Pre-irradiation chemotherapy for infants and children with medulloblastoma: a preliminary report

Childhood medulloblastoma: current status of biology and treatment

Medulloblastoma, a primitive neuro-ectodermal tumour that arises in the posterior fossa, is the most common malignant brain tumour occurring in childhood. Over the past half century, the long-term survival for children with medulloblastoma has improved remarkably from a certain fatal diagnosis to a cancer that is often curable. Although overall survival for children with non-disseminated and non-anaplastic medulloblastoma can approach 80%, the current multidisciplinary therapeutic approach is not without long-term sequelae. Chemotherapy has improved the long-term survival and allowed for reductions in the amount of radiation given, thereby reducing some of the long-term toxicities. In this review, we describe the current understanding of the basic biology of medulloblastoma and report on the current active chemotherapeutic agents utilized in medulloblastoma therapy. Ultimately, our understanding of the basic biology of medulloblastoma may lead to further advances in therapy by providing targets that are more specific and potentially less toxic.

Molecular pathogenesis of adult brain tumors and the role of stem cells

Primary brain tumors consist of neoplasms with varied molecular defects, morphologic phenotypes, and clinical outcomes. The genetic and signaling abnormalities involved in tumor initiation and progression of the most prevalent adult primary brain tumors, including gliomas, meningiomas, and medulloblastomas, are described in this article. The current understanding of the cell-of-origin of these neoplasms is reviewed, which suggests that the malignant phenotype is propelled by cells with stem-like qualities. A comprehensive understanding of the molecular basis of transformation and the cell-of-origin of these neoplasms will enable the formulation of more targeted treatment alternatives that could improve survival and quality of life.

What is the best adjuvant treatment for very young patients with medulloblastoma?

The standard treatment for medulloblastoma is surgery followed by adjuvant chemotherapy and external beam radiotherapy to the craniospinal axis and posterior fossa. However, in very young children, craniospinal irradiation has a more significant detrimental effect in terms of neurocognitive function and growth. This article reviews the different strategies used for very young patients with medulloblastoma.

Current treatment approaches to early childhood medulloblastoma

Treatment of medulloblastoma, the most common malignant brain tumor of childhood, is particularly challenging in very young children, owing to the increased susceptibility of the immature brain to treatment-induced neurocognitive deficits. Three promising strategies have been developed in combination with systemic postoperative chemotherapy, to avoid craniospinal irradiation for young children with nonmetastatic medulloblastoma, these include: high-dose chemotherapy, with and without local radiotherapy; intraventricular chemotherapy; and local radiotherapy. More intensified strategies may be required for metastatic medulloblastoma. Future studies will clarify the prognostic relevance of desmoplasia, postoperative residual tumor and biological markers to improve stratification criteria by risk-adapted treatment recommendations. An international Phase III trial for young children with nonmetastatic medulloblastoma, comparing survival rates and neurocognitive outcomes of different treatment strategies by standardized criteria, is under discussion.

Activity of postoperative carboplatin, etoposide, and high-dose methotrexate in pediatric CNS embryonal tumors: results of a phase II study in newly diagnosed children

BACKGROUND

Chemotherapy is used as an alternative to irradiation or to minimize the irradiation exposure among infants with medulloblastoma or other CNS embryonal tumors. Adjuvant chemotherapy is commonly used in older children with high-risk medulloblastoma to improve survival or to allow a reduction in the craniospinal irradiation dose in standard-risk patients. However, optimal multimodality therapy, including the precise role of chemotherapy, has not been defined for these groups of patients. The objective of the present study is to assess the efficacy and toxicity of four postoperative courses of carboplatin, etoposide, and high-dose methotrexate in newly diagnosed children with medulloblastoma or other CNS embryonal tumors.

