Asymptomatic Postoperative Cerebral Venous Sinus Thrombosis After Posterior Fossa Tumor Surgery: Incidence, Risk Factors, and Therapeutic Options.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a known complication of posterior fossa surgery near the sigmoid and transverse sinus. The incidence and treatment of postoperative asymptomatic CVST are controversial. OBJECTIVE: To analyze incidence, risk factors, and management of asymptomatic postoperative CVST after posterior fossa tumor surgery. METHODS: In this retrospective, single-center study, we included all patients who underwent posterior fossa tumor surgery in the semisitting position between January 2013 and December 2020. All patients underwent preoperative and postoperative imaging using MRI with/without additional computed tomography angiography. We analyzed the effect of demographic and surgical data on the incidence of postoperative CVST. Furthermore, therapeutic anticoagulation or conservative treatment for postoperative CVST and the incidence of intracranial hemorrhage were investigated. RESULTS: In total, 266 patients were included. Thirty-three of 266 (12.4%) patients developed postoperative CVST. All patients were asymptomatic. Thirteen of 33 patients received therapeutic anticoagulation, and 20 patients did not. Univariate analysis showed that age ( P = .56), sex ( P = .20), American Society of Anesthesiology status ( P = .13), body mass index ( P = .60), and length of surgery ( P = .176) were not statistically correlated with postoperative CVST. Multivariate analysis revealed that meningioma ( P < .001, odds ratio 11.3, CI 95% 4.1-31.2) and vestibular schwannoma ( P = .013, odds ratio 4.4, CI 95% 1.3-16.3) are risk factors for the development of new postoperative CVST. The use of therapeutic anticoagulation to treat postoperative CVST was associated with a higher rate of intracranial hemorrhage (n = 4, P = .017). CONCLUSION: Tumor entity influences the incidence of postoperative CVST. In clinically asymptomatic patients, careful decision making is necessary whether to initiate therapeutic anticoagulation or not.

Pre-operative dosing of dexamethasone for the management of children with posterior fossa tumours: are we getting it right?

INTRODUCTION: Posterior fossa (PF) tumours are associated with vasogenic oedema causing symptoms of raised intracranial pressure. Preoperatively this is managed with dexamethasone. To minimise steroid related complications, the lowest effective dose should be administered. No neurosurgical guidelines exist for pre-operative dosing of dexamethasone in PF tumours. METHODS: A retrospective review was performed of surgically managed cases for patients under 16 years of age between 2013 and 2018 to ascertain the initial dose of dexamethasone with symptomatic PF tumours. RESULTS: Thirty-six patients were identified of which 30 notes were available. Sixteen were male. Median age was 6 years (range 10 months - 15 years). Twenty-two (73%) were referrals from DGH and 8 (27%) presented to our neurosurgical centre. All patients presented with symptomatic PF tumours including headache (97%), vomiting (93%), gait disturbance (43%), and nystagmus (17%). Four (13%) had papilloedema. Average initial stat dexamethasone dose was 9.15 mg; 0.31 mg/kg (range 1-16.7 mg; 0.05 - 1.77 mg/kg). Stratified according to weight, average dose (and range) was 8.8 mg; 0.94 mg/kg (1-16.6 mg; 0.13 - 1.77 mg/kg) in those weighing <10 kg; 9.7 mg; 0.66 mg/kg (4-16.7 mg; 0.21 - 1.35 mg/kg) in 10-20 kg; 12.3 mg;0.52 mg/kg (8-16.7 mg; 0.27 - 0.73mg/kg) in 20-30 kg and 7.8 mg; 0.17mg/kg (2-16.7 mg; 0.0 - 0.39 mg/kg) in >30 kg up to a maximum of 16.6 mg in any 24h period. These results suggest that dosage was higher in those children weighing less. PPI was used in 24 (80%) of cases. All doses were reduced after review by the neurosurgical team and a PPI added. CONCLUSION: Pre-operative dexamethasone dosing does not always reflect the severity of clinical symptoms for PF tumours. Guidelines are required to correlate clinical symptoms with a suggested suitable dose of dexamethasone to prevent overdose and complications associated with corticosteroid use. We recommend a weight-based regimen as provided by the Food and Drug Administration. The current advice is for 0.02-0.3mg/kg/day in 3-4 divided doses.

Infratentorial immature teratoma of congenital origin can be associated with a 20-year survival outcome: a case report and review of literature.

