Superiority of Multidetector Computed Tomography With 3-Dimensional Volume Rendering Over Plain Radiography in the Assessment of Spinal Surgical Instrumentation Complications in Patients With Cancer.

OBJECTIVE: The objective of this study was to compare multidetector computed tomography (MDCT) images with volume-rendered translucent display (VRTLD) series to plain radiographs for evaluating spinal surgical instrumentation after resection and reconstruction for spinal malignancies. METHODS: In 44 patients with tumor resection and spinal reconstruction, 17 with complications, 3 neuroradiologists evaluated plain radiographs, MDCT images alone, VRTLD images alone, and MDCT images with VRTLD images for identifying complications in 3 categories: subsidence/migration, construct fracture, and screw loosening. Each category was scored as 1 (complications), 2 (no complications), or 3 (not sure), and the minimum score was used for analyses. Clinical/surgical outcomes were the reference standard. RESULTS: Sensitivity, specificity, and accuracy (95% confidence interval), respectively, were as follows: MDCT/VRTLD, 100%, 100%, 100% (91.96%-100.00%); MDCT alone, 88.24%, 100%, 95.45% (84.53%-99.44%); VRTLD alone, 82.35%, 96.3%, 90.91% (78.33%-97.47%); plain radiographs, 52.94%, 100%, 81.82% (67.29%-91.81%). CONCLUSIONS: Multidetector computed tomography with VRTLD series seems best for evaluation of spinal instrumentation after tumor resection and reconstruction.

Ganglioglioma in children and young adults: single institution experience and review of the literature.

BACKGROUND: Ganglioglioma (GG) is a rare mixed glial-neuronal neoplasm accounting for 0.5-5% of all pediatric central nervous system (CNS) tumors. Rarity of this tumor has precluded defining robust treatment guidelines. This retrospective study evaluates the prognostic factors and outcomes of this rare neoplasm. PATIENTS AND METHODS: Retrospective analysis of 55 patients with GG was conducted to describe clinical findings, and outcomes. Kaplan-Meier survival and Cox-regression analyses were performed to assess the overall survival (OS) and progression-free survival (PFS). RESULTS: The mean age at diagnosis was 11.8 years (range 1-21 years) with a median follow-up period of 9.5 years. 53 patients (92.7%) had low grade GG and 2 patients had anaplastic GG. 25 patients had tumor progression, whose median PFS was 12 years. Six patients with low grade GG progressed to a higher grade, with median survival of 9.1 month after transformation. The 5 and 10 year PFS were 65 and 57%, respectively. The 5 and 10 year OS was 96 and 86% respectively. 8 of the 19 (42%) samples tested demonstrated positivity for the BRAF V600E mutation. Multivariate Cox regression analyses showed location and extent of resection were significant factors for PFS and presence of metastatsis attained significance for OS. CONCLUSION: This is the one of the largest retrospective study of pediatric GG. Identifying clinical variables, which could stratify these tumors into low- and high-risk groups might help to profile a risk-based therapeutic strategy. Collaborative multiinstitutional prospective studies are warranted to delineate treatment consensus and investigate prognostic factors.

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.

Progression-free survival of children with localized ependymoma treated with intensity-modulated radiation therapy or proton-beam radiation therapy.

BACKGROUND: The treatment for childhood intracranial ependymoma includes maximal surgical resection followed by involved-field radiotherapy, commonly in the form of intensity-modulated radiation therapy (IMRT). Proton-beam radiation therapy (PRT) is used at some centers in an effort to decrease long-term toxicity. Although protons have the theoretical advantage of a minimal exit dose to the surrounding uninvolved brain tissue, it is unknown whether they have the same efficacy as photons in preventing local recurrence. METHODS: A retrospective review of medical records from September 2000 to April 2013 was performed. Seventy-nine children with newly diagnosed localized intracranial ependymomas treated with either IMRT (n = 38) or PRT (n = 41) were identified, and progression-free survival (PFS) was analyzed with Kaplan-Meier and Cox multivariate analyses. RESULTS: The median age at diagnosis was 3.7 years for all patients (range, 0.4-18.7 years). There were 54 patients with infratentorial tumors (68% of the total population). Patients treated with PRT were younger (median age, 2.5 vs 5.7 years; P = .001) and had a shorter median follow-up (2.6 vs 4.9 years; P < .0001). Gross total resection (GTR) was achieved in 67 patients (85%) and was more frequent in the PRT group versus the IMRT group (93% vs 76%; P = .043). The 3-year PFS rates were 60% and 82% with IMRT and PRT, respectively (P = .031). CONCLUSIONS: Children with localized ependymomas treated with PRT have a 3-year PFS rate comparable to that of children treated with IMRT. This analysis suggests that local control is not compromised by the use of PRT. The data also support GTR as the only prognostic factor for PFS. Cancer 2017;123:2570-78. © 2017 American Cancer Society.

