Tumor pseudoprogression and true progression following gamma knife radiosurgery for recurrent ependymoma

BACKGROUND

Gamma knife radiosurgery (GKRS) has become an effective salvage therapeutic option for recurrent ependymomas. However, its effectiveness can be assessed only by neuroimaging before clinical deterioration occurs. We analyzed the evolution of post-GKRS magnetic resonance imaging (MRI) features and sought to establish the feasibility of timely appropriate clinical management of the recurrent tumors.

METHODS

We retrospectively investigated 19 recurrent ependymomas of 11 patients treated with GKRS in our hospital from 1994 to 2013. All included tumors had sequential MRI at 3-6-month intervals, and tumor response was volumetrically calculated on consecutive MRI.

RESULTS

Post-GKRS tumors might show an increased enhancement or loss of enhancement associated with tumor enlargement or straight shrinkage. Seven of 19 tumors (37%) had continuously regressed or remained stable up to the last follow-up. Twelve of 19 tumors (63%) showed enlargement of enhancing lesions through examination of the post-GKRS follow-up MRI within the first 18 months. Five of 12 tumors (42%) showed continuous enlargement, which was interpreted as true progression; seven of 12 (58%) exhibited transient increasing enhanced volume that resolved within 6 months, and which was interpreted as pseudoprogression. There was no significant association between the presence of pseudoprogression and the pathological grades or locations of the tumors, and the concomitant chemotherapy or previous radiotherapy. Statistically significant differences were found for mean apparent diffusion coefficient (ADC) values and ADC ratio (prior to and after GKRS) of enhancing lesions between pseudoprogression and true progression.

CONCLUSION

The MRI patterns of post-GKRS recurrent ependymomas are heterogeneous. Transient increased tumor volume may represent pseudoprogression, whose final tumor control rate was not significantly different from those cases with straight tumor shrinkage. ADC values, ADC ratio, and sequential follow-up MRI scans are beneficial to differentiate between pseudoprogression and true progression, and help guide clinical management.

Anaplastic extramedullary cervical ependymoma with leptomeningeal metastasis

We present a rare extramedullary ependymoma with diffuse spinal metastatic disease, and review the previous reports of extramedullary spinal ependymomas. Ependymomas are the most common intramedullary spinal cord tumor in adults. These tumors rarely present as extramedullary masses. We treated a 23-year-old man with a history of progressive neck, shoulder and arm pain, with sensory and motor symptoms in the C7 dermatome. MRI of the cervical spine demonstrated a ventral contrast-enhancing lesion with evidence of enhancement along the dura and spinal cord of the upper cervical spine, thoracic spine, and cauda equina. He underwent a tumor debulking procedure without complications. Following surgery, he received craniospinal radiation to treat the remaining tumor and diffuse leptomeningeal disease. The final pathology of the tumor revealed that is was a World Health Organization Grade III anaplastic ependymoma. At the 1 year follow-up, the patient had stable imaging and had returned to his preoperative functional status. Of the 19 reported patients with primary intradural, extramedullary spinal ependymomas, two had extradural components and seven had anaplastic grades. Only one tumor with an anaplastic grade resulted in metastatic disease, but without spinal recurrence. To our knowledge, this is the first report of an intradural, extramedullary spinal ependymoma with an anaplastic grade, presenting with concomitant diffuse, nodular leptomeningeal metastasis involving the upper cervical spine, thoracic spine, conus medullaris, and cauda equina. Similar to the treatment of intramedullary ependymomas with metastasis, this patient underwent an aggressive debulking procedure followed by radiation therapy to the entire neuroaxis.

Incidence and dosimetric parameters of pediatric brainstem toxicity following proton therapy

BACKGROUND

Proton therapy offers superior low and intermediate radiation dose distribution compared with photon-based radiation for brain and skull base tumors; yet tissue within and adjacent to the target volume may receive a comparable radiation dose. We investigated the tolerance of the pediatric brainstem to proton therapy and identified prognostic variables.

MATERIAL AND METHODS

All patients < 18 years old with tumors of the brain or skull base treated from 2007 to 2013 were reviewed; 313 who received > 50.4 CGE to the brainstem were included in this study. Brainstem toxicity was graded according to the NCI Common Terminology Criteria for Adverse Events v4.0.