BACKGROUND: Congenital intracranial tumors are very rare and account for less than 2% of all childhood brain tumors. Teratomas constitute about one third to one half of these, predominantly located midline in the supratentorial region. Posterior fossa location rarely occurs and, based on the cases reported in the literature, commonly has a poor prognosis. CASE PRESENTATION: A newborn female, diagnosed prenatally with hydrocephalus, is presented at birth with increasing head circumference and Parinaud's syndrome. Magnetic resonance imaging scans demonstrated a huge posterior fossa tumor with obstructive hydrocephalus. At surgery, through a suboccipital craniotomy, complete excision was achieved of a histological-proven immature teratoma. The infant received adjuvant chemotherapy for 1 year. She had normal neurological development and remained tumor-free through her 20-year follow-up. CONCLUSION: The authors report this rare case of congenital posterior fossa teratoma with long-term outcome, and the literature is reviewed.

Infusion of 5-Azacytidine (5-AZA) into the fourth ventricle or resection cavity in children with recurrent posterior Fossa Ependymoma: a pilot clinical trial.

BACKGROUND: DNA methylation inhibitors are logical therapeutic candidates for ependymomas originating in the posterior fossa of the brain. Our objective was to test the safety of infusing 5-Azacytidine (5-AZA), a DNA methylation inhibitor, directly into cerebrospinal fluid (CSF) spaces of the fourth ventricle or tumor resection cavity in children with recurrent ependymoma originating in the posterior fossa. MATERIALS AND METHODS: In patients with recurrent ependymoma whose disease originated in the posterior fossa, a maximal safe subtotal tumor resection was performed. At the conclusion of the tumor resection, a catheter was surgically placed into the fourth ventricle or tumor resection cavity and attached to a ventricular access device. CSF flow from the posterior fossa to the sacrum was confirmed by CINE phase contrast magnetic resonance imaging (MRI) postoperatively. 12 consecutive weekly 10 milligram (mg) infusions of 5-Azacytidine (AZA) were planned. Disease response was monitored with MRI scans and CSF cytology. RESULTS: Six patients were enrolled. One patient was withdrawn prior to planned 5-AZA infusions due to surgical complications after tumor resection. The remaining five patients received 8, 12, 12, 12, and 12 infusions, respectively. There were no serious adverse events or new neurological deficits attributed to 5-AZA infusions. All five patients with ependymoma who received 5-AZA infusions had progressive disease. Two of the five patients, however, were noted to have decrease in the size of at least one intraventricular lesion. CONCLUSION: 5-AZA can be infused into the fourth ventricle or posterior fossa tumor resection cavity without causing neurological toxicity. Future studies with higher doses and/or increased dosing frequency are warranted.

Brainstem Injury in Pediatric Patients With Posterior Fossa Tumors Treated With Proton Beam Therapy and Associated Dosimetric Factors.

PURPOSE: Proton radiation therapy is commonly used in young children with brain tumors for its potential to reduce late effects. However, some proton series report higher rates of brainstem injury (0%-16%) than most photon series (2.2%-8.6%). We report the incidence of brainstem injury and a risk factor analysis in pediatric patients with posterior fossa primary tumors treated with proton radiation therapy at our institution. METHODS AND MATERIALS: The study included 216 consecutive patients treated between 2000 and 2015. Dosimetry was available for all but 4 patients. Grade 2 to 5 late brainstem toxicity was assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. RESULTS: The histologies include medulloblastoma (n=154, 71.3%), ependymoma (n=56, 25.9%), and atypical teratoid rhabdoid tumor (n=6, 2.8%). The median age at irradiation was 6.6 years (range, 0.5-23.1 years); median dose, 54 gray relative biological effectiveness (Gy RBE) (range, 46.8-59.4 Gy RBE); and median follow-up period, 4.2 years (range, 0.1-15.3 years) among 198 survivors. Of the patients, 83.3% received chemotherapy; 70.4% achieved gross total resection. The crude rate of injury was 2.3% in all patients, 1.9% in those with medulloblastoma, 3.6% in those with ependymoma, and 0% in those with atypical teratoid rhabdoid tumor. The 5-year cumulative incidence of injury was 2.0% (95% confidence interval, 0.7%-4.8%). The median brainstem dose (minimum dose received by 50% of brainstem) in the whole cohort was 53.6 Gy RBE (range, 16.5-56.8 Gy RBE); maximum point dose within the brainstem (Dmax), 55.2 Gy RBE (range, 48.4-60.5 Gy RBE); and mean dose, 50.4 Gy RBE (range, 21.1-56.7 Gy RBE). In the 5 patients with injury, the median minimum dose received by 50% of the brainstem was 54.6 Gy RBE (range, 50.2-55.1 Gy RBE); Dmax, 56.2 Gy RBE (range, 55.0-57.1 Gy RBE); mean dose, 51.3 Gy RBE (range, 45.4-54.4 Gy RBE); and median volume of the brainstem receiving ≥55 Gy RBE (V55), 27.4% (range, 0%-59.4%). Of the 5 patients with injury, 4 had a brainstem Dmax in the highest quartile (≥55.8 Gy RBE, P = .016) and a V55 in the highest tertile (>6.0%) of the cohort distribution (P = .047). Of the 5 patients with injury, 3 were aged >6 years (age range, 4.1-22.8 years), and 4 of 5 patients received chemotherapy and achieved gross total resection. CONCLUSIONS: The incidence of injury in pediatric patients with posterior fossa tumors is consistent with previous reports in the photon setting. Our data suggest that when Dmax and V55 are kept <55.8 Gy RBE and ≤6.0%, respectively, the 5-year rate of radiation brainstem injury would be <2%.

