Convection enhanced delivery of macromolecules for brain tumors

The blood brain barrier (BBB) poses a significant challenge for drug delivery of macromolecules into the brain. Convection-enhanced delivery (CED) circumvents the BBB through direct intracerebral infusion using a hydrostatic pressure gradient to transfer therapeutic compounds. The efficacy of CED is dependent on the distribution of the therapeutic agent to the targeted region. Here we present a review of convection enhanced delivery of macromolecules, emphasizing the role of tracers in enabling effective delivery anddiscuss current challenges in the field.

Outcome and prognostic factors in adult cerebellar glioblastoma

Cerebellar glioblastoma multiforme (GBM) occurs rarely in adults, accounting for 0.4-3.4% of all GBM. Current studies have all involved small patient numbers, limiting the clear identification of prognostic factors. Additionally, while few studies have compared cerebellar GBM to their supratentorial counterparts, there is conflicting data regarding their relative prognosis. To better characterize outcome and identify patient and treatment factors which affect survival, the authors analyzed cases of adult cerebellar GBM from the Surveillance, Epidemiology, and End Results database. A total of 247 adult patients with cerebellar GBM were identified, accounting for 0.67% of all adult GBM. Patients with cerebellar GBM were significantly younger than those with supratentorial tumors (56.6 versus 61.8 years, p < 0.0001), but a larger percentage of patients with supratentorial GBM were Caucasian (91.7% versus 85.0%, p < 0.0001). Overall median survival did not differ between those with cerebellar and supratentorial GBM (7 versus 8 months, p = 0.24), with similar rates of long-term (greater than 2 years) survival (13.4% versus 10.6%, p = 0.21). Multivariate analysis revealed age greater than 40 years (hazard ratio [HR]: 2.20; 95% confidence interval [CI]: 1.47-3.28; p = 0.0001) to be associated with worse patient survival, while the use of radiotherapy (HR: 0.33; 95% CI: 0.24-0.47; p < 0.0001) and surgical resection (HR: 0.66; 95% CI: 0.45-0.96; p = 0.028) were seen to be independent favorable prognostic factors. In conclusion, patients with cerebellar GBM have an overall poor prognosis, with radiotherapy and surgical resection significantly improving survival. As with supratentorial GBM, older age is a poor prognostic factor. The lack of differences between supratentorial and cerebellar GBM with respect to overall survival and prognostic factors suggests these tumors to be biologically similar.

Phase II trial for patients with newly diagnosed glioblastoma (GBM) treated with carmustine wafers followed by concurrent radiation therapy (RT), temozolomide (TMZ), and bevacizumab (BV), then followed by TMZ and BV post-RT

e13015^

Background: Standard treatment for GBM includes RT and TMZ, followed by six cycles of TMZ, for a median overall survival (OS) and progression-free survival (PFS) of 14.6 and 6.9 months, respectively. BV is FDA approved for recurrent GBM and carmustine wafers are approved for newly diagnosed and recurrent GBM. We evaluated the safety and efficacy of carmustine wafers insertion followed by concurrent RT, TMZ and BV, followed by TMZ and BV for newly diagnosed GBM patients. Methods: Treatment consisted of: Part A- carmustine wafers insertion at resection followed by RT and TMZ at 75 mg/m2/day. BV at 10 mg/kg every two weeks started at least 28 days post-operatively. Part B- Patients received 12 cycles of TMZ (200 mg/m2on days 1-5 of a 28-day cycle) and BV every two weeks (day 1 and 15). Results: Forty one patients of a planned accrual of 72 were enrolled. The study was closed early due to six grade 4-5 toxicities related to study intervention, which met the safety criteria to discontinue the trial. Three patients had grade 4 cerebral edema and one each had grade 4 fatigue, wound infection and meningitis. Median age was 56 years (range, 27-77 years) and 28 patients were men. Of 41 patients, 36 completed part A and 31 started part B. Eleven patients are still on study and 4 have completed part B. Twenty six patients are off study due to progression (n = 16), adverse events (n = 8) and consent withdrawal (n = 2). At a median follow-up of 12.6 months (95% CI: 10.8-15.6 months) the median PFS is 11.3 months (95% CI: 9.2-12.9 months) and the median OS is 16.1 months (95% CI: 15.8 months- ∞). Grade 3-5 toxicities so far include: thrombocytopenia (grade 3, n = 2; grade 4, n = 2), stroke (grade 3, n = 1; grade 5, n = 1), infection (grade 3, n = 2), meningitis (grade 3, n = 1; grade 4, n=1), venous thromboembolic events (grade 3, n = 5), cerebral edema (grade 4, n = 3), fatigue (grade 4, n = 1), enterocolitis (grade 3, n = 1), and wound infection (grade 3, n = 2; grade 4, n = 1). Conclusions: For the patients who did well post carmustine wafers insertion, the treatment was tolerable and median PFS and OS has improved. Updated survival and toxicity results will be presented. Clinical trial information: NT01186406.