RESULTS

The three most common histologies were ependymoma, craniopharyngioma, and low-grade glioma. Median patient age was 5.9 years (range 0.5-17.9 years) and median prescribed dose was 54 CGE (range 48.6-75.6 CGE). The two-year cumulative incidence of toxicity was 3.8% ± 1.1%. The two-year cumulative incidence of grade 3 + toxicity was 2.1% ± 0.9%. Univariate analysis identified age < 5 years, posterior fossa tumor location and specific dosimetric parameters as factors associated with an increased risk of toxicity.

CONCLUSION

Utilization of current national brainstem dose guidelines is associated with a low risk of brainstem toxicity in pediatric patients. For young patients with posterior fossa tumors, particularly those who undergo aggressive surgery, our data suggest more conservative dosimetric guidelines should be considered.

Role of stereotactic radiosurgery and fractionated stereotactic radiotherapy in the management of intracranial ependymoma

Ependymoma accounts for 5-10% of all childhood CNS tumors and less than 5% of intracranial tumors in adults. Ependymomas typically have a sharp tumor-brain parenchyma interface and this characteristic lends itself well to stereotactic radiation delivery. Data on the use of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for ependymoma in various settings have emerged over the past 10 years. SRS has been used in recurrent disease and as a boost after external beam radiation therapy. FSRT has been used in pediatric brain tumors and can potentially limit the long-term toxicities associated with radiation therapy by reducing the amount of normal brain parenchyma treated. Long-term follow-up is needed to determine the long-term efficacy and toxicities associated with these treatment modalities.

[Surgical seeding of an anaplastic ependymoma]

Ependymomas can relapse at the primary site and disseminate to the spinal cord. Furthermore, extraneural metastases are rare. We present a case of anaplastic ependymoma with extraneural metastasis, possibly caused by surgical seeding. An 18-year-old female was referred to us after experiencing frequent convulsive attacks. At age 9 years, she underwent partial resection of a left frontal anaplastic ependymoma, followed by 45 Gy radiation. At age 15 years, a recurrent tumor was totally removed. Three years later, magnetic resonance images revealed a left frontal recurrent tumor and a new parietal lesion. Our preoperative diagnosis of the parietal tumor was a radiation-induced meningioma. However, intraoperative pathological examinations revealed the lesion to be an anaplastic ependymoma. The tumor, which was located in the epidural space and had invaded extensively into the cranial bone, was gross totally removed. Although extremely rare, surgical seeding of anaplastic ependymomas should be considered as a differential diagnosis for recurrent tumors in the surgical field.

Clinical analysis of primary melanotic ependymoma in the central nervous system: case series and literature review

BACKGROUND

Melanotic ependymoma (ME) is an extremely rare subset of ependymoma characterized by cytoplasmic and extracellular deposition of melanin, with no case series having been reported to date. The aim of this study was to analyze the clinical manifestations, pathological and radiological features, treatment, and follow-up data, and to discuss the diagnosis, management and prognosis of ME.

METHODS

We retrospectively reviewed the clinical and imaging data of six patients with primary ME. The diagnosis was based on radiological and pathological criteria. All the patients were treated surgically with gross total resection. The preoperative and postoperative neurological states of the patients were analyzed. All the follow-up data were obtained from office visits, and the long-term outcomes are presented and discussed.

RESULTS

Patients presented with nonspecific symptoms. On magnetic resonance imaging (MRI), although a characteristic signal variation could be found reflecting the melanin component, individual appearances varied widely and were related to the content and distribution of melanin in the ME lesions. The characteristic ependymoma-related pathological appearance and specific immunostaining for glial fibrillary acidic protein and antimelanoma monoclonal antibody were revealed. During a mean follow-up period of 46.8 months, no local recurrences or distant metastases were observed.

CONCLUSIONS

The accurate diagnosis of ME depends on pathology. The histological grading used for ependymoma can be applied. Most MEs have a relatively benign course. Complete surgical resection alone is the treatment of choice for low-grade MEs, and the outcome may be favorable. Postoperative adjuvant radiotherapy can be considered for lesions with histologically anaplastic features.