Phase-contrast cerebrospinal fluid flow magnetic resonance imaging in qualitative evaluation of patency of CSF flow pathways prior to infusion of chemotherapeutic and other agents into the fourth ventricle.

PURPOSE: Nuclear medicine studies have previously been utilized to assess for blockage of cerebrospinal fluid (CSF) flow prior to intraventricular chemotherapy infusions. To assess CSF flow without nuclear medicine studies, we obtained cine phase-contrast MRI sequences that assess CSF flow from the fourth ventricle down to the sacrum. METHODS: In three clinical trials, 18 patients with recurrent malignant posterior fossa tumors underwent implantation of a ventricular access device (VAD) into the fourth ventricle, either with or without simultaneous tumor resection. Prior to infusing therapeutic agents into the VAD, cine MRI phase-contrast CSF flow sequences of the brain and total spine were performed. Velocity encoding (VENC) of 5 and 10 cm/s was used to confirm CSF flow from the fourth ventricular outlets to the cervical, thoracic, and lumbar spine. Qualitative CSF flow was characterized by neuroradiologists as present or absent. RESULTS: All 18 patients demonstrated CSF flow from the outlets of the fourth ventricle down to the sacrum with no evidence of obstruction. One of these patients, after disease progression, subsequently showed obstruction of CSF flow. No patient required a nuclear medicine study to assess CSF flow prior to initiation of infusions. Fourteen patients have received infusions to date, and none has had neurological toxicity. CONCLUSIONS: CSF flow including the fourth ventricle and the total spine can be assessed noninvasively with phase-contrast MRI sequences. Advantages over nuclear medicine studies include avoiding both an invasive procedure and radiation exposure.

Infantile Hemangioma of the Posterior Fossa in a Newborn: Early Management and Long-Term Follow-up.

A 21-day-old male infant was admitted with signs of intracranial hypertension. Brain magnetic resonance imaging (MRI) revealed a voluminous mass in the posterior fossa with an intense peripheral enhancement on T1 images with gadolinium. The child was treated secondarily by surgical decompression of the posterior fossa and the lesion was biopsied. The pathological findings indicated infantile hemangioma. Treatment with oral prednisolone was initiated at 3 months, given the lack of tumor involution. Six months after corticotherapy was stopped, repeated MRIs indicated a significant reduction in tumor size and then complete disappearance. Psychometric evaluation was performed at the age of 15 years, showing heterogeneous cognitive disabilities, with verbal abilities superior to nonverbal abilities and delayed motor development. Neurological examination was normal with no focal deficit. To our knowledge, this is the first published case reporting the long-term evolution of a patient with neonatal intracerebral hemangioma. We conclude that psychometric evaluations should be part of the long-term follow-up of children who have had an intracranial capillary hemangioma.

RETROSPECTIVE COMPARISON OF THREE-DIMENSIONAL CONFORMAL RADIATION THERAPY VS. PREDNISOLONE ALONE IN 30 CASES OF CANINE INFRATENTORIAL BRAIN TUMORS.

