Radiation therapy has long been a mainstay in the treatment of ependymoma. Concerns about the long-term effects of radiation therapy have made many parents and caregivers wary of this treatment modality. However, with the advent of conformal radiation and evidence
Radiation therapy has long been a mainstay in the treatment of ependymoma. Concerns about the long-term effects of radiation therapy have made many parents and caregivers wary of this treatment modality. However, with the advent of conformal radiation and evidence supporting its use in younger children (ie, < 3 years old), the standard of care for childhood ependymoma is rapidly evolving to include immediate postoperative radiation therapy for all pediatric patients. The role of chemotherapy in the treatment of ependymoma has diminished recently because (1) chemotherapy fails to delay radiation therapy for a meaningful period of time; (2) tumors that progress during chemotherapy do not respond as well to subsequent irradiation; and (3) the combination of chemotherapy and irradiation does not improve overall survival. However, chemotherapy may make residual tumor more amenable to a second resection. Fewer than 50% of pediatric patients with ependymoma undergo complete resection before receiving radiation therapy. Because the extent of resection is one of the most important prognostic factors in the treatment of this disease, increasing the rate of complete resections is a significant means of increasing long-term survival. By incorporating current concepts of ependymoma, a more uniform approach to the treatment of this disease can be developed. In addition, by combining the best available means of detecting and managing side effects, the future for pediatric patients with ependymoma remains optimistic. This review presents historical and current practices used to treat ependymoma, and is intended to provide an information framework for caregivers so that they can assist parents in the decision-making process. [ONCOLOGY 16:629-648, 2002]
Ependymoma accounts for 8% to 10% of all childhood central nervous system (CNS) tumors, with fewer than 170 new cases diagnosed annually in the United States in children and adults younger than 25 years old. The mean age at the time of diagnosis ranges from 51 to 71 months,[2-5] and 25% to 40% of those diagnosed are younger than age 3. Survival statistics for ependymoma are generally disappointing: The historical 5-year survival estimate is 50% to 64%, and the historical progression-free survival estimate is 23% to 45%.[2,4,7-9] Recurrences are typically local, and the median time to recurrence is 13 to 25 months.[2-4,7,9,10] Approximately 20% of failures involve distant recurrence, and late recurrences are not uncommon.
Ependymoma develops from the neuroepithelial lining of the ventricles of the brain and the central canal of the spinal cord; 90% of tumors are located intracranially, with 30% occurring above the tentorium and 60% below it (Figure 1). Supratentorial ependymoma arises either from the lateral or third ventricle (60%) or from the cerebral hemisphere (40%).[1,11] Infratentorial ependymoma arises from one of three specific sites within the fourth ventricle: the floor (60%), the lateral aspect (30%), or the roof (10%).[12,13] Tumors that arise from the floor of the fourth ventricle may extend through the foramen of Magendie and over the dorsal surface of the spinal cord. Those that arise from the lateral aspect of the fourth ventricle can extend out of the foramen of Luschka and into the cerebellopontine angle and along the anterior aspect of the pons and medulla (Figure 2).
Complete surgical removal of posterior fossa ependymoma arising from the floor or lateral aspect of the fourth ventricle is difficult because these tumors are typically close to the surface of the brainstem and cranial nerves. Fortunately, neuraxis dissemination at the time of diagnosis is rare and occurs in fewer than 7% of patients (Figure 3).
Numerous studies have sought to identify prognostic factors for intracranial ependymoma; most have been single-institution, retrospective reports that span several decades and consequently include numerous advances in neuroimaging, neurosurgery, radiation oncology, chemotherapy, and supportive measures. Surgical resection appears to be the most important prognostic factor.[2-5,7-11,14] In patients with completely resected tumors, the 5-year survival estimate is 67% to 80% and the 5-year progression-free survival estimate is 51% to 75%. Among patients with incompletely resected tumors, the 5-year survival estimate is 22% to 47%, and the 5-year progression-free survival estimate is 0% to 26% (Figure 4).