Natural history and role of radiation in patients with supratentorial and infratentorial WHO grade II ependymomas: results from a population-based study

Patients with World Health Organization (WHO) grade II supratentorial ependymomas are commonly observed after gross total resection (GTR), although supporting data are limited. We sought to characterize the natural history of such tumors. We used the Surveillance, Epidemiology, and End Results program to identify 112 patients ages 0-77 diagnosed with WHO grade II ependymomas between 1988 and 2007, of whom 63 (56 %) and 49 (44 %) had supratentorial and infratentorial primaries, respectively. Inclusion criteria were strict to ensure patient homogeneity. Of 33 patients with supratentorial tumors after GTR, 18 (55 %) received adjuvant radiation therapy and 15 (45 %) did not. Ependymoma-specific mortality (ESM) was the primary endpoint. With a median follow up of 4.5 years, only 1 of 33 patients with supratentorial ependymoma died of their disease after GTR; the 5-year estimate of ESM in this population was 3.3 % (95 % CI 0.2-14.8 %). Among patients with infratentorial ependymomas after GTR, the 5-year estimate of ESM was 8.7 % (95 % CI 1.4-24.6 %). In patients with subtotally resected tumors, 5-year estimates of ESM in patients with supratentorial and infratentorial primaries were 20.1 % (95 % CI 8.0-36.2 %) and 12.3 % (95 % CI 2.9-28.8 %), respectively. Among the whole cohort, on both univariable and multivariable regression, extent of resection was predictive of ESM, while tumor location and use of radiation were not. After GTR, patients with WHO grade II supratentorial ependymomas have a very favorable natural history with low associated cancer-specific mortality. Observation, with radiation reserved as a salvage option, may be a reasonable postoperative strategy in this population.

Wide-field pulsed reduced dose rate radiotherapy (PRDR) for recurrent ependymoma in pediatric and young adult patients

AIM

This retrospective analysis evaluates feasibility of wide-field re-irradiation using pulsed reduced dose rate (PRDR) technique in patients with recurrent ependymoma. PRDR employs a dose rate of 6 cGy/min, as opposed to 400-600 cGy/min for conventional radiation, allowing for enhanced normal tissue repair.

PATIENTS AND METHODS

Five patients with recurrent ependymoma having eight lesions (two brain, six spinal cord) were treated with PRDR. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan Meier method.

RESULTS

The median interval between two radiation courses was 58 months (range: 32-212 months). The median PRDR dose was 40 Gy (range: 30.6-54 Gy) with a median cumulative lifetime dose of 105.2 Gy (range: 90-162.4 Gy). At a median post-PRDR follow-up of 64 months, estimated 4-year OS and PFS from PRDR was 60% and 35.7%, respectively. None of the patients developed necrosis on serial magnetic resonance imaging scans, and only one patient had progressive mild radiculopathy.

CONCLUSION

In patients with large-volume recurrent ependymoma, re-irradiation with wide-field PRDR is a feasible option.

Infant brain tumors: incidence, survival, and the role of radiation based on Surveillance, Epidemiology, and End Results (SEER) Data

PURPOSE

To evaluate the incidence of infant brain tumors and survival outcomes by disease and treatment variables.

METHODS AND MATERIALS

The Surveillance, Epidemiology, and End Results (SEER) Program November 2008 submission database provided age-adjusted incidence rates and individual case information for primary brain tumors diagnosed between 1973 and 2006 in infants less than 12 months of age.

RESULTS

Between 1973 and 1986, the incidence of infant brain tumors increased from 16 to 40 cases per million (CPM), and from 1986 to 2006, the annual incidence rate averaged 35 CPM. Leading histologies by annual incidence in CPM were gliomas (13.8), medulloblastoma and primitive neuroectodermal tumors (6.6), and ependymomas (3.6). The annual incidence was higher in whites than in blacks (35.0 vs. 21.3 CPM). Infants with low-grade gliomas had the highest observed survival, and those with atypical teratoid rhabdoid tumors (ATRTs) or primary rhabdoid tumors of the brain had the lowest. Between 1979 and 1993, the annual rate of cases treated with radiation within the first 4 months from diagnosis declined from 20.5 CPM to <2 CPM. For infants with medulloblastoma, desmoplastic histology and treatment with both surgery and upfront radiation were associated with improved survival, but on multivariate regression, only combined surgery and radiation remained associated with improved survival, with a hazard ratio for death of 0.17 compared with surgery alone (p = 0.005). For ATRTs, those treated with surgery and upfront radiation had a 12-month survival of 100% compared with 24.4% for those treated with surgery alone (p = 0.016). For ependymomas survival was higher in patients treated in more recent decades (p = 0.001).