Primary intracranial soft tissue sarcomas in children, adolescents, and young adults: single institution experience and review of the literature.

There is a paucity of literature reporting the outcome of intracranial sarcomas (IS) in children, adolescents, and young adults (CAYA). A multimodal therapeutic approach is commonly used, with no well-established treatment consensus. We conducted a retrospective review of CAYA with IS, treated at our institution, to determine their clinical findings, treatments, and outcomes. Immunohistochemistry (PDGFRA and EGFR) and DNA sequencing were performed on 5 tumor samples. A literature review of IS was also conducted. We reviewed 13 patients (median age, 7 years) with a primary diagnosis of IS between 1990 and 2015. Diagnoses included unclassified sarcoma (n = 9), chondrosarcoma (n = 2), and rhabdomyosarcoma (n = 2). Five patients underwent upfront gross total resection (GTR) of the tumor. The 5-drug regimen (vincristine, doxorubicin, cyclophosphamide, etoposide, and ifosfamide) was the most common treatment used. Nine patients died due to progression or recurrence (n = 8) or secondary malignancy (n = 1). The median follow-up period of the 4 surviving patients was 1.69 years (range 1.44-5.17 years). The 5-year progression-free survival and overall survival rates were 21 and 44 %, respectively. BRAF, TP53, KRAS, KIT, ERBB2, MET, RET, ATM, and EGFR mutations were detected in 4 of the 5 tissue samples. All 5 samples were immunopositive for PDGFRA, and only 2 were positive for EGFR. IS remain a therapeutic challenge due to high progression and recurrence rates. Collaborative multi-institutional studies are warranted to delineate a treatment consensus and investigate tumor biology to improve the disease outcome.

Methotrexate administration directly into the fourth ventricle in children with malignant fourth ventricular brain tumors: a pilot clinical trial.

We hypothesize that chemotherapy can be safely administered directly into the fourth ventricle to treat recurrent malignant brain tumors in children. For the first time in humans, methotrexate was infused into the fourth ventricle in children with recurrent, malignant brain tumors. A catheter was surgically placed into the fourth ventricle and attached to a ventricular access device. Cerebrospinal fluid (CSF) flow was confirmed by CINE MRI postoperatively. Each cycle consisted of 4 consecutive daily methotrexate infusions (2 milligrams). Disease response was monitored with serial MRI scans and CSF cytologic analysis. Trough CSF methotrexate levels were sampled. Five patients (3 with medulloblastoma and 2 with ependymoma) received 18, 18, 12, 9, and 3 cycles, respectively. There were no serious adverse events or new neurological deficits attributed to methotrexate. Two additional enrolled patients were withdrawn prior to planned infusions due to rapid disease progression. Median serum methotrexate level 4 h after infusion was 0.04 µmol/L. Range was 0.02-0.13 µmol/L. Median trough CSF methotrexate level 24 h after infusion was 3.18 µmol/L (range 0.53-212.36 µmol/L). All three patients with medulloblastoma had partial response or stable disease until one patient had progressive disease after cycle 18. Both patients with ependymoma had progressive disease after 9 and 3 cycles, respectively. Low-dose methotrexate can be infused into the fourth ventricle without causing neurological toxicity. Some patients with recurrent medulloblastoma experience a beneficial anti-tumor effect both within the fourth ventricle and at distant sites.

Preliminary experience with diffusion tensor imaging before and after re-irradiation treatments in children with progressive diffuse pontine glioma.