Dose-finding and safety study of an oncolytic polio/rhinovirus recombinant against recurrent glioblastoma

2094

Background: Current therapies for glioblastoma are limited by ineffective delivery beyond the blood-brain barrier, limited diffusion of macromolecules, and lack of tumor specificity. Sustained direct intracerebral infusion at slow flow rates [convection-enhanced delivery (CED)] can overcome delivery barriers. PVSRIPO is the live attenuated, oral (SABIN) serotype 1 poliovirus vaccine containing a heterologous internal ribosomal entry site stemming from human rhinovirus type 2. PVSRIPO recognizes nectin-like molecule-5, an oncofetal cell adhesion molecule and tumor antigen widely expressed ectopically in malignancy. We report the results of an ongoing phase I study evaluating PVSRIPO when delivered by CED. Methods: Eligible on study are adult patients with: 1-5 cm of measurable supratentorial recurrent glioblastoma ≥1cm away from the ventricles; ≥4 weeks after chemotherapy, bevacizumab or study drug; adequate organ function; KPS ≥70%; and positive anti-poliovirus titer. PVSRIPO is delivered intratumorally by CED over 6.5 hours. PVSRIPO dose escalation is accomplished by increasing agent concentration, allowing flow-rate and infusion volume to remain constant. Two-step continual reassessment method is used for dose escalation, with one patient each treated on dose levels 1-4, and a possibility of up to 13 patients on dose level 5. Results: Thus far, a total of five patients have been treated on study. No related or unrelated grade 3 or higher adverse events have been observed. Grade 1 adverse events possibly related to the study drug or procedure include one each of fever, cough, nasal congestion, vomiting, headache, hemiparesis, and lethargy. Grade 2 adverse events include one each of diarrhea and seizure. Patient #1 had failed bevacizumab prior to enrollment and remains disease free more than 9 months post PVSRIPO. Two more patients are disease free 8+ and 2+ months post treatment, respectively. One patient had pathology confirmed disease recurrence two months post treatment and one patient came off study due to clinical decline four months post treatment. Conclusions: Infusion of PVSRIPO via CED is safe thus far and encouraging efficacy results are observed. Updated results will be presented. Clinical trial information: NCT 01491893.

Low-grade astrocytomas: the prognostic value of fibrillary, gemistocytic, and protoplasmic tumor histology

OBJECT

Low-grade astrocytomas are slow-growing, infiltrative gliomas that over time may progress into more malignant tumors. Various factors have been shown to affect the time to progression and overall survival including age, performance status, tumor size, and the extent of resection. However, more recently it has been suggested that histological subtypes (fibrillary, protoplasmic, and gemistocytic) may impact patient outcome. In this study the authors have performed a large comparative population-based analysis to examine the characteristics and survival of patients with the various subtypes of WHO Grade II astrocytomas.

METHODS

Patients diagnosed with fibrillary, protoplasmic, and gemistocytic astrocytomas were identified through the Surveillance, Epidemiology, and End Results (SEER) database. The chi-square test and Student t-test were used to evaluate differences in patient and treatment characteristics between astrocytoma subtypes. Kaplan-Meier analysis was used to assess overall survival, and the log-rank test was used to evaluate the differences between survival curves. Univariate and multivariate analyses were also performed to determine the effect of various patient, tumor, and treatment variables on overall survival.

RESULTS

A total of 500 cases were included in the analysis, consisting of 326 fibrillary (65.2%), 29 protoplasmic (5.8%), and 145 gemistocytic (29%) variants. Gemistocytic astrocytomas presented at a significantly older age than the fibrillary variant (46.8 vs 37.7 years, p < 0.0001), with protoplasmic and fibrillary subtypes having a similar age. Although protoplasmic and fibrillary variants underwent radiotherapy at similar rates, gemistocytic tumors more frequently received radiotherapy (p = 0.0001). Univariate analysis revealed older age, larger tumor size, and the use of radiotherapy to be poor prognostic factors, with resection being associated with improved survival. The gemistocytic subtype (hazard ratio [HR] 1.62 [95% CI 1.27-2.07], p = 0.0001) also resulted in significantly worse survival than fibrillary tumors. Bivariate analyses demonstrated that older age, the use of radiotherapy, and resection significantly influenced median survival. Tumor subtype also affected median survival; patients who harbored gemistocytic tumors experienced less than half the median survival of fibrillary and protoplasmic tumors (38 vs 82 months, p = 0.0003). Multivariate analysis revealed increasing age (HR 1.05 [95% CI 1.04-1.05], p < 0.0001), larger tumor size (HR 1.02 [95% CI 1.01-1.03], p = 0.0002), and the use of resection (HR 0.70 [95% CI 0.52-0.94], p = 0.018) to be independent predictors of survival. Examination of tumor subtype revealed that the gemistocytic variant (HR 1.30 [95% CI 0.98-1.74], p = 0.074) was associated with worse patient survival than fibrillary tumors, although this only approached significance. The protoplasmic subtype did not affect overall survival (p = 0.33).