CONCLUSION

The incidence of infant brain tumors has been stable since 1986. Survival outcomes varied markedly by histology. For infants with medulloblastoma and ATRTs, improved survival was observed in patients treated with both surgery and early radiation compared with those treated with surgery alone.

[Modern three-dimensional conformal craniospinal radiotherapy]

The main problem of craniospinal irradiation (CSI) is the matching of the fields. The use of a suitable technique is very important because matching of the fields is necessary to use for the optimal cancer irradiation of the long planning target volume (PTV). Since 2007, 8 patients have received CT-based, 3D-planned conformal CSI in our Institute. Patient immobilization was made in prone position in a vacuum bed, using skull and pelvis masks. Organ-at-risk (OAR) contours were made by radiographers. PTV was contoured by radiation oncologists. The prescribed dose to the PTV was 36 Gy with 1.8 Gy dose per fraction. In the planning process the following aspects were taken under consideration: all points of the PTV had to receive at least 95% of the prescribed dose (according to ICRU 50, 62); at junction field edges the overlapping parts were eliminated using a multisegmental technique, where the adjacent segment ends of the neighbouring fields were shifted two times 2 cm, so that the three equally weighted segments used in one field had 2-2 cm distance from each other. In the CSI planning the shape of the patient and so the length of the PTV has made a big emphasis on determining the number of field matching. Thus in some cases instead of two, only one field matching was sufficient - this could be achieved by increasing the source-to-skin distance (SSD) of the fields. The verification made with a solid-water phantom justified the precision of the field matching. The offset used at junction field edges in between one treatment facilitates the verification of field matching - and so the patient positioning. Thus the possibility of having overdosed regions could be reduced, which was very important from a radiation biological point of view.

Recurrent pituitary ependymoma: a complex clinical problem

Ependymomas rarely arise from the region of the pituitary fossa, with only four cases previously reported in the literature. We present a complex case of a recurrent ependymoma of the parasellar region which has been difficult to clinically manage due to its tendency to recurrence. Our patient has had four operations over the last 28 years, with external beam radiotherapy, but still has residual tumor and is currently panhypopituitary and with significant visual loss. We believe there is considerable uncertainty as to the optimal management of any future progression, which seems likely, and are currently considering the use of radiosurgery with careful sparing of the optic chiasm, or possibly the chemotherapeutic agent temozolomide. Our case emphasises the recurrent nature of this rare but difficult tumor.

The management of completely resected childhood intracranial ependymoma: the argument for observation only

INTRODUCTION

The management of children with completely resected intracranial ependymomas is controversial. We favor deferring adjuvant radiotherapy in low-risk patients, whereas others recommend radiotherapy.

REVIEW

This article reviews the available evidence for and against deferring radiotherapy in children with low-risk completely resected childhood ependymomas.

Recurrent paediatric supratentorial extraventricular ependymoma associated with genetic mutation at exon 4 of p53 gene

Recurrent supratentorial extraventricular ependymoma in a four-year-old Malay boy treated twice surgically in combination with cranial radiotherapy is reported. He presented with symptoms of raised intracranial pressure and a history of focal seizure. Computed tomography of the brain showed a left supratentorial extraventricular cystic lesion causing a mass effect. The tumour histology was ependymoma (WHO grade II). The clinical course, radiological characteristics and management of this tumour are discussed. Molecular genetic analysis of p53 and p27 genes revealed substitution of nucleotide G to C at location nucleotide 12139, exon 4 of gene p53. No alteration was detected at exon 5-6 and 8 of p53 gene and exon 1 and 2 of p27 gene.

Intradural tumours of the lumbar spine presenting with low back pain: report of two cases and review of the literature

Two cases of spinal cord tumours (one schwannoma and one ependymoma) of the lumbar spine are reported. The treatment with radical excision and posterolateral fusion, along with adjuvant radiation therapy in the case with ependymoma was successful, with follow-up of six and seven years respectively. A literature review is presented, and a possible presentation with low back pain is analysed.