PURPOSE: The purpose of this study is to evaluate quantitative changes in diffusion tensor imaging (DTI) tractography and fractional anisotropy (FA) of the pons along with clinical correlation, in patients who receive re-irradiation for progressive diffuse intrinsic pontine glioma (DIPG). METHODS: A retrospective case review of children with progressive DIPG who received re-irradiation at our institution from 2007 to 2011 after approval from the Institutional Review Board was performed. Tractography analysis and FA were analyzed pre and post-re-irradiation, and correlation with clinical features and MR imaging was performed. RESULTS: DTI analysis showed reduced values of FA on tumor progression. Increase in the FA values was noted after re-irradiation in these patients. This correlated with clinical improvement. These changes were concordant with the 3D tractography analysis which showed better visualization of the corticospinal tracts as they course through brainstem and posterior transverse pontine fibers following re-irradiation. CONCLUSION: Serial changes in the FA values using DTI could provide clinically more correlative information in patients with progressive DIPG, who receive re-irradiation. Though the use and results of this modality has been reported in the newly diagnosed DIPG before, evaluation of DTI in children who receive re-irradiation for progressive DIPG has not been reported earlier. Though limited by the small sample size and treatment variability, this study for the first time shows the preliminary experience, potential, and likely efficacy of complementing DTI analysis to routine neuroimaging also in patients re-irradiated for progressive DIPG to better assess treatment response.

Treatment of recurrent diffuse intrinsic pontine glioma: the MD Anderson Cancer Center experience.

Recurrent diffuse intrinsic pontine gliomas (DIPG) are traditionally treated with palliative care since no effective treatments have been described for these tumors. Recently, clinical studies have been emerging, and individualized treatment is attempted more frequently. However, an informative way to compare the treatment outcomes has not been established, and historical control data are missing for recurrent disease. We conducted a retrospective chart review of patients with recurrent DIPG treated between 1998 and 2010. Response progression-free survival and possible influencing factors were evaluated. Thirty-one patients were identified who were treated in 61 treatment attempts using 26 treatment elements in 31 different regimens. The most frequently used drugs were etoposide (14), bevacizumab (13), irinotecan (13), nimotuzumab (13), and valproic acid (13). Seven patients had repeat radiation therapy to the primary tumor. Response was recorded after 58 treatment attempts and was comprised of 0 treatment attempts with complete responses, 7 with partial responses, 20 with stable diseases, and 31 with progressive diseases The median progression-free survival after treatment start was 0.16 years (2 months) and was found to be correlated to the prior time to progression but not to the number of previous treatment attempts. Repeat radiation resulted in the highest response rates (4/7), and the longest progression-free survival. These data provide a basis to plan future clinical trials for recurrent DIPG. Repeat radiation therapy should be tested in a prospective clinical study.

Sequential Diffusion Tensor Imaging and Magnetic Resonance Spectroscopy in Patients Undergoing Reirradiation for Progressive Diffuse Intrinsic Pontine Glioma.

PURPOSE: Diffusion tensor imaging for evaluation of white matter tracts is used with magnetic resonance spectroscopy (MRS) to improve management of diffuse intrinsic pontine glioma (DIPG). Changes in the apparent diffusion coefficient (ADC), fractional anisotropy (FA), and tumor metabolite ratios have been reported after initial radiation for DIPG, but these markers have not been studied sequentially in patients undergoing reirradiation for progressive DIPG. Here, we report a case series of 4 patients who received reirradiation for progressive DIPG on a prospective clinical trial in which we evaluated quantitative changes in FA, ADC, and tumor metabolites and qualitative changes in white matter tracts. METHODS AND MATERIALS: The median reirradiation dose was 25.2 Gy (24-30.8 Gy). Fiber tracking was performed using standard tractography analysis. The FA and ADC values for the corticospinal and medial lemniscus tracts were calculated before and after reirradiation. Multivoxel MRS was performed. Findings were correlated with clinical features and conventional MRI of tumors. RESULTS: All patients had an initial response to reirradiation as shown by a decrease in tumor size. In general, FA increased with disease response and decreased with progression, whereas ADC decreased with disease response and increased with progression. At second progression, the FA fold change relative to values during disease response decreased in both patients with available imaging at second progression. Visualization of tracts demonstrated robust reconstitution of previously disrupted paths during tumor response; conversely, there was increased fiber tract disruption and infiltration during tumor progression. The MRS analysis revealed a decrease in choline:creatinine and choline:N-acetylaspartate ratios during tumor response and increase during progression. CONCLUSIONS: Distinct changes in white matter tracts and tumor metabolism were observed in patients with DIPG undergoing reirradiation on a prospective clinical trial. Changes related to tumor response and progression were observed after 24 to 30.8 Gy reirradiation.

Rosai-Dorfman disease in neuroradiology: imaging findings in a series of 10 patients.