CONCLUSIONS

Gemistocytic tumor histology was associated with worse survival than fibrillary and protoplasmic astrocytomas. As protoplasmic astrocytomas have a survival similar to fibrillary tumors, there may be limited utility to the identification of this rare variant. However, increased attention should be paid to the presence of gemistocytes in low-grade gliomas as this is associated with shorter time to progression, increased malignant transformation, and reduced overall survival.

Long-term Economic Impact of Coiling vs Clipping for Unruptured Intracranial Aneurysms

BACKGROUND:

Treatment of unruptured intracranial aneurysms (UIAs) involves endovascular coiling or aneurysm clipping. While many studies have compared these treatment modalities with respect to various clinical outcomes, few studies have investigated the economic costs associated with each procedure.

OBJECTIVE:

To determine the reoperation rate, postoperative complications, and inpatient and outpatient costs associated with surgical or endovascular treatment of patients with UIAs in the United States.

METHODS:

We utilized the MarketScan database to examine patients who underwent surgical clipping or endovascular coiling procedures for UIAs from 2000 to 2009, comparing reoperation rates, complications, and angiogram and healthcare resource use. Propensity score matching techniques were used to match patients.

RESULTS:

We identified 4,504 patients with surgically treated UIAs, with propensity score matching of 3,436 patients. Reoperation rates were significantly lower in the clipping group compared to the coiling group at 1- (P &lt; .001), 2- (P &lt; .001), and 5 years (P &lt; .001) following the procedure. However, postoperative complications (immediate, 30 and 90 days) were significantly higher in those undergoing surgical clipping. Although hospital length of stay and costs were higher in the clipping group for the index procedure, the number of postoperative angiograms and outpatient services used at 1, 2, and 5 years were significantly higher in the coiling group.

CONCLUSION:

Though surgical clipping resulted in lower reoperation rates, it was associated with higher complication rates and initial costs. However, overall costs at 2 and 5 years were similar to endovascular coiling due to the significantly higher number of follow-up angiograms and outpatient costs in these patients.

Vestibular schwannomas in the modern era: epidemiology, treatment trends, and disparities in management

OBJECT

There are a variety of treatment options for the management of vestibular schwannomas (VSs), including microsurgical resection, radiotherapy, and observation. Although the choice of treatment is dependent on various patient factors, physician bias has been shown to significantly affect treatment choice for VS. In this study the authors describe the current epidemiology of VS and treatment trends in the US in the modern era. They also illustrate patient and tumor characteristics and elucidate their effect on tumor management.

METHODS

Patients diagnosed with VS were identified through the Surveillance, Epidemiology, and End Results database, spanning the years 2004-2009. Age-adjusted incidence rates were calculated and adjusted using the 2000 US standard population. The chi-square and Student t-tests were used to evaluate differences between patient and tumor characteristics. Multivariate logistic regression was performed to determine the effects of various patient and tumor characteristics on the choice of tumor treatment.

RESULTS

A total of 6225 patients with VSs treated between 2004 and 2009 were identified. The overall incidence rate was 1.2 per 100,000 population per year. The median age of patients with VS was 55 years, with the majority of patients being Caucasian (83.16%). Of all patients, 3053 (49.04%) received surgery only, with 1466 (23.55%) receiving radiotherapy alone. Both surgery and radiation were only used in 123 patients (1.98%), with 1504 patients not undergoing any treatment (24.16%). Increasing age correlated with decreased use of surgery (OR 0.95, 95% CI 0.95-0.96; p<0.0001), whereas increasing tumor size was associated with the increased use of surgery (OR 1.04, 95% CI 1.04-1.05; p<0.0001). Older age was associated with an increased likelihood of conservative management (OR 1.04, 95% CI 1.04-1.05; p<0.0001). Racial disparities were also seen, with African American patients being significantly less likely to receive surgical treatment compared with Caucasians (OR 0.50, 95% CI 0.35-0.70; p<0.0001), despite having larger tumors at diagnosis.

CONCLUSIONS

The incidence of vestibular schwannomas in the US is 1.2 per 100,000 population per year. Although many studies have demonstrated improved outcomes with the use of radiotherapy for small- to medium-sized VSs, surgery is still the most commonly used treatment modality for these tumors. Racial disparities also exist in the treatment of VSs, with African American patients being half as likely to receive surgery and nearly twice as likely to have their VSs managed conservatively despite presenting with larger tumors. Further studies are needed to elucidate the reasons for treatment disparities and investigate the nationwide trend of resection for the treatment of small VSs.

Thickness of subcutaneous fat as a risk factor for infection in cervical spine fusion surgery

BACKGROUND

Surgical site infections increase the incidence of morbidity and mortality as well as health-care expenses. The cost of care increases threefold to fourfold as a consequence of surgical site infection after spinal surgery. The aim of the present study was to determine the role of subcutaneous fat thickness in the development of surgical site infection following cervical spine fusion surgery.

