruction can be harvested with minimally invasive techniques and demonstrate excellent success rates (97%) that are comparable to that of the NSF (>95%). Multiple flaps for complex skull base defects should be in the armamentarium of comprehensive skull base surgery centers.

LEVEL OF EVIDENCE

4.

The impact of radiosurgery fractionation and tumor radiobiology on the local control of brain metastases

Object

Experience with whole-brain radiation therapy for metastatic tumors in the brain has identified a subset of tumors that exhibit decreased local control with fractionated regimens and are thus termed radioresistant. With the advent of frameless radiosurgery, fractionated radiosurgery (2–5 fractions) is being used increasingly for metastatic tumors deemed too large or too close to crucial structures to be treated in a single session. The authors retrospectively reviewed metastatic brain tumors treated at 2 centers to analyze the dependency of local control rates on tumor radiobiology and dose fractionation.

Methods

The medical records of 214 patients from 2 institutions with radiation-naive metastatic tumors in the brain treated with radiosurgery given either as a single dose or in 2–5 fractions were analyzed retrospectively. The authors compared the local control rates of the radiosensitive with the radioresistant tumors after either single-fraction or fractionated radiosurgery.

Results

There was no difference in local tumor control rates in patients receiving single-fraction radiosurgery between radioresistant and radiosensitive tumors (p = 0.69). However, after fractionated radiosurgery, treatment for radioresistant tumors failed at a higher rate than for radiosensitive tumors with an OR of 5.37 (95% CI 3.83–6.91, p = 0.032).

Conclusions

Single-fraction radiosurgery is equally effective in the treatment of radioresistant and radiosensitive metastatic tumors in the brain. However, fractionated stereotactic radiosurgery is less effective in radioresistant tumor subtypes. The authors recommend that radioresistant tumors be treated in a single fraction when possible and techniques for facilitating single-fraction treatment or dose escalation be considered for larger radioresistant lesions.

Preservation of neurocognitive function and local control of 1 to 3 brain metastases treated with surgery and carmustine wafers

Background

Neurosurgical resection and whole-brain radiation therapy (WBRT) are accepted treatments for single and oligometastatic cancer to the brain. To avoid the decline in neurocognitive function (NCF) linked to WBRT, the authors conducted a prospective, multicenter, phase 2 study to determine whether surgery and carmustine wafers (CW), while deferring WBRT, could preserve NCF and achieve local control (LC).

Methods

NCF and LC were measured in 59 patients who underwent resection and received CW for a single (83%) or dominant (oligometastatic, 2 to 3 lesions) metastasis and received stereotactic radiosurgery (SRS) for tiny nodules not treated with resection plus CW. Preservation of NCF was defined as an improvement or a decline ≤1 standard deviation from baseline in 3 domains: memory, executive function, and fine motor skills, evaluated at 2-month intervals.

Results

Significant improvements in executive function and memory occurred throughout the 1-year follow-up. Preservation or improvement of NCF occurred in all 3 domains for the majority of patients at each of the 2-month intervals. NCF declined in only 1 patient. The chemowafers were well tolerated, and serious adverse events were reversible. There was local recurrence in 28% of the patients at 1-year follow-up.

Conclusions

Patients with brain metastases had improvements in their cognitive trajectory, especially memory and executive function, after treatment with resection plus CW. The rate of LC (78%) was comparable to historic rates of surgery with WBRT and superior to reports of WBRT alone. For patients who undergo resection for symptomatic or large-volume metastasis or for tissue diagnosis, the addition of CW can be considered as an option.

Stereotactic radiosurgery for single brain metastases from non-small cell lung cancer: progression of extracranial disease correlates with distant intracranial failure

BACKGROUND

Limited data exist regarding management of patients with a single brain lesion with extracranial disease due to non-small cell lung cancer (NSCLC).

METHODS

Eighty-eight consecutive patients with a single brain lesion from NSCLC in the presence of extracranial disease were treated with stereotactic radiosurgery (SRS) alone. Local control (LC), distant intracranial failure (DIF), overall survival (OS), and toxicity were assessed. The logrank test was used to identify prognostic variables.