Infratentorial tumors are relatively infrequent in dogs and a lack of data makes it difficult to offer prognostic information. Untreated, dogs with these neoplasms have shorter survival times than those with supratentorial tumors. The role of radiation therapy (RT) in the management of infratentorial tumors is poorly defined and tumoral/peritumoral swelling in this site is a potential cause of serious acute side effects. The aim of this retrospective, cohort study was to describe cases of infratentorial tumors treated with fractionated three-dimensional conformal RT (3D CRT) and glucocorticoids (GC), and compare outcomes and survival with dogs affected by tumors in the same location that received GC alone. Thirty patients with a MRI diagnosis of infratentorial tumors were recruited (15 received RT and GC and 15 GC alone). None had mentation changes at presentation. For both groups, MRI and medical records were reviewed; and factors associated with survival were evaluated with Kaplan-Meier product limit survival and Cox regression analysis. Overall median survival time (MST) was 294 days (95% CI 42-545). The MST in the RT group was 756 days (95% CI 209-1302) vs. 89 days (95% CI 34.7-143.3 days) for those dogs treated palliatively with GC alone. This difference was statistically significant (P = 0.001). No other factors (including neurological signs, MRI features, tumor volume and total RT dose) were statistically associated with survival in the RT group. This study suggests that 3D CRT offers a survival advantage for dogs with infratentorial tumors compared to GC alone, and significant complications are uncommon.

Pencil beam scanning proton therapy for pediatric intracranial ependymoma.

To assess the clinical outcome and late side effect profile of pencil beam scanning proton therapy (PT) delivered to children with intracranial ependymoma. Between July-2004 and March-2013, 50 patients with intracranial ependymoma (n = 46, grade 3) received involved-field PT at Paul Scherrer Institute (PSI). Median age at time of PT was 2.6 years (range 1.1-15.2). Thirty-six patients had infratentorial and 14 supratentorial ependymomas. Seventeen patients presented with macroscopic residual disease after subtotal resection before starting PT (8 with ≤1.5 cc and 9 with >1.5 cc residual tumor respectively). Forty-three (86 %) patients received post-operative chemotherapy before PT according to protocols; 44 (88 %) patients younger than 5 years required general anesthesia. Median prescribed dose was 59.4 Gy (RBE) (range 54-60) delivered in 1.8-2 Gy (RBE) per fraction. Late toxicity was assessed according to CTCAE v4.0. With a mean follow-up time of 43.4 months (range 8.5-113.7) seven patients experienced local failure (6 with infratentorial tumors and 1 with supratentorial tumor); four of the local failures were in patients with residual disease ≥1.5 cc at the time of PT and 3 without residual macroscopic disease. Five patients died from tumor progression. Actuarial 5-year Local Control rates were 78 ± 7.5 % and 5-year OS rates were 84 ± 6.8 %. Three patients developed grade ≥3 toxicity: 2 developed unilateral deafness (infratentorial tumors infiltrating into the internal acoustic canal), one patient developed a fatal brainstem necrosis. Repeated general anesthesia in children younger than 5 years was delivered without complications. Our data indicate the safety and the effectiveness of PT for pediatric ependymomas. Local control and survival rates are encouraging considering the high grade histology in 92 % of the patients and the number of patients with residual tumor ≥1.5 cc. The rates of late effects compare favorably with published photon-treated cohorts.

Photodynamic therapy (PDT) for malignant brain tumors--where do we stand?

INTRODUCTION: What is the current status of photodynamic therapy (PDT) with regard to treating malignant brain tumors? Despite several decades of effort, PDT has yet to achieve standard of care. PURPOSE: The questions we wish to answer are: where are we clinically with PDT, why is it not standard of care, and what is being done in clinical trials to get us there. METHOD: Rather than a meta-analysis or comprehensive review, our review focuses on who the major research groups are, what their approaches to the problem are, and how their results compare to standard of care. Secondary questions include what the effective depth of light penetration is, and how deep can we expect to kill tumor cells. CURRENT RESULTS: A measurable degree of necrosis is seen to a depth of about 5mm. Cavitary PDT with hematoporphyrin derivative (HpD) results are encouraging, but need an adequate Phase III trial. Talaporfin with cavitary light application appears promising, although only a small case series has been reported. Foscan for fluorescence guided resection (FGR) plus intraoperative cavitary PDT results were improved over controls, but are poor compared to other groups. 5-Aminolevulinic acid-FGR plus postop cavitary HpD PDT show improvement over controls, but the comparison to standard of care is still poor. CONCLUSION: Continued research in PDT will determine whether the advances shown will mitigate morbidity and mortality, but certainly the potential for this modality to revolutionize the treatment of brain tumors remains. The various uses for PDT in clinical practice should be pursued.