Age at Diagnosis
Age, at the time of diagnosis, may also be an important prognostic factor. Very young children typically have a poorer outcome.[4,7,15] For children younger than 3 years old at diagnosis, Pollack et al reported a 5-year survival estimate of 22% and a progression-free survival estimate of 12%. In older children, the 5-year survival estimate is 75%, and the progression-free survival estimate is 60%.
Duffner et al reported the experience of the Pediatric Oncology Group (POG) in very young children. For children who were younger than age 3 and had undergone gross total resection, they calculated a 5-year survival rate of 61%, whereas for those who had undergone subtotal resection, the estimate was 30%. The POG study also showed a 63% 5-year survival for young children (aged 24 to 35 months) in whom radiation therapy was delayed for 1 year, but a 26% 5-year survival for infants and very young children (aged 0 to 23 months) in whom radiation therapy was delayed for 2 years. The POG findings suggest that the poor survival estimates frequently reported for very young children are most likely related to the higher incidence of infratentorial tumors, the lower rate of complete resection, and the delay in the administration of radiation therapy.
Historic studies have shown that patients with ependymoma who receive radiation therapy experience a better outcome than those who are not treated with irradiation.[17,18] In addition, one study suggested that the improvement in outcome may be radiation dose-dependent (ie, higher doses may improve outcome). However, no randomized trials have unequivocally demonstrated that improved outcome is caused solely by radiation therapy; other factors such as extent of resection and age at the time of diagnosis also contribute to the outcome.
Histologic Grade of the Tumor
One of the most controversial prognostic factors in childhood ependymoma is the histologic grade of the tumor. Although numerous reports have suggested that patients with differentiated ependymoma achieve a better outcome than do those with anaplastic ependymoma,[11,17,20-25] some investigators believe that histologic grade has no prognostic significance.
We recently reported histologic characterization of tumors and outcome in a contemporary series of 50 patients. In a blinded review of pathology, we determined that histologic grade was significantly related to progression-free survival after irradiation (P < .001). The 2-year event-free survival estimate (± SE) was 32% ± 14% for patients with anaplastic ependymoma and 84% ± 7% for patients with differentiated ependymoma. Statistical significance was maintained when the analysis was adjusted for age (< 3 years), chemotherapy with or without tumor progression before radiation therapy, and extent of resection.
The finding of a poor progression-free survival estimate after irradiation for patients with anaplastic ependymoma parallels the findings from other contemporary series.[19,24] Data from the blinded pathology review at St. Jude also showed that anaplastic ependymoma was more likely to occur in the supratentorial brain (P = .002). Of 12 patients with supratentorial tumor, 6 experienced a recurrence despite gross total resection and irradiation.
Histologic evaluation plays an important role in the design and interpretation of prospective trials and in determining the significance of prognostic factors in the current treatment era (Figure 5). Cooperative multi-institutional protocols will enable us to determine the significance of the various factors that will be used to estimate prognosis and stratify individual treatments.
The standard of care for ependymoma is maximal surgical resection with an acceptable neurologic outcome followed by postoperative radiation therapy directed at the site of the primary tumor. Immediate postoperative irradiation is not a widely accepted practice in the treatment of children younger than age 3; multiagent chemotherapy has typically been administered in an effort to delay or avoid irradiation. However, an obvious role for chemotherapy has not been demonstrated for patients with ependymoma, especially those older than age 3. The poor outcome of children younger than age 3 has been attributed in part to the delay in administering radiation therapy. Therefore, the approach for this very young group of patients with ependymoma should be reevaluated in light of recent advances in radiation therapy.
Ependymoma is a relatively slow-growing tumor with a propensity for local invasion. Subarachnoid dissemination is rare and considered incurable. Because the predominant pattern of failure for ependymoma is local, aggressive measures of local control are essential. Several institutional retrospective reviews[2-5,7,8,10,11] and two prospective phase III trials[9,16] have shown that the extent of surgical resection is the most consistent prognostic factor for patients with ependymoma.