RESULTS

Median OS was 10.6 months. One-year DIF was 61%; LC 89%. Treatments were delivered in 1-5 fractions to median BED10 = 60 Gy. Five patients developed radionecrosis. Factors associated with shortened OS included poor performance status (PS) (p = 0.0002) and higher Recursive Partitioning Analysis class (p = 0.017). For patients with PS 0, median survival was 22 months. DIF was associated with systemic disease status (progressive vs. stable) (p = 0.0001), as was BED (p = 0.021) on univariate analysis, but only systemic disease (p = 0.0008) on multivariate analysis.

CONCLUSIONS

This study identifies a patient population that may have durable intracranial control after treatment with SRS alone. These data support the need for prospective studies to optimize patient selection for up-front SRS and to characterize the impact of DIF on patients' quality of life.

Predicting Survival in Patients With Brain Metastases Treated With Radiosurgery Using Artificial Neural Networks

BACKGROUND:

Artificial neural networks (ANNs) excel at analyzing challenging data sets and can be exceptional tools for decision support in clinical environments. The present study pilots the use of ANNs for determining prognosis in neuro-oncology patients.

OBJECTIVE:

To determine whether ANNs perform better at predicting 1-year survival in a group of patients with brain metastasis compared with traditional predictive tools.

METHODS:

ANNs were trained on a multi-institutional data set of radiosurgery patients to predict 1-year survival on the basis of several input factors. A single ANN, an ensemble of 5 ANNs, and logistic regression analyses were compared for efficacy. Sensitivity analysis was used to identify important variables in the ANN model.

RESULTS:

A total of 196 patients were divided up into training, testing, and validation data sets consisting of 98, 49, and 49 patients, respectively. Patients surviving at 1 year tended to be female (P = .001) and of good performance status (P = .01) and to have favorable primary tumor histology (P = .001). The pooled voting of 5 ANNs performed significantly better than the multivariate logistic regression model (P = .02), with areas under the curve of 84% and 75%, respectively. The ensemble also significantly outperformed 2 commonly used prognostic indexes. Primary tumor subtype and performance status were identified on sensitivity analysis to be the most important variables for the ANN.

CONCLUSION:

ANNs outperform traditional statistical tools and scoring indexes for predicting individual patient prognosis. Their facile implementation, robustness in the presence of missing data, and ability to continuously learn make them excellent choices for use in complicated clinical environments.

Comparison of fractionated and single session radiosurgery for radiation resistant brain metastases

2091

Background: Melanoma and renal cell carcinoma are commonly called radiation resistant tumors due to the decreased response rate to traditional radiation (1.8-2 Gy /Fraction). Large brain metastases from radioresistant primaries are clinical challenges. This study examines the impact of fractionation on the treatment of intracranial metastases from radiation resistant tumors. Methods: Patients with a primary diagnosis of melanoma or renal cell carcinoma and intracranial metastases who completed treatment at The University of North Carolina with frameless robotic radiosurgery between 2007-2011 were retrospectively analyzed. Patients were treated with either single or 3-5 fractions depending on volume. The study’s primary endpoints were overall survival (OS) and local control (LC), and its secondary endpoint was patient steroid requirements. Outcomes data and pre-treatment variables were analyzed for significance using appropriate non-parametric tests. Results: 25 patients were included in the single fraction arm and 13 patients in the multi-fraction arm, and both had equivalent pre-treatment characteristics with the exception of tumor volume which was larger in the multi-fraction arm (p=0.01). At a median follow-up of 4.7 months (range, 1.8-11.6), the median OS for all patients was 6.2 months. One year survival was 35.1% and 5 patients (13%) had local failures at a median time to local failure of 5.5 months. Patients in the multi-fraction arm failed at a higher rate (10.5%) than patients in the single fraction arm (2.6%) (p=0.04), but there was no difference in OS (p=0.34). There was no difference between pre-treatment and post-treatment steroid requirements between the two arms (p=0.351). Conclusions: Fractionation is intended to facilitate radiosurgery in large tumors by limiting high doses of radiation to a large portion of normal brain. In our study of radioresistant intracranial metastases, large tumors receiving multi-fraction radiosurgery had decreased local control with no difference in toxicity or OS. These results suggest a need for either dose escalation, or combination therapy designed to reduce tumor size (resection or aspiration) in order to facilitate single fraction treatment.