PROCEDURE

Twenty-eight children, aged from 0.3 to 15.9 years (median, 6.2 years) with post-operative measurable residual CNS embryonal tumors were enrolled, comprising medulloblastoma (n = 19), supratentorial PNET (n = 7), and pineoblastoma (n = 2). Post-operative chemotherapy comprised carboplatin 350 mg/m(2) and etoposide 100 mg/m(2) on Days 1 & 2, and methotrexate 8 g/m(2) on Day 3, repeated at 21-28-day intervals for a total of four courses. Therapy following completion of the initial Phase II study was influenced by patient age and investigator preference.

RESULTS

The combined complete response rate (CR, 7/19) and partial response rate (PR, 7/19) was 74% in patients with medulloblastoma, 89% for patients with PNET/pineoblastoma (CR, 2/9 and PR, 6/9), and for all patients it was 79%. Patients aged < 3 years at diagnosis had a combined PR and CR rate of 71% compared to 81% in patients aged > 3 years. Treatment was well tolerated although myelosuppression and thrombocytopenia were common.

CONCLUSIONS

The combination of carboplatin, etoposide, and high-dose methotrexate is highly active in pediatric patients with CNS embryonal tumors.

Adult medulloblastoma: prognostic factors and patterns of relapse

OBJECTIVE

To determine the patterns of relapse and the prognostic factors for adult medulloblastomas treated in the magnetic resonance imaging era.

METHODS

Between 1986 and 1996, 32 adult patients (age, > or =16 yr) with medulloblastomas confined to the craniospinal axis were treated in our institutions. Twenty cases involved classic histological features and 12 involved the desmoplastic variant. The Chang staging distribution was as follows: T1, 2; T2, 17; T3, 10; T4, 3; M0, 24; M1, 1; M2, 4; M3, 3. Brainstem invasion was present in nine patients. Lesions were midline in 13 cases and lateral in 19. Resection was complete in 17 cases, subtotal in 6, and partial in 5, with biopsy only in 4 cases. All patients received postoperative radiotherapy, with median doses of 36 Gy to the entire craniospinal axis and 55 Gy to the posterior fossa. Twenty-four patients received chemotherapy (20 before radiotherapy, 3 after radiotherapy, and 1 before and after radiotherapy).

RESULTS

With a median follow-up period of 5.4 years, 17 patients experienced recurrences. At 5 and 8 years, overall survival rates were 83 and 45% and disease-free survival rates were 57 and 40%, respectively. The 5- and 8-year posterior fossa control rates were 67 and 59%, respectively. Twenty-nine percent of all relapses occurred more than 5 years after treatment. The posterior fossa was the most common site of relapses. In univariate analyses, factors adversely affecting posterior fossa control were less than complete resection (P<0.001), the presence of brainstem invasion (P = 0.02), and the use of chemotherapy (P = 0.03). The overall radiotherapy duration was marginally significant in predicting posterior fossa control, with 5-year posterior fossa control rates of 81 and 49% for durations of less than 48 days and 48 days or more, respectively (P = 0.06). In a multivariate analysis, complete resection was predictive of improved posterior fossa control (P = 0.02) and disease-free survival (P = 0.02) rates. Of the eight low-risk patients who received radiotherapy alone, three experienced recurrences in the bone as the only site of relapse.

CONCLUSION

Late relapse is common among adult patients with medulloblastomas, and long-term follow-up monitoring is important. Because of the high risk of systemic failure among the low-risk patients treated with radiotherapy alone, the role of chemotherapy for this group of patients needs to be further investigated. Complete resection, the absence of brainstem invasion, and an overall radiotherapy duration of less than 48 days are important prognostic factors.

Treatment of children with medulloblastomas with reduced-dose craniospinal radiation therapy and adjuvant chemotherapy: A Children's Cancer Group Study

PURPOSE

Medulloblastoma is the most common malignant brain tumor of childhood. After treatment with surgery and radiation therapy, approximately 60% of children with medulloblastoma are alive and free of progressive disease 5 years after diagnosis, but many have significant neurocognitive sequelae. This study was undertaken to determine the feasibility and efficacy of treating children with nondisseminated medulloblastoma with reduced-dose craniospinal radiotherapy plus adjuvant chemotherapy.