Sutton et al retrospectively evaluated 45 patients with ependymoma and found that the 5-year survival estimate after total or near total resection was 60%; the 5-year survival estimate after subtotal resection (defined as < 90% tumor resection) was 21%. In a similar retrospective review of 40 patients, Pollack et al found that 5-year survival after gross total resection was 80%; after partial resection (ie, less than gross total resection), it was 22%.
Perilongo et al retrospectively evaluated 92 children with ependymoma who participated in the Italian Pediatric Neuro-Oncology Group. For patients who had undergone gross total resection, the 10-year survival estimate was 70%, and the progression-free survival estimate was 57%; for patients who had undergone subtotal resection, the 10-year survival estimate was 32%, and the 10-year progression-free survival estimate was 11%. Finally, Robertson et al prospectively treated 32 patients in the Children’s Cancer Group (CCG) Protocol 921. They found that the 5-year progression-free survival was 66% for patients with residual tumor measuring 1.5 cm², and 11% for those with residual tumors measuring more than 1.5 cm².
Successful treatment of newly diagnosed or recurrent intracranial ependymoma by resection alone has been reported by two independent groups.[26,27] Hukin et al reported 10 pediatric cases in which gross total resection was the only initial therapy for intracranial ependymoma (eight supratentorial tumors and two posterior fossa tumors). At a median follow-up of 48 months, seven patients were free of disease without further intervention, and three patients experienced tumor recurrence at 9, 10, and 20 months after resection. Two patients with recurrence were effectively treated with an additional surgical procedure and postoperative radiation therapy.
Palma et al reported on their success in treating supratentorial ependymoma with surgery alone. Of 12 surviving patients, 6 in their original series of 23 patients were treated with surgery alone, and only 1 experienced a recurrence after 10 years of follow-up. These findings indicate that some patients with intracranial ependymoma-probably those with supratentorial tumors-require resection only. Thus, radiation therapy and its potential for late effects might be delayed until the time of recurrence for a very select group of patients.
Although complete resection is instrumental in the long-term, event-free, and overall survival of patients with childhood ependymoma, it is performed in only 42% to 62% of patients.[4,5,7,8] Complete resection is more easily accomplished for tumors in supratentorial locations and those originating from the roof of the fourth ventricle. Aggressive attempts to resect tumors in other locations, including those involving the lower cranial nerves, are associated with increased morbidity.
Despite the high rate of incomplete initial resections, few studies have included a second surgical procedure for patients with residual disease.[28,29] The timing of a second resection is the subject of debate: Some oncologists favor the use of chemotherapy between the initial and second resections.
The purpose of administering chemotherapy before a second resection is to make the tumor more amenable to resection and to prevent tumor progression during the interval between procedures. Foreman et al reported second resections in five patients with residual tumors located in the fourth ventricle. One patient underwent an immediate second-look procedure, and the other four received short courses of chemotherapy before a second-look procedure. Gross total resection was achieved with the second procedure in four of the five patients. No severe morbidity was reported after the second resection; three of the patients remained progression-free at 23, 25, and 34 months after the second procedure and postoperative radiation therapy.
From April 1997 through April 2000, 40 pediatric patients were referred to St. Jude Children’s Research Hospital for treatment of intracranial ependymoma; 24 patients (60%) underwent complete resection, and 16 (40%) had residual tumor after their initial procedure and prior to referral. Of those 16, 12 were considered candidates for additional resection based on the location of the residual tumor and neurologic status at the time of evaluation.
A complete resection was performed in 10 patients and a near total resection in 2 patients with the second procedure. By combining the number of patients with a complete resection after their initial procedure with the number of those with complete resection after a second procedure, we increased the group’s rate of complete resection to 85% (Figure 6).
The operative morbidity of these patients was also determined. Significant morbidity, defined as lower cranial neuropathy necessitating gastrostomy or tracheostomy, occurred in 4 of the 24 patients with initial complete resections and 4 of the 16 patients with initial incomplete resections. Significant morbidity occurred in only one patient who underwent a second resection. Of the 12 patients who underwent a second resection, 6 had tumors that progressed during the interval between surgical procedures, despite administration of chemotherapy.