Phosphatidylinositol 3-kinase pathway activation in breast cancer brain metastases

INTRODUCTION

Activation status of the phosphatidylinositol 3-kinase (PI3K) pathway in breast cancer brain metastases (BCBMs) is largely unknown. We examined expression of phospho(p)-AKT, p-S6, and phosphatase and tensin homologue (PTEN) in BCBMs and their implications for overall survival (OS) and survival after BCBMs. Secondary analyses included PI3K pathway activation status and associations with time to distant recurrence (TTDR) and time to BCBMs. Similar analyses were also conducted among the subset of patients with triple-negative BCBMs.

METHODS

p-AKT, p-S6, and PTEN expression was assessed with immunohistochemistry in 52 BCBMs and 12 matched primary BCs. Subtypes were defined as hormone receptor (HR)+/HER2-, HER2+, and triple-negative (TNBC). Survival analyses were performed by using a Cox model, and survival curves were estimated with the Kaplan-Meier method.

RESULTS

Expression of p-AKT and p-S6 and lack of PTEN (PTEN-) was observed in 75%, 69%, and 25% of BCBMs. Concordance between primary BCs and matched BCBMs was 67% for p-AKT, 58% for p-S6, and 83% for PTEN. PTEN- was more common in TNBC compared with HR+/HER2- and HER2+. Expression of p-AKT, p-S6, and PTEN- was not associated with OS or survival after BCBMs (all, P > 0.06). Interestingly, among all patients, PTEN- correlated with shorter time to distant and brain recurrence. Among patients with TNBC, PTEN- in BCBMs was associated with poorer overall survival.

CONCLUSIONS

The PI3K pathway is active in most BCBMs regardless of subtype. Inhibition of this pathway represents a promising therapeutic strategy for patients with BCBMs, a group of patients with poor prognosis and limited systemic therapeutic options. Although expression of the PI3K pathway did not correlate with OS and survival after BCBM, PTEN- association with time to recurrence and OS (among patients with TNBC) is worthy of further study.

Comparative analysis of cost of endoscopic endonasal minimally invasive and sublabial-transseptal approaches to the pituitary

BACKGROUND

Two surgical approaches to the pituitary are commonly used: the sublabial-transseptal (SLTS) approach using microscopy and the endonasal endoscopic minimally invasive (MIPS) approach. Although outcomes are similar for both procedures, MIPS has become increasingly prevalent over the last 15 years. Limited cost analysis data comparing the 2 alternatives are available.

METHODS

A retrospective analysis of cost and volume data was performed using data from the published literature and University of North Carolina at Chapel Hill (UNC) Hospitals. A sensitivity analysis of the parameters was used to evaluate the uncertainty in parameter estimates.

RESULTS

The total cost in real dollars ranges from $11,438 to $12,513 and $18,095 to $21,005 per patient per procedure for MIPS and SLTS, respectively, with a cost difference ranging between $5582 and $9567 per patient per procedure. The sensitivity analysis indicates that the total cost for MIPS is most sensitive to: (1) average length of stay, (2) nursing costs, and (3) number of total complications, whereas the total cost for SLTS is most sensitive to: (1) average length of stay, (2) nursing cost, and (3) operating time. MIPS is less costly than SLTS between 94% and 98% of the time.

CONCLUSION

The results indicate that MIPS is less costly than SLTS at a large academic center. Future research should compare the outcomes and quality of life (QoL) associated with the 2 surgeries to improve the data used to determine the cost-effectiveness of MIPS compared to SLTS.