OBJECTIVE: Rosai-Dorfman disease is a rare disorder characterized histologically by lymphatic sinus dilatation due to histiocyte proliferation. Our goal was to describe the CT, MRI, and (18)F-FDG (FDG) PET findings in a series of patients with this diagnosis. MATERIALS AND METHODS: We retrospectively reviewed the imaging studies of 10 patients with pathologically confirmed Rosai-Dorfman disease who were treated in our institution between January 2004 and December 2007. RESULTS: We found the following areas of general involvement: three intracranial, seven head and neck, and three spinal, with some patients having more than one site. Specific sites of involvement included the following: intracranial meninges, n = 2; pituitary, n = 2; lacrimal gland, n = 1; paranasal sinus, n = 3; neck lymph nodes, n = 6; salivary gland, n = 3; tonsil, n = 1; skin, n = 1; spinal meninges, n = 2; vertebral body, n = 1; and thymus, n = 1. The MRI characteristics of the involved areas were generally T1 isointense, T2 isointense, diffusion isointense to gray matter, and intensely enhancing with gadolinium chelate contrast agents. CT images generally showed the lesions were hyperdense to gray matter and intensely enhancing. FDG PET showed variable uptake, with nodal and lacrimal disease generally being FDG avid and other sites not. CONCLUSION: Rosai-Dorfman disease has a protean imaging appearance but most frequently presents as neck lymphadenopathy. The disease is frequently multifocal, and a diagnosis in one area should prompt suspicion that other sites may be involved also.

99mTc-sestamibi scan differentiates tumor from other contrast enhancing tissue in choroid plexus tumors.

Choroid plexus tumors are rare brain tumors which account for 0.4% to 0.6% among brain tumors. Tumor resection is known to be of large prognostic impact, and re-resection of residual tumors is a part of standard care. However, after multiple resections it can become difficult to differentiate tumor from reactive tissue. 99mTC-sestamibi scans may assist in differentiating neoplastic (99mTC-sestamibi positive) from non-neoplastic tissue (99mTC-sestamibi negative). Previous literature showed sestamibi to be helpful in detecting residual choroid plexus tumors resulting in further resection. Here, we report the first case to show that sestamibi scans can also help with the opposite decision.

Ventricular apparent diffusion coefficient measurements in patients with neoplastic leptomeningeal disease.

BACKGROUND: To test the hypothesis that intraventricular ADC values can be used to determine the presence of neoplastic leptomeningeal disease (LMD). MATERIALS AND METHODS: ADC values were measured at multiple sites in the ventricular system in 32 patients with cytologically-proven LMD and 40 control subjects. Multiple linear regression analysis was used to determine the mean difference of ADCs between the LMD and control groups after adjusting for ventricle size and tumor type. Receiver operating characteristics (ROC) analysis was performed and optimal ADC value cut-off point for predicting the presence of LMD. ADC was compared to T1 enhancement and FLAIR signal hyperintensity for determining the presence of LMD. RESULTS: After adjusting for ventricular volume and tumor type, the mid body of lateral ventricles showed no significant difference in ventricular volume and a significant difference in ADC values between the control and LMD groups (p > 0.05). In the mid-body of the right lateral ventricle the AUC was 0.69 (95% CI 0.57-0.81) with an optimal ADC cut off point of 3.22 × 10- 9 m2/s (sensitivity, specificity; 0.72, 0.68). In the mid-body of left lateral ventricle the AUC was 0.7 (95% CI 0.58-0.82) with an optimal cut-off point of 3.23 × 10- 9 m2/s (0.81, 0.62). Using an average value of HU measurements in the lateral ventricles the AUC was 0.73 (95% CI 0.61-0.84) with an optimal cut off point was 3.11 × 10- 9 m2/s (0.78, 0.65). Compared to the T1 post-contrast series, ADC was predictive of the presence of LMD in the mid-body of the left lateral ventricle (p = 0.036). CONCLUSION: Complex interactions affect ADC measurements in patients with LMD. ADC values in the lateral ventricles may provide non-invasive clues to the presence of LMD.

Phase I study of intraventricular infusions of autologous ex vivo expanded NK cells in children with recurrent medulloblastoma and ependymoma.