Drop metastases to the spinal cord from infratentorial glioblastoma multiforme in post-temozolomide era.

Drop metastases from glioblastoma multiforme (GBM) to the spinal cord are extremely rare in clinical practice. We report herewith multiple drop metastases to the cervical and thoracic spinal cord presenting as paraplegia in a patient treated initially with tumor resection followed by chemoradiation and later with temozolomide-.based adjuvant chemotherapy.

Endocrinologic Consequences of Pediatric Posterior Fossa Tumours.

Intracranial tumors are the second most frequent malignancies in children and posterior fossa is a common location for these neoplasias during childhood. Recent advances in surgical techniques, radiotherapy and chemotherapy resulted in dramatic increase in the survival rates of these children, however they are still source of a significant morbidity and mortality. Endocrinological complications and late sequelae of childhood posterior fossa tumours are common among the survivors of these tumours and include growth retardation, hypothyroidism, pubertal disorders, gonadal dysfunction and osteopenia. These complications have significant impact on the quality of life of the survivors of childhood posterior fossa tumours. In this paper, the frequency, etiology, and management of these complications will be reviewed.

Early clinical outcomes using proton radiation for children with central nervous system atypical teratoid rhabdoid tumors.

PURPOSE: Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon and aggressive tumor that often affects infants. Irradiation improves survival but has traditionally been avoided in patients under the age of 3 due to the increasing risk of neurocognitive side effects. We report the first cohort of AT/RT patients treated with proton therapy. METHODS AND MATERIALS: All patients with AT/RT treated at Massachusetts General Hospital (MGH) Frances H. Burr Proton Beam Therapy Benter between July 2004 and November 2011 were included in this study. All patients were treated with 3-dimensional conformal proton therapy (3D-CPT). RESULTS: Ten consecutive patients of a median 2.3 years of age and with a median follow-up of 27.3 months (range, 11.3-99.4 months) were identified. Two patients suffered distant relapse; 1 patient was successfully treated with involved field irradiation and chemotherapy, while the second patient died of disease. At last follow-up, 9 patients were alive without evidence of disease. Proton radiation demonstrated increasing sparing of the cerebrum, temporal lobe, cochlea, and hypothalamus. CONCLUSIONS: Initial clinical outcomes with proton therapy are favorable. The advantages of proton therapy are particularly suited to the treatment of AT/RT, a tumor that often requires irradiation treatment at an age when avoiding irradiation to healthy tissues is most desirable.

Second-look surgery for ependymoma: the Italian experience.

OBJECT: Complete ependymoma resection ensures a better prognosis for children with this tumor, but the complete excision of infratentorial ependymomas involves serious risks. Second-look surgery for tumor remnants may be less harmful and enable complete removal. There is a potential, although still unclear, role for neoadjuvant chemotherapy in preparation for further surgery. METHODS: Since 1994, the authors have adopted two successive protocols for intracranial ependymoma, both including a phase of adjuvant chemotherapy for children with surgical tumor remnants with a plan for potential second-look surgery before radiotherapy. RESULTS: In the first protocol, 9 of 63 children underwent further surgery, and 6 became tumor free with no additional sequelae. Their prognosis for progression-free survival and freedom from local relapse was comparable to that of children who were operated on only once. In the second protocol, efforts were made to achieve complete resection and 29 of 110 patients underwent reoperations: 9 after the first surgery, 17 after chemotherapy, and 3 soon after radiotherapy. Fourteen of the 29 patients became tumor free, 1 of them with worsening neurological symptoms. The outcome of the 66 patients who became tumor free after 1 operation was compared with that of the 14 who became tumor free after reoperation. The 3-year progression-free survival of the 66 patients compared with the 14 other patients was 71.4% ± 6.9% and 90% ± 9.5%, respectively; the 3-year freedom from local relapse was 84.7% ± 5.9% and 90% ± 9.5%, respectively; and the 3-year overall survival was 85.9% ± 5.4% and 87.5% ± 11.7%, respectively. CONCLUSIONS: Second-look surgery proved feasible with no major morbidity, and results improved with time. Local tumor control was comparable in patients undergoing 1 or more resections.