Approach-specific multi-grid anatomical modeling for neurosurgery simulation with public-domain and open-source software

We present on-going work on multi-resolution sulcal-separable meshing for approach-specific neurosurgery simulation, in conjunction multi-grid and Total Lagrangian Explicit Dynamics finite elements. Conflicting requirements of interactive nonlinear finite elements and small structures lead to a multi-grid framework. Implications for meshing are explicit control over resolution, and prior knowledge of the intended neurosurgical approach and intended path. This information is used to define a subvolume of clinical interest, within some distance of the path and the target pathology. Restricted to this subvolume are a tetrahedralization of finer resolution, the representation of critical tissues, and sulcal separability constraint for all mesh levels.

Abstract P1-14-01: Phosphatidylinositol 3-Kinase (PI3K) Pathway Activation in Breast Cancer Brain Metastases

Background:

Brain metastases (BM) are a devastating consequence of advanced breast cancer (BC) for which novel, targeted therapies are urgently needed. The PI3K pathway plays a critical role in the initiation and progression of BC. Alterations in this pathway are implicated in approximately 50% of BC. The role of PI3K activation in BCBM has yet to be explored. Material and Methods:

Under IRB approval (UNC and Duke), we established a clinically-annotated tumor bank including 54 BCBM and 15 matched primary BC. Activation of the PI3K pathway including pAKT, pS6K, and PTEN was assessed via immunohistochemistry (IHC, score 0-3+). BC subtype was assigned by IHC: HR+ (hormone receptor, ER+ and/or PR+)/HER2-, triple-negative (TN; ER-/PR-/HER2-), and HR +or-/HER2+. Overall survival (OS), recurrence patterns and survival following BM was evaluated by the Kaplan-Meier method and compared by the log-rank test.

Results:

Median age was 48 years (range 26-72). Sixty-eight percent of patients (pts) were Caucasian, 30% African-American, and 2% other ethnicities. At median follow-up of 5.9 years (yrs), 70% (38/54) of pts had died. BC subtype was confirmed among 47 pts: 30% (14/47) HR+/HER2-, 45% (21/47) TN and 25% (12/47) HR +or-/HER2+. Subtype concordance between primary BC and BM was 89% (8/9). High expression (IHC score 2-3+) of pAKT and pS6K was observed in 50% (27/54) and 72% (38/54) of the BCBM, respectively. Low expression of PTEN (IHC score 0-1) was observed in 31% (17/54) of BCBM. Concordance of PI3K biomarkers between primary BC and matched BCBM was 47% (7/15), 40% (6/15) and 80% (12/15) for pAKT, pS6K and PTEN, respectively. Both gain and loss of protein expression between primary BC and BCBM was observed in each biomarker evaluated. No significant correlation between BC subtypes and activation status of the PI3K pathway (IHC score 0-1 vs. 2-3+) was observed for pAKT, pS6K or PTEN. Median OS was 7.09 yrs (3.52, 9.21), 4.27 yrs (95% CI 1.84, 5.18), and not reached (NR) for HR+/HER2-, TN and HR +or-/HER2+, respectively (p=0.009). Median OS after BCBM diagnosis was 1.54 yrs (0.27, 2.45), 0.91 yrs (0.51, 1.49) and NR for HR+/HER2-, TN and HR +or-/HER2+, respectively (p=0.0003). Expression (0-1+ vs. 2-3+) of pAKT and pS6K in BCBM was not predictive of OS, time to BCBM recurrence or survival after BCBM (all P&gt;0.1). Although not predictive of inferior survival following BCBM (1.2 vs. 1.5 yrs, p=0.7), low expression (0-1+ vs. 2-3+) of PTEN in BCBM predicted for inferior OS from primary BC diagnosis (5.1 vs. 6.3 yrs, p=0.03) and shorter time to BCBM (2.5 vs. 3.4 yrs, p=0.008). Conclusions:

The PI3K pathway is active in most BCBM regardless of subtype. Considerable discordance exists between PI3K pathway biomarkers in the primary BC and BCBM from the same patient. Low expression of PTEN in BCBM may be prognostic. Given that small molecule inhibitors of the PI3K pathway in clinical development cross the blood brain barrier, inhibition of the PI3K pathway represents a promising therapeutic strategy for a group of patients whose prognosis is poor and for whom systemic therapies are limited.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-14-01.