PATIENTS AND METHODS

Over a 3-year period, 65 children between 3 and 10 years of age with nondisseminated medulloblastoma were treated with postoperative, reduced-dose craniospinal radiation therapy (23.4 Gy) and 55.8 Gy of local radiation therapy. Adjuvant vincristine chemotherapy was administered during radiotherapy, and lomustine, vincristine, and cisplatin chemotherapy was administered during and after radiation.

RESULTS

Progression-free survival was 86% +/- 4% at 3 years and 79% +/- 7% at 5 years. Sites of relapse for the 14 patients who developed progressive disease included the local tumor site alone in two patients, local tumor site and disseminated disease in nine, and nonprimary sites in three. Brainstem involvement did not adversely affect outcome. Therapy was relatively well tolerated; however, the dose of cisplatin had to be modified in more than 50% of patients before the completion of treatment. One child died of pneumonitis and sepsis during treatment.

CONCLUSION

These overall survival rates compare favorably to those obtained in studies using full-dose radiation therapy alone or radiation therapy plus chemotherapy. The results suggest that reduced-dose craniospinal radiation therapy and adjuvant chemotherapy during and after radiation is a feasible approach for children with nondisseminated medulloblastoma.

Childhood medulloblastoma: progress and future challenges

Medulloblastoma and other primitive neuroectodermal tumors are the most common malignant tumors of childhood. Progress has been slowly made in the management of such tumors. Long-term neurocognitive sequelae of treatment in children with medulloblastoma are common and recent treatment trials have attempted to reduce the amount of craniospinal radiation therapy or delay radiation therapy in attempts to reduce such sequelae. Surgery remains a critical component of treatment, although there is increasing concern about surgically-related complications, including the cerebellar mutism syndrome. For older children, craniospinal radiation remains an integral part of management. However, recent studies have suggested an excellent outcome after reduced-dose craniospinal radiation therapy and adjuvant chemotherapy. The role of chemotherapy is expanding for children with medulloblastoma and is now presently a component of protocols for children with average-risk and poor-risk disease. For children with poor-risk disease, intensifications of chemotherapy both during and after radiation therapy are presently being explored. Treatment of infants and young children with medulloblastoma remains problematic and a variety of different approaches are being investigated with the aims of both improving outcome and reducing long-term sequelae.

Chemotherapy as prophylaxis and treatment of meningosis in children less than 3 years of age with medulloblastoma

The outcome of children less than 3 years of age with medulloblastoma has been poor in comparison to older children. The cure rates were below 30%, and the quality of life for cured children was frequently reduced by a complex syndrome of long-term sequelae including intellectual retardation and growth hormone deficiency. Due to the deleterious side-effects of radiotherapy in very young children chemotherapy has played an important role in this group of patients. Firstly, chemotherapy should improve their survival rate. Secondly, it should allow dose reduction of craniospinal irradiation and a smaller involved field. With the goal of improving quality of life radiotherapy should be delayed or even replaced by postoperative chemotherapy. The EFS of low-risk patients steadily improved and is now as high as at least 50%. Since most patients of this group do not need radiation, treatment-related long-term sequelae are minimal. High-risk patients, by contrast, with metastatic disease or measurable postoperative tumor still have a very disappointing progression-free survival in a range below 30% at 3 to 4 years in all large studies. Therefore prevention and effective therapy of meningosis, as well as a good response to induction chemotherapy, are essential for the outcome. Strategies to increase the efficacy of conventional treatment modalities in high-risk patients are under investigation. Recently, interesting results have been published on high-dose chemotherapy followed by autologous stem cell rescue and intraventricular administration of the alkylating agent mafosfamide.