It is generally agreed that a complete resection-ie, one that results in a very low probability of leaving even microscopic residual tumor-is rarely achieved in ependymoma. Complete resection may be possible for patients with supratentorial tumors when a margin of normal tissue surrounding the tumor is also removed and biopsies of the operative cavity are negative. Biopsies of the operative cavity are seldom performed; however, such biopsies could be therapeutically beneficial and could contribute to the planning of radiation treatment.
Current management of childhood ependymoma relies on three principal classifications of resection (Figure 7 and Table 1). A resection is classified as a gross total procedure when either no visible tumor or only microscopic tumor is identified with the operating microscope after resection, and no evidence of disease is identified in postoperative neuroimaging studies. Although the classification of near total resection has not been adequately defined, it generally includes patients with minimal residual tumor for whom a second resection would produce no benefit. For this reason, such patients are often treated in the same manner as those who have undergone gross total resection.
In the current management of childhood ependymoma, a resection is classified as near total when minimal residual tumor is present. For purposes of future studies, this could be an area on a single image (< 1.5 cm²), a single greatest dimension on a single image (< 5 mm), or a volume (to be determined). A resection is classified as subtotal, or incomplete, when macroscopically visible tumor is identified with the operating microscope after resection, and residual tumor larger than that used to define near total resection is present on postoperative neuroimaging studies.
For nearly 20 years, the avoidance of radiation therapy has been the hallmark of trial designs for the treatment of brain tumors in young children. Strategies that either delay or avoid irradiation have been justified on the basis of concerns about the effects of irradiation on neurologic, endocrine, and cognitive functions. Although irradiation-induced deficits have not been well documented in cases of childhood ependymoma, this therapy has, in the past, paralleled that used for other more common childhood tumors such as medulloblastoma (the effects of which have been well documented). Since 1977, postoperative radiation therapy has been considered standard treatment for patients with ependymoma.
Mork et al were the first to demonstrate that postoperative radiation therapy improves outcome in ependymoma patients. These investigators reported a survival estimate of 17% for patients who underwent resection alone vs a 40% survival estimate for those who underwent resection and postoperative irradiation. Radiation therapy has been routinely administered to patients with ependymoma who are 3 years of age or older, but, as yet, no studies have critically challenged its role in the postoperative treatment of patients in this age group.
On the other hand, the role of radiation therapy has been evaluated in several studies in infants and children younger than age 3, including the POG 8633 study. This study showed that young children with completely resected ependymoma in whom radiation therapy was delayed for 2 years experienced a significantly worse outcome (5-year survival estimate: 38%) than those in whom therapy was delayed for 1 year (5-year survival estimate: 88%). This finding supports the use of radiation therapy and contradicts the policy of delaying treatment for the time intervals specified in the study.
Although a better event-free survival may be achieved in patients who have undergone complete resection, the volume of residual tumor in those undergoing incomplete resection may be smaller in this advanced neurosurgical era than it was in prior treatment eras. Indeed, more recent findings suggest that a contemporary incomplete resection differs considerably from one achieved with the technology available more than a decade ago.[25,30] Five-year progression-free survival estimates as low as 0% to 26% have been reported in patients with macroscopic residual tumor after surgery, despite the use of radiation therapy.[2,5,7,8,14] Of course, the neurosurgical era from which these findings were derived should be taken into account.
Optimal Radiation Dose and Volume
The optimal dose of radiation remains unclear. The evaluation of a dose-response relationship for a given type of tumor requires prospective evaluation. Retrospectively, an increase in the dose of radiation administered to the primary site appears to improve local control.[18,19]
The recent POG 9132 study used hyperfractionated radiation therapy delivered to the primary site at a total dose of 6,960 cGy for the treatment of posterior fossa ependymoma. The investigators found that 19 patients who underwent subtotal resection had a better outcome (4-year event-free survival: 50%) than did a comparable group of patients who participated in the earlier POG 8532 study, which used a lower total dose of conventional radiation (4-year event-free survival: 24%). Hyperfractionated radiation therapy did not improve survival estimates in patients with completely resected tumors. In addition, several retrospective studies have failed to demonstrate any benefits associated with the use of prophylactic craniospinal irradiation.[4,13,19,32]
Conformal radiation therapy limits the highest doses to the primary site and decreases the dose received by normal tissues. Reducing the dose received by normal tissues is logical in children, but requires systematic definition of the treatment volume and prospective study to determine that irradiation using more limited volumes does not increase the risk of marginal treatment failures.