The prognostic contribution of clinical breast cancer subtype, age, and race among patients with breast cancer brain metastases

BACKGROUND

Brain metastases (BM) arising from triple-negative breast cancer (TNBC) portend a poor prognosis. TNBC is more common in premenopausal and African-American (AA) patients; both of these characteristics also confer a poor prognosis. In a single-institution cohort study, the authors attempted to determine whether the inferior outcome noted with TNBC brain metastases is more reflective of a higher risk population or the subtype itself.

METHODS

The University of North Carolina Breast Cancer Database identified patients with BC brain metastases who were diagnosed between 1988 and 2008. BC subtype was assigned by immunohistochemistry: hormone receptor (HR) positive (+);(HR, estrogen receptor [ER]+ and/or progesterone receptor [PR]+)/human epidermal growth factor receptor 2 (HER2) negative (-), HR+/HER2+, HR-/HER2+, and TN (ER-/PR-/HER2-). Survival and disease recurrence patterns were evaluated by subtype, patient age (<40 years vs ≥40 years), and race (AA vs non-AA) using the Kaplan-Meier method and Cox regression analysis.

RESULTS

Among 119 patients with BC brain metastases, 33% were AA and 31% were aged <40 years. BC subtype was confirmed in 98 patients (30% with HR+/HER2-, 21% with HR+/HER2+, 18% with HR-/HER2+, and 31% with TNBC). Survival after BM was found to be impacted by subtype (P = .002), and was shortest for patients with TNBC (0.24 years; 95% confidence interval, 0.17 years-0.48 years). There were no age-specific (P = .84) or race-specific (P = .09) differences in survival noted after brain metastases; stratification of BC subtypes by age and race revealed no difference (all, P > .1). The receipt of systemic therapy after BC brain metastases was found to be an important predictor of survival after BC brain metastases (hazard ratio, 0.29; P = .002) when adjusted for race, age, number of central nervous system lesions, and BC subtype.

CONCLUSIONS

TNBC confers a high risk of death after brain metastases regardless of patient race and age, supporting the need for novel agents capable of controlling both intracranial and extracranial TNBC across all races and ages.

Anatomical considerations for endoscopic endonasal skull base surgery in pediatric patients

OBJECTIVES/HYPOTHESIS

Pediatric skull base surgery is limited by several boney sinonasal landmarks that must be overcome prior to tumor dissection. When approaching a sellar or parasellar tumor, the piriform aperture, sphenoid sinus pneumatization, and intercarotid distances are areas of potential limitation. Quantitative pediatric anatomical measurements relevant to skull base approaches are lacking. Our goal was to use radio-anatomic analysis of computed tomography scans to determine anatomical limitations for trans-sphenoidal approaches in pediatric skull base surgery.

STUDY DESIGN

A radio-anatomic cross-sectional survey.

METHODS

Measurements included the diameter of the piriform aperture, posterior extent of sphenoid sinus pneumatization, and intercarotid distances on fine-cut, age-stratified maxillofacial scans. Fifty pediatric (<18 years of age) and 10 adult patients were equally subdivided into seven age groups and compared to determine age-related differences in sphenoid sinus pneumatization, skull base thicknesses, and intercarotid distances.

RESULTS

Piriform aperture width was significantly greater in adults than in patients under age 7 years (P <or= .002). Three fourths of the planum and sellar face and one half of the sellar floor were pneumatized by ages 6 to 7 years. Superior clival pneumatization was not evident until 12 years of age. Clival intercarotid distances were not different among groups. Drilling distances for trans-planar, trans-sellar, and trans-clival approaches are described.