Current therapy and new perspectives in the treatment of medulloblastoma

Medulloblastoma, a malignant tumor arising from the medullary velum, is the most common malignant brain tumor of childhood. Local extension into the cerebellar hemisphere, infiltration of the floor of the fourth ventricle, and seeding into the subarachnoid space are common. Early diagnosis and improved treatment consisting of surgery followed by radiation and chemotherapy for selected high-risk patients has contributed to a dramatic change in survival. This article reviews current treatment strategies and describes new therapies that have the potential to improve the outlook of children with medulloblastoma.

Neurotrophins in cerebellar granule cell development and medulloblastoma

Medulloblastomas may be derived from granule cells of the developing cerebellum. Children with tumors expressing high levels of the neurotrophin-3 receptor, TrkC, have a more favorable outcome. During development, TrkC is expressed in the most mature granule cells. Favorable medulloblastomas may be derived from more highly differentiated granule cells.

Chemotherapy for medulloblastomas and primitive neuroectodermal tumors

In the past two decades, chemotherapy has proven to be an increasingly more effective modality in the treatment of medulloblastoma. Current evidence suggests that chemotherapy be included as part of standard treatment for all patients with high-risk medulloblastoma. Ongoing multi-centre trials are determining whether chemotherapy should be added to reduced dose radiotherapy as a substitute therapy for standard-dose radiotherapy. The major randomized and non-randomized chemotherapy trials for newly diagnosed patients with medulloblastoma or for patients at recurrence are presented. It is hoped that the addition of chemotherapy will eventually lead to improved survival rates as well as the reduction in the craniospinal radiotherapy dose for patients with medulloblastoma.

Progress resulting from clinical trials. Solid tumors in childhood cancer

Solid tumors account for approximately 70% of malignant neoplasms in children younger than 15 years of age. The 5-year survival of children with solid tumors increased from 27% to 70% between 1960 and 1990. The slope of the curve that describes the change in survival over this period is remarkably constant, reflecting the nature of progress made through clinical trials. In addition to providing data important for the refinement of treatment for specific tumors, clinical trials have made numerous important, global contributions for the practice of oncology. The development of uniform response criteria, for example, was necessitated by clinical trials. The identification of histologic subtypes and the recognition of prognostic variables have permitted refinements in diagnosis and staging. By exploring novel strategies for the integration of different therapeutic modalities, clinical trials have identified indications for the use of presurgical chemotherapy, preradiation chemotherapy, and second-look and delayed primary surgeries. Refinements in the utilization of chemotherapy have been made possible by the evaluation of new agents, the study of dose intensity, and the use of the "window of opportunity" to identify active agents for tumors for which there is no effective treatment. Clinical trials have been instrumental in defining the late effects of treatment, investigating the causes of childhood cancer through epidemiologic studies, and supporting cancer biology research. The close collaboration of basic and clinical investigators offers the best opportunity for realizing the rewards of transitional research.

High dose chemotherapy with stem-cell transplantation in a metastatic medulloblastoma in an adult: a case report and review of the literature

Medulloblastoma is a rare tumor in adult. High doses of megavoltage irradiation of the posterior fossa have been resulted in a better survival (48 to 78% at 5 years) of the patient. It is sensitive to a wide variety of chemotherapy drugs, but adjuvant chemotherapy has not been proved effective in adults although data are limited. We report the case of a cerebellar medulloblastoma with bony and medullar metastases. High-dose chemotherapy with peripheral stem-cell transplantation was performed while the patient was in remission following conventional chemotherapy. Complete remission lasted for 8 months. This therapeutic approach of metastatic medulloblastoma might be of value as this tumor is chemosensitive and not cured by conventional treatment. Internal radiotherapy by Samarium-153 was also carried out and proved to be an effective palliative treatment of pain.