Comparison of permanent hair loss in children with standard risk PNETS of the posterior fossa following radiotherapy alone or chemotherapy and radiotherapy after surgical resection.

Hair loss was compared between surgery followed by craniospinal radiotherapy (CSRT) or chemotherapy then CSRT (C-CSRT) for medulloblastoma. The proportion of patients exhibiting hair loss in the cranial field was 70.0% (C-CSRT) versus 30.0% (CSRT) (95% CI: 14.7% to 58.9%; P = 0.002). The C-CSRT group also experienced more virtual/complete hair loss over the posterior fossa boost. Age was a significant contributor to hair loss in the cranial field. Persistent significant hair loss is an under-reported late effect of treatment that could influence quality of survival and should be considered in future trial design.

Infratentorial brain metastases of pediatric non-epithelial malignant tumors: three case reports.

Three pediatric patients with infratentorial metastatic non-epithelial malignant brain tumors were successfully treated by radical surgical resection followed by aggressive radiochemotherapy. One patient with neuroblastoma and two with rhabdomyosarcoma were successfully treated by first line multimodal treatments, but developed infratentorial metastasis after several months of remission. All patients revealed intracranial metastases manifesting as rapidly progressing neurological symptoms caused by mass effect in the posterior fossa. Radical surgical resection was performed without morbidity. The patients were then treated by adjuvant radiochemotherapy with or without autologous peripheral blood stem cell transplantation, resulting in complete remission. Two patients developed extracranial recurrences 4 months after the treatments for intracranial metastases. One patient was treated by second high-dose chemotherapy with allogeneic cord blood transplantation, again resulting in complete remission. Another patient was treated by second chemotherapy and maintaining stable disease. The other patient maintained complete remission. All three patients were alive without neurological deficit for 8, 11, and 12 months after diagnosis of brain metastasis. Patients with infratentorial brain metastases of highly malignant pediatric non-epithelial tumors are in a severe clinical state, but still can have longer and useful lives with aggressive multimodal treatments combined with radical surgical resection.

Infant ependymoma in a 10-year AIEOP (Associazione Italiana Ematologia Oncologia Pediatrica) experience with omitted or deferred radiotherapy.

PURPOSE: The protocols of the 1990s omitted or delayed irradiation, using upfront chemotherapy to spare the youngest children with ependymoma the sequelae of radiotherapy (RT). We treated 41 children under the age of 3 years with intracranial ependymoma between 1994 and 2003. PATIENTS AND METHODS: After surgery, chemotherapy was given as follows: regimen I with four blocks of vincristine, high-dose methotrexate 5 g/m(2), and cyclophosphamide 1.5 g/m(2) alternating with cisplatin 90 mg/m(2) plus VP16 450 mg/m(2) for 14 months; subsequently, regimen II was used: VEC (VCR, VP16 300 mg/m(2), and cyclophosphamide 3 g/m(2)) for 6 months. Radiotherapy was planned for residual tumor after the completion of chemotherapy or for progression. RESULTS: We treated 23 boys and 18 girls who were a median 22 months old; 14 were given regimen I, 27 were given regimen II; 22 underwent complete resection, 19 had residual tumor. Ependymoma was Grade 2 in 25 patients and Grade 3 in 16; tumors were infratentorial in 37 patients and supratentorial in 4. One child had intracranial metastases; 29 had progressed locally after a median 9 months. Event-free survival was 26% at 3 and 5 years and 23% at 8 years. One child died of sepsis, and another developed a glioblastoma 72 months after RT. Progression-free survival was 27% at 3, 5, and 8 years, and overall survival was 48%, 37%, and 28% at 3, 5, and 8 years, respectively. Of the 13 survivors, 6 never received RT; their intellectual outcome did not differ significantly in those children than in those without RT. CONCLUSIONS: Our results confirm poor rates of event-free survival and overall survival for up-front chemotherapy in infant ependymoma. No better neurocognitive outcome was demonstrated in the few survivors who never received RT.

Differences in supratentorial damage of white matter in pediatric survivors of posterior fossa tumors with and without adjuvant treatment as detected by magnetic resonance diffusion tensor imaging.