CONCLUSIONS

Several potential anatomic limits must be considered in pediatric skull base surgery, and these vary according to age. Piriform aperture is likely a limit only in the youngest patients (under 2 years). Sphenoid pneumatization to the planum and sella start at 3 years and complete by age 10 years. Clival intercarotid distances do not change significantly and are not prohibitively narrow in any age group.

Cost effectiveness of a clinical pharmacist on a neurosurgical team

OBJECTIVE

In 1999, the Society of Critical Care Medicine formally recognized that pharmacists were essential for the provision of high quality care to the critically ill population. This study is a brief quantitative analysis of the benefit provided by a clinical pharmacist in a multidisciplinary neurosurgical setting.

METHODS

Patients admitted to the neurosurgical service in the 2 years before and 2 years after the implementation of dedicated neurosurgical pharmacy services were retrospectively reviewed. The clinical pharmacist was responsible for monitoring and evaluating all adult patients on the service and rounding with the team 6 days a week.

RESULTS

A total of 2156 patients were admitted during the study period. No significant differences were noted among severity of illness scores between the 2 groups. During this time, 11 250 interventions were recorded by the pharmacist. The average pharmacy and intravenous therapy cost per patient between the pre- and postimplementation groups decreased from $4833 to $3239, resulting in a total savings of $1,718,260 over the duration of the study period. The average hospital stay decreased from 8.56 to 7.24 days (P = 0.003). Early hospital mortality also decreased from 3.34% to 1.95% (P = 0.06). For those patients who were discharged from the hospital, there was a significant decrease in readmission rates between the 2 groups (P < 0.05)

CONCLUSION

Having a dedicated clinical pharmacist with critical care training rounding routinely with a neurosurgical team significantly reduced hospital stay, readmission rates, and pharmacy costs. Clinical pharmacists can have a significant effect on clinical and economic measures in the intensive care unit, and their participation on a multidisciplinary critical care team should be a standard of care.

A compact VEGF signature associated with distant metastases and poor outcomes

BACKGROUND

Tumor metastases pose the greatest threat to a patient's survival, and thus, understanding the biology of disseminated cancer cells is critical for developing effective therapies.

METHODS

Microarrays and immunohistochemistry were used to analyze primary breast tumors, regional (lymph node) metastases, and distant metastases in order to identify biological features associated with distant metastases.

RESULTS

When compared with each other, primary tumors and regional metastases showed statistically indistinguishable gene expression patterns. Supervised analyses comparing patients with distant metastases versus primary tumors or regional metastases showed that the distant metastases were distinct and distinguished by the lack of expression of fibroblast/mesenchymal genes, and by the high expression of a 13-gene profile (that is, the 'vascular endothelial growth factor (VEGF) profile') that included VEGF, ANGPTL4, ADM and the monocarboxylic acid transporter SLC16A3. At least 8 out of 13 of these genes contained HIF1alpha binding sites, many are known to be HIF1alpha-regulated, and expression of the VEGF profile correlated with HIF1alpha IHC positivity. The VEGF profile also showed prognostic significance on tests of sets of patients with breast and lung cancer and glioblastomas, and was an independent predictor of outcomes in primary breast cancers when tested in models that contained other prognostic gene expression profiles and clinical variables.

CONCLUSION

These data identify a compact in vivo hypoxia signature that tends to be present in distant metastasis samples, and which portends a poor outcome in multiple tumor types.This signature suggests that the response to hypoxia includes the ability to promote new blood and lymphatic vessel formation, and that the dual targeting of multiple cell types and pathways will be needed to prevent metastatic spread.