METHODS

We performed a retrospective review of a consecutive cohort of 213 adult patients who underwent posterior cervical spine fusion between 2006 and 2008 at Duke University Medical Center. The horizontal distance from the lamina to the skin surface at the C5 level and the thickness of subcutaneous fat were measured, and the ratio of the fat thickness to the total distance at the surgical site was determined. Previously identified risk factors for the development of surgical site infection were also recorded.

RESULTS

Twenty-two of the 213 patients developed a postoperative infection. Obesity (body mass index ≥ 30 kg/m2) was not a significant risk factor for surgical site infection; the body mass index (and 95% confidence interval) was 29.4 ± 1.2 kg/m2 in the patients who developed a surgical site infection compared with 28.9 ± 0.94 kg/m2 in the patients without an infection. However, the thickness of subcutaneous fat and the ratio of the fat thickness to the lamina-to-skin distance were both significant risk factors for infection. The thickness of subcutaneous fat was 27.0 ± 2.5 mm in the patients who developed a surgical site infection group compared with 21.4 ± 0.88 mm in the patients without an infection (p = 0.042). The ratio of fat thickness to total thickness was 0.42 ± 0.019 in the patients who developed a surgical site infection compared with 0.35 ± 0.01 in the patients without an infection (p = 0.020). Multivariate analysis revealed this ratio to be an independent risk factor for developing a postoperative infection (odds ratio, 3.18; 95% confidence interval, 1.02 to 9.97).

CONCLUSIONS

The study demonstrated that the thickness of subcutaneous fat at the surgical site is a factor in the development of surgical site infection following cervical spine fusion and deserves assessment in the preoperative evaluation.

Thrombin and hemin as central factors in the mechanisms of intracerebral hemorrhage-induced secondary brain injury and as potential targets for intervention

Intracerebral hemorrhage (ICH) is a subtype of stoke that may cause significant morbidity and mortality. Brain injury due to ICH initially occurs within the first few hours as a result of mass effect due to hematoma formation. However, there is increasing interest in the mechanisms of secondary brain injury as many patients continue to deteriorate clinically despite no signs of rehemorrhage or hematoma expansion. This continued insult after primary hemorrhage is believed to be mediated by the cytotoxic, excitotoxic, oxidative, and inflammatory effects of intraparenchymal blood. The main factors responsible for this injury are thrombin and erythrocyte contents such as hemoglobin. Therapies including thrombin inhibitors, N-methyl-D-aspartate antagonists, chelators to bind free iron, and antiinflammatory drugs are currently under investigation for reducing this secondary brain injury. This review will discuss the molecular mechanisms of brain injury as a result of intraparenchymal blood, potential targets for therapeutic intervention, and treatment strategies currently in development.

Surgical management of nonvascular lesions around the oculomotor nerve

OBJECTIVE

Schwannomas originating from the oculomotor nerve are extremely rare. We report our experience in the management of oculomotor schwannomas and other lesions mimicking them, and discuss operative strategy for these rare tumors emphasizing oculomotor nerve preservation.

METHODS

The clinical records of our patients and all those reported in the literature focusing on oculomotor schwannomas were reviewed and analyzed. The clinical presentations, operative approaches, complications, and results were studied.

RESULTS

Between 1983 and 2010, six patients with primary oculomotor nerve lesions were treated. Three of them had schwannomas. Two others had pathologies that mimicked an oculomotor schwannoma and one was suspected as schwannoma. In the literature there were 55 previous cases of oculomotor schwannomas reported (surgical treated, 41 cases; observed, 9; gamma knife surgery treated, 2; autopsy, 3). Patients presented most commonly with diplopia, followed by headache and ptosis as initial symptoms. Out of 55 patients including the present 3 cases (3 autopsy cases were excluded), 30 patients (54.5%) finally developed oculomotor nerve palsy. Fifteen of 44 patients (34.1%) who underwent surgery developed persistent postoperative oculomotor palsy. Among them, 6 patients developed total palsy after surgery. Five of 12 patients (41.7%) who did not undergo surgery also developed oculomotor palsy. Oculomotor schwannomas most often grow its cisternal segment (48.3%) followed by intracavernous (39.6%) and cisternocavernous segments (12.1%).

CONCLUSION

The microsurgical resection of oculomotor schwannomas carries a risk of worsening preoperative oculomotor nerve function; however, this is often transient. Considerable technical training and microanatomical knowledge of the region is required to optimize outcome.