We recently reported the preliminary results of a St. Jude protocol (RT-1) in which 64 pediatric patients with localized ependymoma received treatment between July 1997 and October 2000. An anatomically defined, clinical target volume margin of 10 mm surrounding the postoperative residual tumor and tumor bed was used. Only six failures occurred after a median follow-up of 17 months (range: 3 to 43 months) in the group of patients with a median age of 2.9 years (range: 1.1 to 21 years). With the exception of one patient who developed metastatic disease with no evidence of local failure, failures at the primary site were encompassed by the prescription isodose. Most patients received a total radiation dose of 59.4 Gy. These preliminary results demonstrate that the volume of irradiation can be substantially reduced without compromising disease control in pediatric patients with ependymoma.
Reducing the volume of irradiation will only be beneficial if the rate of disease control remains the same and the incidence of side effects decreases. Several reports have compared outcomes in terms of disease control, but few investigations of functional outcome have been unbiased regarding radiation therapy. Pediatric patients have never been systematically evaluated for side effects before undergoing radiation therapy; thus, the side effects reported for these studies include those caused by the tumor, resection, radiation therapy, and possibly other therapies including chemotherapy.
A trial that compares conventional radiation therapy with conformal radiation therapy will never be performed because the dosimetric advantages of the newer treatment are obvious. Investigations that include careful evaluations performed before and after irradiation will be necessary to understand the effects of radiation dose and volume on functional outcome in pediatric patients (Figure 8).
At St. Jude, patients with localized primary brain tumors such as ependymoma that require only focal irradiation are serially evaluated for evidence of CNS effects before and after radiation therapy. Before irradiation, morbidity in this group is high; nearly 50% of those with posterior fossa tumors show evidence of endocrinopathy, as determined by dynamic tests of endocrine function. The most common endocrinopathies include growth hormone deficiency, thyroid hormone deficiency, and adrenal insufficiency. Preirradiation morbidity has also been assessed by cognitive and neurologic measures in this patient population. Low-average IQ (90 ± 17) and higher hearing thresholds (~20 to 25 dB HL) have been observed for children with ependymoma prospectively evaluated prior to radiation therapy.
During the development of conformal treatment plans, normal tissue structures should be contoured and the dose determined for that volume. These measures will provide valuable information that can be used to examine the effects of radiation dose and volume on the function of healthy tissue. For example, the integral dose and volume for the temporal lobe may be correlated with neuropsychometric measures, whereas the integral dose and volume for the hypothalamus may be correlated with evidence of endocrinopathy (Figure 9).
Assessing the effects of radiation dose and volume requires baseline and serial evaluation after irradiation, evidence of effect and observation for a period of time during which the effect is likely to be observed. Using integrated three-dimensional dosimetry, we recently demonstrated the effects of low and high-dose hypothalamic irradiation on the time course of growth hormone deficiency up to 12 months after irradiation. Such information may be used a priori to optimize treatment planning and predict outcome. In assessing cognitive outcomes after conformal radiation therapy, we have not observed a decline in IQ estimates during the first 30 months after treatment; this finding holds for the youngest children (age < 6 years) with infratentorial tumors treated to 59.4 Gy. The need for additional follow-up notwithstanding, this group is faring markedly better than comparably aged patients treated for medulloblastoma.[38,39]
Recurrence after conformal radiation therapy should also be evaluated in terms of dose and volume received. By comparing these measures with neuroimaging studies performed at the time of failure, we can determine the pattern of failure (Figure 10).