BACKGROUND: Recurrent pediatric medulloblastoma and ependymoma have a grim prognosis. We report a first-in-human, phase I study of intraventricular infusions of ex vivo expanded autologous natural killer (NK) cells in these tumors, with correlative studies. METHODS: Twelve patients were enrolled, 9 received protocol therapy up to 3 infusions weekly, in escalating doses from 3 × 106 to 3 × 108 NK cells/m2/infusion, for up to 3 cycles. Cerebrospinal fluid (CSF) was obtained for cellular profile, persistence, and phenotypic analysis of NK cells. Radiomic characterization on pretreatment MRI scans was performed in 7 patients, to develop a non-invasive imaging-based signature. RESULTS: Primary objectives of NK cell harvest, expansion, release, and safety of 112 intraventricular infusions of NK cells were achieved in all 9 patients. There were no dose-limiting toxicities. All patients showed progressive disease (PD), except 1 patient showed stable disease for one month at end of study follow-up. Another patient had transient radiographic response of the intraventricular tumor after 5 infusions of NK cell before progressing to PD. At higher dose levels, NK cells increased in the CSF during treatment with repetitive infusions (mean 11.6-fold). Frequent infusions of NK cells resulted in CSF pleocytosis. Radiomic signatures were profiled in 7 patients, evaluating ability to predict upfront radiographic changes, although they did not attain statistical significance. CONCLUSIONS: This study demonstrated feasibility of production and safety of intraventricular infusions of autologous NK cells. These findings support further investigation of locoregional NK cell infusions in children with brain malignancies.

Imaging and spectroscopic findings in meningioangiomatosis.

Meningioangiomatosis (MA) is an uncommon brain tumor. The role of imaging techniques is underscored in cases where the tumor location makes resection (or even biopsy) dangerous. We report the case of a child with an MA tumor located deep in the right sylvian fissure. A computed tomography (CT) scan showed calcifications in a highly vascular lesion with surrounding edema. Magnetic resonance spectroscopy (MRS) showed a distinct choline (Cho) peak, which usually suggests a proliferating tumor. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed the lesion lacked hypermetabolic features. These radiological features should put MA in the differential diagnosis.

Bilateral gonadoblastoma with dysgerminoma and pilocytic astrocytoma with WT1 GT-IVS9 mutation: A 46 XY phenotypic female with Frasier syndrome.

Frasier syndrome is characterized by a 46 XY disorder of sex development, nephropathy, and increased risk for gonadoblastoma due to Wilms tumor 1(WT1) mutation in the donor splice site of intron-9, resulting in the splice form +KTS. Germ cell tumors and gonadoblastomas have been reported previously in Frasier syndrome. We present the clinical, radiological, and genetic (WT1 mutation analysis) of a 46 XY phenotypic female with Frasier syndrome with bilateral gonadoblastoma with dysgerminoma who developed pilocytic astrocytoma.

RBM10 truncation in astroblastoma in a patient with history of mandibular ameloblastoma: A case report.

Astroblastoma is a rare glial neoplasm composed of cells that have broad processes oriented perpendicular to central vessels and often demonstrate vascular sclerosis. The WHO 2016 classification does not specify a grading system for astroblastoma, and categorizes them as well-differentiated or malignant. These broad classification rubrics, however, do not accurately predict clinical outcome. Genetic profiling of astroblastoma has therefore been of particular interest in the recent years. These efforts, although in small number, have revealed heterogeneous molecular findings that may explain astroblastoma's unpredictable clinical outcome. Here, we report a case of recurrent astroblastoma in a 23-year-old female with a unique molecular characteristic. Our patient's tumor harbored an RNA-binding motif 10 (RBM10) truncation. RBM10 codes for a widely expressed RNA binding protein, and its mutation has been described in a variety of solid cancers. RBM10 is thought to be involved in stabilization of pro-apoptotic proteins in breast cancer, and its reduced protein expression is associated with advanced stages of lung adenocarcinoma. To our knowledge, this is the first report of astroblastoma harboring RBM10 truncation. Interestingly, our patient also has a history of mandibular ameloblastoma, but the link between these two rare tumors is unclear.

A Phase 1/2 Trial of Reirradiation for Diffuse Intrinsic Pontine Glioma.