Evaluation of variation in the course of the facial nerve, nerve adhesion to tumors, and postoperative facial palsy in acoustic neuroma

Objective To investigate the variation in the course of the facial nerve (FN) in patients undergoing acoustic neuroma (AN) surgery, its adhesion to tumors, and the relationship between such adhesions and postoperative facial palsy. Methods The subjects were 356 patients who underwent AN surgery in whom the course of the FN could be confirmed. Patients were classified into six groups: ventro-central surface of the tumor (VCe), ventro-rostral (VR), ventro-caudal (VCa), rostral (R), caudal (C), and dorsal (D). Results The FN course was VCe in 185 cases, VR in 137, VCa in 19, R in 10, C in 4, and D in one. For tumors < 1.5 cm, VCe was most common. For tumors ≥ 1.5 cm, the proportion of VR increased. No significant difference was observed between the course patterns of the FN in terms of postoperative FN function, but for tumors > 3.0 cm, there was an increasing tendency for the FN to adhere strongly to the tumor capsule, and postoperative facial palsy was more severe in patients with stronger adhesions. Conclusions The VCe pattern was most common for small tumors. Strong or less strong adhesion to the tumor capsule was most strongly associated with postoperative FN palsy.

Calcifying pseudoneoplasms of the skull base presenting with cranial neuropathies: case report and literature review

Objectives We report our institutional experience with calcifying pseudoneoplasms of the skull base that presented with cranial neuropathies. These lesions are also known as fibro-osseous lesions, cerebral calculi, or brain stones.

Results One patient presented with facial numbness and retro-orbital pain secondary to compression of the maxillary branch of the trigeminal nerve at the anterior portion of the infratemporal fossa. The other patient presented with occipital headaches and hypoglossal nerve palsy. This patient was found to have a calcified lesion in the posterior fossa, which eroded the left occipital condyle.

Conclusion Calcifying pseudoneoplasms are benign, slow-growing masses that are apparently cured by gross total resection. Even with incomplete tumor resection, the prognosis is considered to be favorable. We advocate a minimally invasive surgical resection of such tumors involving the cranial nerves.

Frequent ATRX, CIC, FUBP1 and IDH1 mutations refine the classification of malignant gliomas

Mutations in the critical chromatin modifier ATRX and mutations in CIC and FUBP1, which are potent regulators of cell growth, have been discovered in specific subtypes of gliomas, the most common type of primary malignant brain tumors. However, the frequency of these mutations in many subtypes of gliomas, and their association with clinical features of the patients, is poorly understood. Here we analyzed these loci in 363 brain tumors. ATRX is frequently mutated in grade II-III astrocytomas (71%), oligoastrocytomas (68%), and secondary glioblastomas (57%), and ATRX mutations are associated with IDH1 mutations and with an alternative lengthening of telomeres phenotype. CIC and FUBP1 mutations occurred frequently in oligodendrogliomas (46% and 24%, respectively) but rarely in astrocytomas or oligoastrocytomas ( more than 10%). This analysis allowed us to define two highly recurrent genetic signatures in gliomas: IDH1/ATRX (I-A) and IDH1/CIC/FUBP1 (I-CF). Patients with I-CF gliomas had a significantly longer median overall survival (96 months) than patients with I-A gliomas (51 months) and patients with gliomas that did not harbor either signature (13 months). The genetic signatures distinguished clinically distinct groups of oligoastrocytoma patients, which usually present a diagnostic challenge, and were associated with differences in clinical outcome even among individual tumor types. In addition to providing new clues about the genetic alterations underlying gliomas, the results have immediate clinical implications, providing a tripartite genetic signature that can serve as a useful adjunct to conventional glioma classification that may aid in prognosis, treatment selection, and therapeutic trial design.

The addition of bevacizumab to temozolomide and radiation therapy followed by bevacizumab, temozolomide, and oral topotecan for newly diagnosed glioblastoma multiforme (GBM)

2090^

Background: The prognosis for newly-diagnosed GBM is dismal. The addition of temozolomide to radiation therapy improved the median overall survival (OS) to 14.6 months (mos). GBM’s have the highest levels of vascular endothelial growth factor (VEGF). Hypoxia inducing factor-1 alpha (HIF-1 alpha) is an important regulator of VEGF, and topotecan may inhibit HIF-1 alpha. Methods: We performed a phase II trial in newly diagnosed GBM by adding bevacizumab and topotecan to standard therapy. 80 newly diagnosed GBM patients were enrolled between January 2010 and January 2011. Patients received standard radiation therapy and temozolomide. Bevacizumab at 10 mg/kg every 14 days was added a minimum of 4 weeks post-op. Two weeks after radiation therapy was completed, 12 monthly cycles of temozolomide at 150 mg/m2 /d days 1-5, oral topotecan at 1.5 mg/m2 for patients not on an enzyme inducing anti-epileptic drug (EIAED) and 2.0 mg/m2 for patients on an EIAED days 2-6, and bevacizumab at 10 mg/kg on days 1 and 15. Results: The addition of bevacizumab to standard radiation therapy and daily temozolomide was safe. Of the 80 patients, 76 completed radiation therapy. Four patients did not complete radiation, two with clinical decline, one each with a bone flap infection, and a pulmonary embolus. Fifteen patients came off study for toxicity, five with recurrent grade IV thrombocytopenia, three with grade III fatigue, two each with grade 2 CNS hemorrhage, and wound dehiscence requiring surgery and one each with GI perforation, pulmonary embolism and an aortic thrombus. Of the 80 patients, 56 have progressed and 37 have died. The median progression-free survival (PFS) and OS are 11.1 mos (95% CI: 9.4-13.6) and 17.2 mos (95% CI: 15.2) at a median follow-up of 18.4 months. The two year OS is 45.3%. Conclusions: The addition of bevacizumab to temozolomide and radiation followed by temozolomide, bevacizumab and oral topotecan is tolerable. The median PFS and OS are encouraging. The randomized phase III trials with bevacizumab for newly diagnosed GBM patients are essential.