Several retrospective reviews have assessed the effectiveness of chemotherapy in the treatment of newly diagnosed ependymoma, and none have found that it improves overall survival.[2-5,7,19,40] The CCG 942 study is the only randomized trial that compared survival after irradiation alone with survival after irradiation and chemotherapy in pediatric patients (aged 2 to 16 years) with ependymoma. The investigators concluded that adjuvant chemotherapy with lomustine (CeeNu), vincristine, and prednisone did not improve outcome. The CCG 921 study, a prospective randomized study of radiation therapy followed by either lomustine, vincristine, and prednisone or a combination of agents known as "8 in 1" (ie, eight drugs in 1 day), used survival analyses to demonstrate that the outcome of patients who received chemotherapy was no better than that of historical controls.
Adjuvant Combination Chemotherapy
Ependymoma does respond to some chemotherapeutic regimens. However, the findings of single-agent phase II studies of recurrent ependymoma have been disappointing. Cisplatin has produced one of the highest response rates (30%) of all agents used to treat recurrent ependymoma. Recent reports of adjuvant combination chemotherapy in pediatric patients with newly diagnosed ependymoma have demonstrated encouraging responses without improving survival, suggesting a limited role.
For example, White et al reported an 86% response rate to four cycles of vincristine, etoposide, and cyclophosphamide (Cytoxan, Neosar) in seven children younger than age 4 who had been newly diagnosed. Duffner et al achieved a 48% response rate with two cycles of vincristine and cyclophosphamide administered to 25 infants and children younger than age 3. Mason et al reported a 16% response rate to four or five cycles of cisplatin, vincristine, etoposide, and cyclophosphamide in 10 children younger than age 6. Fouladi et al demonstrated a 33% response rate with two cycles of ifosfamide (Ifex), etoposide, and carboplatin (Paraplatin) in six children with newly diagnosed ependymoma.
A recent prospective study by Needle et al used irradiation followed by carboplatin and vincristine alternating with ifosfamide and etoposide in patients older than 36 months with newly diagnosed ependymoma. The 5-year progression-free survival estimates of the 10 patients with incompletely resected tumors was 80%. These excellent survival statistics for patients with incompletely resected ependymoma suggested that chemotherapy may be beneficial. However, it cannot be determined if their favorable outcome was related to the volume of residual tumor, radiation therapy, or histology. Unfortunately, radiation therapy was not standardized in this study; the fact that a portion of the patients received hyperfractionated radiation therapy confounds the analysis of the results.
Standard vs Dose-Intensive Chemotherapy
The POG 9233 study compared standard chemotherapy (six 12-week cycles of cisplatin, cyclophosphamide, etoposide, and vincristine) and dose-intensive chemotherapy (eight 9-week cycles of the same agents with differences in relative intensity) in a group of infants with brain tumors including ependymoma. Event-free survival estimates were significantly increased for patients with ependymoma treated with dose-intensive chemotherapy, yet there was no difference in overall survival estimates. The relative dose intensities (compared with standard doses) were 1.67 for cisplatin, 2.67 for cyclophosphamide, 1.54 for etoposide, and 1.33 for vincristine.
Grill et al recently reported the results of a French Society of Pediatric Oncology trial in 73 children treated with multiagent chemotherapy for 16 to 18 months after maximal resection. Irradiation was not included in the treatment regimen. Progression-free survival estimates at 2 and 4 years were 33% and 22%, respectively, with 50% of patients relapsing during the planned chemotherapy course. Salvage therapy included additional surgery, radiation therapy, and for some, high-dose chemotherapy. Overall survival for the entire group was approximately 52% at 5 years and for the patients who relapsed, 49% at 2 years after relapse. As expected, supratentorial tumors and children with complete resection fared better; 23% were alive at 4 years without irradiation.
Chemotherapy and Second Resection
Chemotherapy may make residual tumors more amenable to complete surgical resection. Foreman et al used chemotherapy between the initial and second resections in four patients with ependymoma. After chemotherapy, all the patients had viable tumor; complete resections were performed in three of the four, all of whom remained progression-free at 23 to 34 months after second-look surgery. The subjective impression of the investigators was that the tumors were better defined and easier to dissect after chemotherapy.