Pre-irradiation chemotherapy and hyperfractionated radiation therapy 66 Gy for children with brain stem tumors. A phase II study of the Pediatric Oncology Group, Protocol 8833

BACKGROUND

Fewer than 20% of children with intrinsic brain stem tumors survive longer than 2 years. Although some improvement has been noted in recent trials using higher doses of hyperfractionated radiation therapy (HRT), the feasibility of pre-irradiation chemotherapy has not been explored in these patients with poor prognosis.

METHODS

Between February 1988 and March 1989, 37 patients were entered onto a Phase II Pediatric Oncology Group study for evaluating the feasibility, response, and toxicity of treating children with high-risk brain stem tumors with chemotherapy followed by HRT (66 Gy). Chemotherapy consisted of four cycles of cisplatin (100 mg/m2) plus cyclophosphamide (3 g/m2).

RESULTS

Of 32 eligible patients, 65% improved clinically during the first 2-3 cycles of chemotherapy; 75% of those improving were weaned from steroids. On neuroradiology review of scans before and after chemotherapy, 3 patients had partial responses (PR, > 50% shrinkage), 23 had stable disease (SD), and 6 had progressive disease (PD). The median survival was 9 months. The three patients who attained a PR on chemotherapy were among the longest survivors at 38 plus, 44 plus, and 40 months. Toxicities included profound but brief marrow suppression, transient electrolyte-renal dysfunction, and ototoxicity. Brain stem swelling from intravenous fluids caused transient deterioration in two patients. Six patients developed an unusual syndrome of transient marrow suppression after HRT.

CONCLUSIONS

This study suggests that pre-irradiation chemotherapy can be successfully added to the treatment of patients with brain stem tumors with both clinical and objective responses noted, but that other agents must be identified to overcome the apparent development of drug resistance and to improve survival.

Hypersensitivity reactions to procarbazine with mechlorethamine, vincristine, and procarbazine chemotherapy in the treatment of glioma

The authors report the clinical features of hypersensitivity reactions believed to result from procarbazine in eight patients treated with mechlorethamine, vincristine, and procarbazine (MOP) for high-grade glioma. There was one instance of hypersensitivity in 7 patients treated for recurrent disease and seven instances in 16 patients treated with an adjuvant protocol using MOP directly after surgery. Maculopapular rash was seen in seven of eight, fever was seen in four of eight, and reversible abnormal liver function test results were seen in three of four patients. Pulmonary toxic effects were seen in five of eight patients and consisted of isolated interstitial pneumonitis in one, fever and infiltrate after rechallenge with procarbazine after previous rash in two, and cough accompanying rash in two. The toxic effects were mild to moderate in six patients but severe to life threatening in the two who were rechallenged after development of rash. The observed incidence of rash during adjuvant therapy was higher than that previously found by the authors for recurrent disease, and it appears to be higher than has been reported in Hodgkin's disease, lymphoma, and other solid tumors. The findings by the authors suggest that a high index of suspicion be kept for hypersensitivity reactions to procarbazine when treating primary brain tumors and that, contrary to the experience in other settings, procarbazine be stopped if rash develops.

Choroid plexus tumors in childhood. Response to chemotherapy, and immunophenotypic profile using a panel of monoclonal antibodies

Clinical and immunophenotypic (IP) data are presented on three children with choroid plexus (CP) tumors. Two children ages 0.2 and 2 years old with histologically proven malignant tumors had subtotal tumor resections and were treated with ten monthly cycles of eight-drugs-in-1-day chemotherapy without radiation therapy (XRT). Both are free of tumor 4 and 7 years later. The literature on survival of children with CP carcinomas after chemotherapy and XRT is reviewed. Monoclonal antibodies to 17 neuroectodermal, neuronal, glial, and leukocytic markers on frozen sections were used to IP the two malignant tumors and a CP papilloma. All tumors expressed two neuroectodermal markers (PI-153/3 and UJ 223.8), cytokeratin 19, and a neural and leukocyte marker (Thy-1). Two of three expressed neurofilament protein (NF-H) and glial fibrillary acidic protein (GFAP) and one expressed NF-M and common leukocyte antigen. None had strong expression for the panneuroectodermal antigen UJ13/A. There was variable expression of the other markers. The most common IP profile for CP tumors (cytokeratin 18+, PI-153/3+, Thy-1+, UJ 223.8+, and GFAP+ and UJ13A-, UJ 127.11-, and NF-L-) is discussed in the context of the current knowledge of the ontogenetic origin of the CP. It was concluded that chemotherapy for malignant CP tumors can be associated with long-term survival in young children and that the unique IP profile of CP tumors with coexpression of three intermediate filaments suggests new and provocative evidence of their cellular complexity and heterogeneity.