PURPOSE: To elucidate morphologic correlates of brain dysfunction in pediatric survivors of posterior fossa tumors by using magnetic resonance diffusion tensor imaging (DTI) to examine neuroaxonal integrity in white matter. PATIENTS AND METHODS: Seventeen medulloblastoma (MB) patients who had received surgery and adjuvant treatment, 13 pilocytic astrocytoma (PA) patients who had been treated only with surgery, and age-matched healthy control subjects underwent magnetic resonance imaging on a 3-Tesla system. High-resolution conventional T1- and T2-weighted magnetic resonance imaging and DTI data sets were obtained. Fractional anisotropy (FA) maps were analyzed using tract-based spatial statistics, a part of the Functional MRI of the Brain Software Library. RESULTS: Compared with control subjects, FA values of MB patients were significantly decreased in the cerebellar midline structures, in the frontal lobes, and in the callosal body. Fractional anisotropy values of the PA patients were not only decreased in cerebellar hemispheric structures as expected, but also in supratentorial parts of the brain, with a distribution similar to that in MB patients. However, the amount of significantly decreased FA was greater in MB than in PA patients, underscoring the aggravating neurotoxic effect of the adjuvant treatment. CONCLUSIONS: Neurotoxic mechanisms that are present in PA patients (e.g., internal hydrocephalus and damaged cerebellar structures affecting neuronal circuits) contribute significantly to the alteration of supratentorial white matter in pediatric posterior fossa tumor patients.

Pharmacokinetic analysis of etoposide distribution after administration directly into the fourth ventricle in a piglet model.

We hypothesize that infusion of chemotherapeutic agents directly into the fourth ventricle potentially may play a role in treating malignant posterior fossa brain tumors. Accordingly, we used a piglet model developed in our laboratory to test the safety of etoposide infusions into the fourth ventricle and to study the pharmacokinetics associated with these infusions. In 5 piglets, closed-tip silicone catheters were inserted into the fourth ventricle and lumbar cistern. Five consecutive daily infusions of etoposide (0.5 mg) were administered via the fourth ventricle catheter. Serum and CSF from both catheters were sampled for measurement of etoposide level by reversed-phase high performance liquid chromatography (HPLC). For CSF samples, area under the concentration-time curve (AUC) was calculated. Piglets underwent daily neurological examinations, a 4.7 Tesla MRI scan, and then were sacrificed for post-mortem brain examination. No neurological deficits or signs of meningitis were caused by intraventricular chemotherapy infusions. MRI scans showed catheter placement within the fourth ventricle but no signal changes in the brain stem or cerebellum. In all piglets, the mean fourth ventricular CSF peak etoposide level exceeded the mean peak lumbar etoposide levels by greater than 10-fold. Statistically significant differences between fourth ventricle and lumbar AUC were noted at peaks (DeltaAUC = 3384196 ng h/ml with 95%CI: 1758625, 5009767, P = 0.0044) and at all collection time points (DeltaAUC = 1422977 ng h/ml with 95%CI: 732188, 2113766, P = 0.0046) but not at troughs (DeltaAUC = -29546 ng h/ml (95%CI: -147526, 88434.2, P = 0.5251). Serum etoposide was absent at two and four hours after intraventricular infusions in all animals. Pathological analysis demonstrated meningitis, choroid plexitis, and ependymitis in the fourth and occasionally lateral ventricles. Etoposide can be infused directly into the fourth ventricle without clinical or radiographic evidence of damage. Autopsy examination revealed ventriculitis and meningitis which did not have a clinical correlate. Etoposide does not distribute evenly throughout CSF spaces after administration into the fourth ventricle, and higher peak CSF levels are observed in the fourth ventricle than in the lumbar cistern.

Core neurocognitive functions in children treated for posterior fossa tumors.

Identifying cognitive deficits associated with pediatric brain tumors and their treatment is important in delineating the mechanisms of intellectual decline often associated with these diseases. The authors evaluated sustained attention, information processing speed, working memory, and IQ in 64 patients with posterior fossa tumors, including those treated with either: (a) surgery and cranial radiation (n = 32), and (b) surgery without radiation (n = 32). Ten patients treated for non-CNS solid tumors were included as a comparison group. The authors also examined the impact of relevant demographic and medical variables on neurocognitive outcome. The authors found that neither age at, nor time since, diagnosis predicted cognitive outcome in this sample. Further, sustained attention and working memory were largely intact and there were no differences between groups. Patients treated with cranial radiation demonstrated lowered short-form IQ and slow information processing speed: Patients treated with cranial radiation and who experienced postsurgical complications demonstrated the poorest performance. The authors consider information processing speed to be an excellent candidate mechanism in understanding the impact of cranial radiation on intellectual outcome.