Phase II study of bevacizumab plus irinotecan and carboplatin for recurrent WHO grade 3 malignant gliomas with no prior bevacizumab failure

2095^

Background: No standard treatment exists for recurrent WHO grade 3 malignant glioma patients. Bevacizumab (BV) with irinotecan has significant anti-tumor activity for recurrent glioblastoma. Carboplatin has anti-glioma activity and can potentiate the cytotoxicity of irinotecan. We evaluated the progression-free survival (PFS) of BV in combination to irinotecan and carboplatin in recurrent WHO grade 3 malignant gliomas, as well as its safety. Methods: Adult patients with measurable recurrent WHO grade 3 malignant glioma, ≥12 weeks after radiation therapy, ≥4 weeks after chemotherapy, with adequate organ function, KPS ≥70%, no prior failure or grade ≥3 toxicity to the agents, and no contraindications to BV were eligible for study. Patients received BV at 10 mg/kg with irinotecan on days 1 and 15 of a 28-day cycle. The dose of irinotecan was 125 mg/m2 for patients not on enzyme inducing anti-epileptics (EIAEDs) and 340 mg/m2 for patients on EIAEDs. All patients received carboplatin at an AUC of 4 on day 1 of each cycle. MRIs were obtained every 8 weeks. Results: As planned, 39 WHO grade III malignant glioma patients were enrolled on study. Median age was 47 (range, 26-71). At a median follow up of 14 months, the 6-month PFS is 69% and the median PFS is 11 months. A median of 8 cycles were given. Seven patients completed the planned course of treatment (12 cycles) with hypometabolic PET scan and nine patients remain on study. Fifteen patients came off study due to disease progression and eight due to toxicity. As of 1/25/2012, 22 patients are still alive and 17 have died. Grade 3-4 toxicities included: neutropenia (grade 3, n=12; grade 4, n= 1), thrombocytopenia (grade 3, n=6; grade 4, n=4), nausea (grade 3, n=7), diarrhea (grade 3, n=2), deep venous thrombosis (grade 3, n=2), febrile neutropenia (grade 3, n=1; grade 4, n=1), fatigue (grade 3, n=8; grade 4, n=1), cerebral infarction (grade 4, n=3), intracranial hemorrhage (grade 4, n=1), posterior reversible encephalopathy syndrome (grade 3, n=1). Conclusions: The combination of bevacizumab, irinotecan and carboplatin for WHO grade 3 malignant glioma patients is effective and with no more than expected toxicity.

Safety and efficacy of the addition of bevacizumab to temozolomide and radiation therapy followed by bevacizumab, temozolomide, and irinotecan for newly diagnosed glioblastoma multiforme

2094^

Background: Glioblastoma (GBM) has a very poor prognosis, and the majority of patients die within 2 years of diagnosis. GBMs have high concentrations of vascular endothelial growth factor (VEGF), and the more VEGF, the worse the prognosis. Bevacizumab is a humanized antibody to VEGF and is active in recurrent GBMs. The study aims to improve the survival of newly diagnosed GBM patients by incorporating an anti-angiogenic agent with radiation and temozolomide, and adding a topoisomerase I inhibitor, and an anti-angiogenic agent to temozolomide post-radiation therapy. Methods: Patients received standard radiation and temozolomide at 75 mg/m2/day, with bevacizumab at 10 mg/kg every 14 days beginning a minimum of 28 days post-operatively. Following the completion of radiation therapy, patients received 6-12 cycles of bevacizumab, temozolomide and irinotecan. Each cycle was 28 days. Bevacizumab was given at a dose of 10 mg/kg days 1 and 15, temozolomide 200 mg/m2 days 1-5 and irinotecan on days 1 and 15 at 125 mg/m2 for patients not on an enzyme inducing anti-epileptic (EIAED) and 340 mg/m2 for patients on an EIAED. The statistical design was a goal of 60% overall survival at 16 months. Results: 125 patients were enrolled between 8/07 and 3/09. All the patients have completed therapy. Nine patients had thromboembolic complications (DVT or PE). Two patients had wound dehiscence, one bowel perforation, one secondary AML and two pneumocystis carinii pneumonias (PCP). Seventeen had grade 4 hematologic toxicity requiring dose decrements. There were 4 toxic deaths, one each with a myocardial infarction PCP, PE and sepsis. At a median follow-up of 40 mos, the median overall survival was 20.9 mos, the median progression-free survival was 13.8 mos and the 2-year overall survival was 42.4%. Conclusions: Adding bevacizumab to temozolomide and radiation therapy followed by bevacizumab, temozolomide with irinotecan is tolerable and efficacious.