PURPOSE: To identify an optimal dose for reirradiation (reRT) of diffuse intrinsic pontine glioma. METHODS AND MATERIALS: ReRT dose levels were selected using an adaptive utility-based dose-finding method. The coprimary endpoints were toxicity (mild, moderate, high, or severe) and efficacy, evaluated 1 month after reRT. Efficacy was defined as improvements in imaging, clinical status, and quality of life. Secondary endpoints were progression-free and overall survival. Utility of each dose level was calculated based on a combined toxicity/efficacy score, ranging from 0 for (severe toxicity, no efficacy) to 100 for (mild toxicity, all 3 efficacy improvements). RESULTS: Twelve patients completed reRT at 3 dose levels: 24 Gy in 12 fractions (6 patients), 26.4 Gy in 12 fractions (4 patients), and 30.8 Gy in 14 fractions (2 patients). One patient treated at dose level 3 developed a grade 3 acute toxicity. Five of the 6 patients receiving 24 Gy demonstrated improvement in 2 of 3 efficacy domains, and the sixth demonstrated improvement in all efficacy domains. Of 4 patients receiving 26.4 Gy, 1 demonstrated no improvement, and 1 patient each demonstrated improvement in 1, 2, and 3 efficacy domains. Of 2 patients receiving 30.8 Gy, 1 demonstrated improvement in 3 efficacy domains, and 1 did not complete the quality of life and was not assessed. Mean utilities were 88 for dose level 1, 76 for dose level 2, and 25 for dose level 3. For all patients, the median overall survival was 19.5 months from initial diagnosis (95% confidence interval, 15.6-21.1 months), and the median progression-free survival was 4.5 months from the start of reRT (95% confidence interval, 2.7-6.2 months). CONCLUSIONS: ReRT can safely be delivered for progressive diffuse intrinsic pontine glioma. Clinical improvement was seen in almost all patients. Utility analysis suggests that a regimen of 24 Gy in 12 fractions is preferred.

Increased risk of pseudoprogression among pediatric low-grade glioma patients treated with proton versus photon radiotherapy.

BACKGROUND: Pseudoprogression (PsP) is a recognized phenomenon after radiotherapy (RT) for high-grade glioma but is poorly characterized for low-grade glioma (LGG). We sought to characterize PsP for pediatric LGG patients treated with RT, with particular focus on the role of RT modality using photon-based intensity-modulated RT (IMRT) or proton beam therapy (PBT). METHODS: Serial MRI scans from 83 pediatric LGG patients managed at 2 institutions between 1998 and 2017 were evaluated. PsP was scored when a progressive lesion subsequently decreased or stabilized for at least a year without therapy. RESULTS: Thirty-two patients (39%) were treated with IMRT, and 51 (61%) were treated with PBT. Median RT dose for the cohort was 50.4 Gy(RBE) (range, 45-59.4 Gy[RBE]). PsP was identified in 31 patients (37%), including 8/32 IMRT patients (25%) and 23/51 PBT patients (45%). PBT patients were significantly more likely to have post-RT enlargement (hazard ratio [HR] 2.15, 95% CI: 1.06-4.38, P = 0.048). RT dose >50.4 Gy(RBE) similarly predicted higher rates of PsP (HR 2.61, 95% CI: 1.20-5.68, P = 0.016). Multivariable analysis confirmed the independent effects of RT modality (P = 0.03) and RT dose (P = 0.01) on PsP incidence. Local progression occurred in 10 patients: 7 IMRT patients (22%) and 3 PBT patients (6%), with a trend toward improved local control for PBT patients (HR 0.34, 95% CI: 0.10-1.18, P = 0.099). CONCLUSIONS: These data highlight substantial rates of PsP among pediatric LGG patients, particularly those treated with PBT. PsP should be considered when assessing response to RT in LGG patients within the first year after RT.

Central neurocytoma responsive to topotecan, ifosfamide, carboplatin.

A 5-year-old male presented with spinal cord drop metastasis from a recurrent neurocytoma. Topotecan (0.5 mg/m(2)) and carboplatin (250 mg/m(2)) were administered on days 1-3 and ifosfamide (1,800 mg/m(2)) on days 1-5, every 21 days, for three cycles and resulted in complete response without severe complications. A literature review yielded 20 patients with central neurocytoma but no complete responses. The complete response of central neurocytoma to chemotherapy only reported here should be helpful to those caring for patients with this rare tumor.

Prediction of tumour regrowth of pontine glioma using a two-term model.

BACKGROUND: Modelling tumour regrowth kinetics and determining tumour burden is critically important in making accurate patient prognoses. PATIENTS AND METHODS: Our two-term model, which describes tumour regrowth after chemotherapy was tested by analyzing tumour sizes in patients with pontine gliomas treated at a major cancer centre during the past 40 years. Tumour measurements at four early time points were used to fit the model, which was then used to predict later tumour sizes. The predictions were compared with observed measurements from clinical charts and this model's performance was compared to that of a quadratic model. RESULTS: The mean of relative errors using the two-term model was 0.186; standard deviation, 0.176. For the quadratic model, the mean of relative errors was 0.412; standard deviation, 0.521. CONCLUSION: The two-term model fits the tumour regrowth data reasonably well and is more accurate than a competing quadratic model used in the same way (p < 0.05).