Proton radiotherapy for childhood ependymoma: initial clinical outcomes and dose comparisons

PURPOSE

To report preliminary clinical outcomes for pediatric patients treated with proton beam radiation for intracranial ependymoma and compare the dose distributions of intensity-modulated radiation therapy with photons (IMRT), three-dimensional conformal proton radiation, and intensity-modulated proton radiation therapy (IMPT) for representative patients.

METHODS AND MATERIALS

All children with intracranial ependymoma confined to the supratentorial or infratentorial brain treated at the Francis H. Burr Proton Facility and Harvard Cyclotron between November 2000 and March 2006 were included in this study. Seventeen patients were treated with protons. Proton, IMRT, and IMPT plans were generated with similar clinical constraints for representative infratentorial and supratentorial ependymoma cases. Tumor and normal tissue dose-volume histograms were calculated and compared.

RESULTS

At a median follow-up of 26 months from the start date of radiation therapy, local control, progression-free survival, and overall survival rates were 86%, 80%, and 89%, respectively. Subtotal resection was significantly associated with decreased local control (p = 0.016). Similar tumor volume coverage was achieved with IMPT, proton therapy, and IMRT. Substantial normal tissue sparing was seen with proton therapy compared with IMRT. Use of IMPT will allow for additional sparing of some critical structures.

CONCLUSIONS

Preliminary disease control with proton therapy compares favorably with the literature. Dosimetric comparisons show the advantage of proton radiation compared with IMRT in the treatment of ependymoma. Further sparing of normal structures appears possible with IMPT. Superior dose distributions were accomplished with fewer beam angles with the use of protons and IMPT.

Intensity-modulated radiation therapy in childhood ependymoma

PURPOSE

To determine the patterns of failure after intensity-modulated radiation therapy (IMRT) for localized intracranial ependymoma.

METHODS AND MATERIALS

From 1994 to 2005, 22 children with pathologically proven, localized, intracranial ependymoma were treated with adjuvant IMRT. Of the patients, 12 (55%) had an infratentorial tumor and 14 (64%) had anaplastic histology. Five patients had a subtotal resection (STR), as evidenced by postoperative magnetic resonance imaging. The clinical target volume encompassed the tumor bed and any residual disease plus margin (median dose 54 Gy). Median follow-up for surviving patients was 39.8 months.

RESULTS

The 3-year overall survival rate was 87% +/- 9%. The 3-year local control rate was 68% +/- 12%. There were six local recurrences, all in the high-dose region of the treatment field. Median time to recurrence was 21.7 months. Of the 5 STR patients, 4 experienced recurrence and 3 died. Patients with a gross total resection had significantly better local control (p = 0.024) and overall survival (p = 0.008) than those with an STR. At last follow-up, no patient had developed visual loss, brain necrosis, myelitis, or a second malignancy.

CONCLUSIONS

Treatment with IMRT provides local control and survival rates comparable with those in historic publications using larger treatment volumes. All failures were within the high-dose region, suggesting that IMRT does not diminish local control. The degree of surgical resection was shown to be significant for local control and survival.

Image-Guided Intensity-Modulated Photon Radiotherapy Using Multifractionated Regimen to Paraspinal Chordomas and Rare Sarcomas

PURPOSE

Image-guided intensity-modulated radiotherapy enables delivery of high-dose radiation to tumors close to the spinal cord. We report our experience with multifractionated regimens using image-guided intensity-modulated radiotherapy to treat gross paraspinal disease to doses beyond cord tolerance.

METHODS AND MATERIALS

We performed a retrospective review of 27 consecutive patients with partially resected or unresectable paraspinal tumors irradiated to >5,300 cGy in standard fractionation.