Microsurgical management of hypoglossal schwannomas over 3 decades: a modified grading scale to guide surgical approach

BACKGROUND

Schwannomas originating from the hypoglossal nerve are extremely rare. Microsurgical resection with the goal for cure has traditionally been associated with a high risk of postoperative deficits.

OBJECTIVE

To summarize our clinical experience using tailored cranial base approaches for these formidable lesions.

METHODS

The clinical records of 13 patients were retrospectively reviewed. In addition, all reported patients in the literature were reviewed. The extreme lateral infrajugular transcondylar-transtubercular exposure approach was used in all of our patients. Based on our experience and literature analysis, we propose the following modified grading scale to facilitate surgical planning: type A, intradural tumors; type B, dumbbell-shaped tumors; type C, extracranial tumors; and type D, peripheral tumors.

RESULTS

All 13 patients underwent total, near-total, or subtotal tumor resection. Eight patients were men, 5 were women (mean age, 41.7 years). Sural nerve graft reconstruction for the hypoglossal nerve was performed in 4 patients. Three of the 4 patients in whom nerve reconstruction was performed regained satisfactory movement of their tongue. In the review of the literature, the mean patient age was 45.8 years. Patients presented with tongue atrophy (91.6%), headache (60.9%), and dysphagia (31.8%). The tumors were categorized as type A in 31.7% of these patients, type B in 38.6%, type C in 6.2%, and type D in 23.4%.

CONCLUSION

The extreme lateral infrajugular transcondylar-transtubercular exposure approach, which is a modification of the extreme lateral suboccipital approach, provides sufficient exposure for most intracranial dumbbell-shaped hypoglossal schwannomas. Hypoglossal nerve reconstruction using a sural nerve graft improves tongue atrophy and movement for patients with resected nerves.

A pilot study of IL-2Rα blockade during lymphopenia depletes regulatory T-cells and correlates with enhanced immunity in patients with glioblastoma

BACKGROUND

Preclinical studies in mice have demonstrated that the prophylactic depletion of immunosuppressive regulatory T-cells (T(Regs)) through targeting the high affinity interleukin-2 (IL-2) receptor (IL-2Rα/CD25) can enhance anti-tumor immunotherapy. However, therapeutic approaches are complicated by the inadvertent inhibition of IL-2Rα expressing anti-tumor effector T-cells.

OBJECTIVE

To determine if changes in the cytokine milieu during lymphopenia may engender differential signaling requirements that would enable unarmed anti-IL-2Rα monoclonal antibody (MAbs) to selectively deplete T(Regs) while permitting vaccine-stimulated immune responses.

METHODOLOGY

A randomized placebo-controlled pilot study was undertaken to examine the ability of the anti-IL-2Rα MAb daclizumab, given at the time of epidermal growth factor receptor variant III (EGFRvIII) targeted peptide vaccination, to safely and selectively deplete T(Regs) in patients with glioblastoma (GBM) treated with lymphodepleting temozolomide (TMZ).

RESULTS AND CONCLUSIONS

Daclizumab treatment (n = 3) was well-tolerated with no symptoms of autoimmune toxicity and resulted in a significant reduction in the frequency of circulating CD4+Foxp3+ TRegs in comparison to saline controls (n = 3)( p = 0.0464). A significant (p<0.0001) inverse correlation between the frequency of TRegs and the level of EGFRvIII specific humoral responses suggests the depletion of TRegs may be linked to increased vaccine-stimulated humoral immunity. These data suggest this approach deserves further study.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00626015.

Tentorial detachment technique in the combined petrosal approach for petroclival meningiomas

OBJECT

The combined petrosal approach is a suitable technique for the resection of medium-to-large petroclival meningiomas (PCMs). Multiple technical modifications have been reported to increase the surgical corridor, including the method of dural and tentorial opening. The authors describe their method of dural opening and tentorial resection, and detail the microanatomy related to their technique to clarify pitfalls and effects.

METHODS

The relationship of temporal bridging veins and cranial nerves (CNs) around the tentorial resection area was examined during the combined petrosal approach in 20 cadaveric specimens. The authors also reviewed their 23 consecutive clinical cases treated using this technique between 2002 and 2010, focusing on the effects and risks of the procedure.

RESULTS

In the authors' method, the tentorial resection extends from 5 to 10 mm anterior to the junction of the sigmoid sinus and the superior petrosal sinus ("sinodural point") to the trigeminal fibrous ring and the dural sleeve of CN IV. Temporal bridging veins enter the transverse sinus no more than 5 mm anterior to the sinodural point. The CN IV should be freed from its tentorial dural sleeve while avoiding disruption of the posterior cavernous sinus. The clinical data demonstrate a total resection rate of 78.3%, intraoperative estimated blood loss < 400 ml at a rate of 80.9%, and a venous congestion rate of 0%.