Platinum-based therapy has produced the best results in studies with limited numbers of patients. Response rates as high as 67% were reported in a recent review by Gornet. Carboplatin and etoposide are frequently used because they can penetrate the CNS. Results suggest that some neoplasms, particularly slower-growing tumors, respond better with prolonged exposure to chemotherapeutic agents. Needle et al demonstrated the effectiveness of treatment with oral etoposide in five patients with ependymoma; two patients responded, including one who achieved a complete response (Figure 11).
Future Role of Chemotherapy
Chemotherapy may serve four important functions in the future: Such treatment may be used (1) to bridge the interval necessary while planning a second resection; (2) to make the tumor more amenable to resection and improve the rate of complete resection at the time of the second procedure; (3) to reduce the morbidity of the second resection; and (4) bridge the interval required to prepare a child who has suffered neurologic complications from tumor or surgery for daily radiation therapy and often anesthesia.
The selection of the best agents, the schedule of delivery, and the duration of chemotherapy necessary to achieve these goals are difficult to determine given the range of responses, the differences in toxicity profiles, and the lack of data from which to model such a study. Most investigators prefer to use combinations of drugs including carboplatin or cisplatin, etoposide, cyclophosphamide, and vincristine. Concerns about the use of carboplatin, which has a better toxicity profile, persist among investigators because this agent’s equivalency to cisplatin has not been demonstrated.
The findings of Gaynon et al support the use of carboplatin for patients with ependymoma. These researchers found a 40% overall response rate for patients with ependymoma who had not been previously treated with cisplatin. One of the principal reasons for using carboplatin is to avoid ototoxicity. Although one or two courses of cisplatin may be relatively less ototoxic than a longer or more conventional course of the agent, the risk of substantial and permanent hearing loss increases linearly with each dose. In addition, substantial concerns about hearing loss arise for patients who receive cisplatin and radiation therapy.
A national treatment standard for all pediatric patients with intracranial ependymoma is needed. Opinions about what that standard should be are varied, despite an apparent consensus among the members of cooperative groups that a national study using a conformal radiation therapy regimen similar to that tested at St. Jude should be initiated.
Ependymoma is a rare tumor and, with few exceptions, is rarely seen by pediatric oncologists. Therefore, only multi-institution studies conducted by a cooperative group such as the Children’s Oncology Group can lead to improvements in outcome for children with ependymoma.
Local control is the primary treatment objective because local recurrence is the predominant mode of failure. The local failure rate is highest among patients who have undergone incomplete resection (despite postoperative radiation therapy), and contemporary chemotherapy does not improve overall survival. However, marked advances have been made in neurosurgical technique and radiation technology. These advances should significantly improve the outcome of patients with childhood ependymoma by increasing the rate of complete resection without added morbidity and by reducing or eliminating side effects attributable to radiation therapy. In addition, potentially important prognostic variables such as age, histologic characteristics, and location of primary tumor need to be evaluated in the context of a contemporary clinical trial.
The availability of neurosurgeons and radiation oncologists with the expertise to treat pediatric ependymoma patients varies among institutions. Through the design and implementation of a multicenter treatment trial, we could increase the rate of complete resection and systematically deliver radiation therapy that is safe and effective. We could also develop a standard approach to assist caregivers who are less familiar with the treatment of this rare disease.
The proposed schema of the next Children’s Oncology Group study to further investigate the current management of childhood ependymoma in a multi-institutional cooperative trial is diagrammed in Figure 12. We plan to administer a 7-week course of chemotherapy that consists of carboplatin, cyclophosphamide, etoposide, and vincristine to patients who have undergone incomplete resection before a second surgical procedure is performed. The trial will also include conformal radiation therapy for all patients with ependymoma (maximal dose: 59.4 Gy; clinical target volume: 1.0 cm), and an observational study of pediatric patients who have undergone complete resection of supratentorial, differentiated ependymoma. Observation has not been suggested for supratentorial anaplastic tumors based on the St. Jude data.
Immediate postoperative conformal radiation therapy is recommended for the treatment of childhood ependymoma on the basis of the following criteria:
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