RESULTS

The median follow-up was 17.4 months (range, 2.1-47.3). Eighteen sarcomas, seven chordomas, and two ependymomas were treated. The median dose to the planning target volume was 6,600 cGy (range, 5,396-7,080) in 180- or 200-cGy fractions. The median planning target volume was 164 cm3 (range, 29-1,116). Seven patients developed recurrence at the treatment site (26%), and 6 of these patients had high-grade tumors. Three patients with recurrence had metastatic disease at the time of radiotherapy. The 2-year local control rate was 65%, and the 2-year overall survival rate was 79%. Of the 5 patients who died, 4 had metastatic disease at death. Twenty-three patients (84%) reported either no pain or improved pain at the last follow-up visit. Sixteen patients discontinued narcotic use after treatment (62.5%). Twenty-three patients (89%) had a stable or improved American Spine Injury Association score at the last follow-up visit. No patient experienced radiation-induced myelopathy.

CONCLUSIONS

The dose to paraspinal tumors has traditionally been limited to respect cord tolerance. With image-guided intensity-modulated radiotherapy, greater doses of radiation delivered in multiple fractions can be prescribed with excellent target coverage, effective palliation, and acceptable toxicity and local control.

Childhood intracranial ependymoma: twenty-year experience from a single institution

BACKGROUND

Because few large studies of pediatric ependymoma treatment are available, the authors believed that a retrospective review of treatment outcomes from a single institution would yield potentially valuable information regarding potential prognostic factors. In this article, they report their 20-year institutional experience with this disease.

METHODS

Medical records were reviews of patients with intracranial ependymoma who received their initial treatment at the Children's Hospital of Philadelphia (CHOP)/Hospital of the University of Pennsylvania (HUP) between January 1980 and December 2000. Of the 61 patients who were identified, 49 patients underwent primary therapy at CHOP/HUP and formed the basis for the study. Actuarial overall survival (OS) and progression-free survival (PFS) were determined by the Kaplan-Meier method. Univariate and multivariate analyses were performed using the log-rank test and Cox proportional-hazards models.

RESULTS

With median follow-up of 110.2 months, the 5-year OS and PFS rates were 66.2% and 40.7%, respectively. Older age and higher radiation dose significantly predicted for improved OS. Anaplastic histology predicted for decreased PFS. Cervical spinal cord extension resulted in decreased OS primarily caused by failures outside the primary site. Patients who had a favorable prognosis (aged >/=3 years, no dissemination or cord extension, complete resection, and radiation dose >/=54 grays [Gy]) had 5-year OS and PFS rates of 83.1% and 60.6%, respectively.

CONCLUSIONS

In this study of patients with pediatric intracranial ependymoma, OS and PFS rates were concordant with the rates published in other modern series. The finding of a dose response up to 54 Gy supported the current trend toward dose escalation. Tumor extension to the cervical spine was identified as a predictor for failure outside of the primary site. Although the survival rates were encouraging, there is still significant room for improvement in the management of this disease.

Outcomes in treatment for intradural spinal cord ependymomas

PURPOSE

Spinal cord ependymomas are rare tumors, accounting for <2% of all primary central nervous system tumors. This study assessed the treatment outcomes for patients diagnosed with spinal cord ependymomas within the Southern California Kaiser Permanente system.

METHODS AND MATERIALS

We studied 23 patients treated with surgery with or without external beam radiotherapy (EBRT). The local and distant control rates and overall survival rates were determined.

RESULTS

The overall local control, overall recurrence, and 9-year overall survival rate was 96%, 17.4%, and 63.9%, respectively.

CONCLUSIONS

The results of our study indicate that en bloc gross total resection should be the initial treatment, with radiotherapy reserved primarily for postoperative cases with unfavorable characteristics such as residual tumor, anaplastic histologic features, or piecemeal resection. Excellent local control and overall survival rates can be achieved using modern microsurgical techniques, with or without local radiotherapy.

Tympanic Membrane Breakdown After Intratympanic Injection of Steroids in Irradiated Ears

OBJECTIVE

To describe a rare complication of intratympanic injection of steroids in susceptible ears.

PATIENTS

We present two patients with a history of irradiation involving the injected ear.

INTERVENTION

Therapeutic.

MAIN OUTCOME MEASURE

Tympanic membrane condition after intratympanic injection of steroids.

RESULTS

Total or near-total breakdown of the irradiated tympanic membrane.

CONCLUSION

Tympanic membranes with an impaired wound-healing ability, together with exposure to intratympanic steroids, may be at risk for total or near-total breakdown.