CONCLUSIONS

Understanding the anatomical relationship between the tentorium and temporal bridging veins and CNs IV-VI allows neurosurgeons the ability to develop a combined petrosal approach to PCMs that will effectively supply a wide operative corridor after resecting the tentorium, while significantly devascularizing tumors.

Colocalization of gadolinium-diethylene triamine pentaacetic acid with high-molecular-weight molecules after intracerebral convection-enhanced delivery in humans

BACKGROUND

Convection-enhanced delivery (CED) permits site-specific therapeutic drug delivery within interstitial spaces at increased dosages through circumvention of the blood-brain barrier. CED is currently limited by suboptimal methodologies for monitoring the delivery of therapeutic agents that would permit technical optimization and enhanced therapeutic efficacy.

OBJECTIVE

To determine whether a readily available small-molecule MRI contrast agent, gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA), could effectively track the distribution of larger therapeutic agents.

METHODS

Gd-DTPA was coinfused with the larger molecular tracer, I-labeled human serum albumin (I-HSA), during CED of an EGFRvIII-specific immunotoxin as part of treatment for a patient with glioblastoma.

RESULTS

Infusion of both tracers was safe in this patient. Analysis of both Gd-DTPA and I-HSA during and after infusion revealed a high degree of anatomical and volumetric overlap.

CONCLUSION

Gd-DTPA may be able to accurately demonstrate the anatomic and volumetric distribution of large molecules used for antitumor therapy with high resolution and in combination with fluid-attenuated inversion recovery (FLAIR) imaging, and provide additional information about leaks into cerebrospinal fluid spaces and resection cavities. Similar studies should be performed in additional patients to validate our findings and help refine the methodologies we used.

Midsubtemporal ridge as a predictor of the lateral loop formed by the maxillary nerve and mandibular nerve: a cadaveric morphological study

BACKGROUND

The lateral loop formed by the maxillary nerve (V2) and the mandibular nerve (V3) consists of a part of the far lateral triangle of the cavernous sinus. Because this triangle becomes a surgical corridor of the preauricular infratemporal fossa approach and a landmark of the extradural approach for the ganglion-type trigeminal schwannomas, identification of the lateral loop has important implications at the early stage of middle cranial base surgery. We realized that a bony ridge usually existed just lateral to the lateral loop.

OBJECTIVE

To nominate midsubtemporal ridge (MSR) as the name for this anatomically unnamed bony ridge and to clarify its features.

METHODS

Using 35 cadaver heads, we measured the shape of the MSR on both sides and the distance between the MSR and the adjacent structures.

RESULTS

The MSR was recognized in 60 of 70 specimens (85.7%). The bony protrusion was 2.9 ± 1.1 mm in height, 6.0 ± 2.1 mm in width, and 9.1 ± 3.2 mm in length. A single peak with anteroposterior length was common in 47 of 60 specimens (78.3%). The MSR was located at the midpoint of the V2 and V3 in 28 specimens (46.7%) and existed 10.7 ± 3.6 mm lateral from the line that bound the foramen rotundum and the foramen ovale.

CONCLUSION

We demonstrate morphological characteristics of the MSR. These data on the MSR will assist the surgeon in identifying the lateral loop as a surgical landmark during middle cranial base surgery.

Calcifying pseudoneoplasm of the cerebellopontine angle: case report

BACKGROUND AND IMPORTANCE

Calcifying pseudoneoplasms are rare tumors of the neuraxis. To our knowledge, this is only the second reported case in the literature of calcifying pseudoneoplasm of the cerebellopontine angle. The etiology and natural history of these neoplasms are not well understood. This case report provides a thorough review of the histology and potential origins of calcifying pseudoneoplasm.

CLINICAL PRESENTATION

A 34-year-old previously healthy man presented with a 6-month history of progressive worsening headaches, fatigue, tinnitus, dizziness, and blurry vision. Neurological examination was notable for tongue deviation, tongue atrophy, and left uvula deviation. Computed tomography (CT) scanning showed a 3.3 × 3.5 cm densely calcified posterior fossa mass appearing to arise from the occipital bone. Magnetic resonance imaging (MRI) revealed a 4.3 × 2.9 × 2.9 cm left posterior fossa enhancing mass with the margin tip from the left occipital condyle. A transcondylar approach was used to resect the lesion. The mass was found to have eroded through the bone into the foramen magnum. Histopathological examination confirmed the diagnosis of calcifying pseudoneoplasm of the cerebellopontine angle.

CONCLUSION

Calcifying pseudoneoplasms should be considered in the differential diagnosis of calcified cerebellopontine angle tumors. Histopathologic diagnosis is extremely important in the characterization of these lesions in order to direct the course of appropriate management. An inaccurate diagnosis of a malignant tumor can result in potentially harmful and unnecessary therapies, as prognosis for these lesions is generally favorable.