Guidelines for the initial management of metastatic brain tumors: role of surgery, radiosurgery, and radiation therapy

Brain metastases are an increasingly important determinant of survival and quality of life in patients with cancer. Current approaches to the management of brain metastases are driven by prognostic factors, including the Karnofsky Performance Status, tumor histology, number of metastases, patient age, and status of systemic disease. Most brain metastases are treated with radiosurgery, computer-assisted surgery, or whole brain radiation therapy. Remarkable advances in computer-assisted neuronavigation have made neurosurgical removal of metastases safer, even in eloquent areas of the brain. Computerization also enhances the efficacy and safety of conformal radiosurgery planning using various modern stereotactic radiosurgery (SRS) technologies, including newer frameless-based systems. Controversial issues include whether to defer whole brain radiotherapy (WBRT) in patients undergoing SRS or image-guided surgery and when to use SRS "boost" in a patient undergoing WBRT. The determination of how best to apply these treatments for individual patients cannot be standardized to a single paradigm, but data from well-controlled studies help physicians make informed decisions about the benefits and risks of each approach.

PREDICTORS AND INCIDENCE OF CENTRAL DIABETES INSIPIDUS AFTER ENDOSCOPIC PITUITARY SURGERY

OBJECTIVE

With the advent of minimally invasive endoscopic pituitary surgery, there has been concern that the technique may be associated with higher rates of complications such as diabetes insipidus (DI) than traditional approaches, particularly early in a center's experience. We report the incidence and predictors of diabetes insipidus in patients after endoscopic transnasal resection (minimally invasive pituitary surgery) of pituitary lesions.

METHODS

Data were collected from hospital and clinic records on the first 119 consecutive patients undergoing endoscopic pituitary surgery at our center.

RESULTS

The rate of postoperative diabetes insipidus is low in patients undergoing minimally invasive pituitary surgery (permanent, 2.7%; transient, 13.6%). Factors associated with development of DI after minimally invasive pituitary surgery include Rathke's cleft cyst histology, intraoperative cerebrospinal fluid leak, and previous nonendoscopic lesion resection. Elevated serum sodium (&gt;145 mmol/L) within the first 5 days postoperatively has a high sensitivity (87.5%), specificity (83.5%), and negative predictive value (99.5%) for permanent postoperative DI development.

CONCLUSION

Transitioning from microscopic to endoscopic pituitary surgery can be achieved with a low incidence of DI. An elevated serum sodium level in the first 5 postoperative days using standard monitoring can predict the chance of developing permanent DI. Patients having no elevated serum sodium measurements, defined as &gt;145 mmol/L, in the first 5 days postoperatively will rarely, if ever, develop permanent DI, thereby validating short postoperative inpatient stays with minimal risk of readmission for DI management. Those with a single serum sodium measurement greater than 145 mmol/L have a 15% risk of developing permanent DI.

Blood vessel morphologic changes depicted with MR angiography during treatment of brain metastases: a feasibility study

PURPOSE

To prospectively determine if magnetic resonance (MR) angiography can depict intracranial vascular morphologic changes during treatment of brain metastases from breast cancer and if serial quantitative vessel tortuosity measurements can be used to predict tumor treatment response sooner than traditional methods.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. Twenty-two women aged 31-61 years underwent brain MR angiography prior to and 2 months after initiation of lapatinib therapy for brain metastases from breast cancer. Vessels were extracted from MR angiograms with a computer program. Changes in vessel number, radius, and tortuosity were calculated mathematically, normalized with values obtained in 34 healthy control subjects (19 women, 15 men; age range, 19-72 years), and compared with subsequent assessments of tumor volume and clinical course.

RESULTS

All patients exhibited abnormal vessel tortuosity at baseline. Nineteen (86%) patients did not exhibit improvement in vessel tortuosity at 2-month follow-up, and all patients demonstrated tumor growth at 4-month follow-up. Vessel tortuosity measurements enabled us to correctly predict treatment failure 1-2 months earlier than did traditional methods. Three (14%) patients had quantitative improvement in vessel tortuosity at 2-month follow-up, with drop out of small abnormal vessels and straightening of large vessels. Each of the two patients for whom further follow-up data were available responded to treatment for more than 6 months.

CONCLUSION

Study results established the feasibility of using MR angiography to quantify vessel shape changes during therapy. Although further research is required, results suggest that changes in vessel tortuosity might enable early prediction of tumor treatment response.