The clinical pharmacology and use of antimicrotubule agents in cancer chemotherapeutics

Although there has been a rapid expansion of the number of classes of compounds with antineoplastic activity, few have played a more vital role in the curative and palliative treatment of cancers than the antimicrotubule agents. Although the vinca alkaloids have been the only subclass of antimicrotubule agents that have had broad experimental and clinical applications in oncologic therapeutics over the last several decades, the taxanes, led by the prototypic agent taxol, are emerging as another very active class of antimicrotubule agents. After briefly reviewing the mechanisms of antineoplastic action and resistance, this article comprehensively reviews the clinical pharmacology, therapeutic applications, and clinical toxicities of selected antimicrotubule agents.

The change in patterns of relapse in medulloblastoma

The authors reviewed 89 patients treated for cerebellar medulloblastoma between 1970 and 1989 to determine the impact of changing treatment (high-dose posterior fossa radiation therapy and chemotherapy) on the pattern of failure in medulloblastoma. Between 1970 and 1983, 50 patients (median follow-up, 110 months) were treated with surgery and postoperative craniospinal irradiation (CSI). Nineteen of the 50 (38%) recurred in the central nervous system (CNS). Isolated systemic (bone) metastases occurred in six. The median time to the development of bone metastases was 12 months. Since 1984, 39 patients (median follow-up, 27 months) were treated with preradiation chemotherapy consisting of cisplatin and vincristine for 9 weeks before initiation of CSI. Nine of the 39 (23%) patients recurred in the CNS. There were no systemic failures in this cohort. The actuarial 5-year disease-free survival was 55 +/- 7% for the earlier cohort and 72 +/- 8% for the later cohort (P equals 0.3). Posterior fossa recurrence was associated with radiation therapy to this area. The cumulative incidence of posterior fossa relapse was 50 +/- 13% in patients who received less than 5300 cGy and 18 +/- 7% in those who received 5300 cGy or more (P equals 0.005). All six bone relapses were in patients treated with CSI alone and 5300 cGy or more to the posterior fossa for a 5-year cumulative incidence of bone metastases of 18 +/- 7% compared with 0% for patients treated with 5300 cGy or more and chemotherapy (P equals 0.03). The authors concluded that high-dose radiation therapy has altered the pattern of relapse with an increase in systemic recurrence after radiation therapy alone that is now equivalent to the risk of recurrence in the posterior fossa. Chemotherapy may be indicated in an attempt to decrease this high risk of systemic metastases.

Nitrogen mustard, vincristine, procarbazine, and prednisone as adjuvant chemotherapy in the treatment of medulloblastoma. A Pediatric Oncology Group study

In a randomized postoperative trial, adjuvant post-irradiation chemotherapy, consisting of nitrogen mustard, vincristine, procarbazine, and prednisone (MOPP), was tested versus radiation therapy alone for newly diagnosed medulloblastoma in patients between 1 and 21 years of age. Patients treated with irradiation plus MOPP had a statistically significant increase in overall survival rate at 5 years posttreatment compared to patients treated with radiation therapy alone (74% vs. 56%; p = 0.06, adjusted for race and gender). Although the overall study failed to show a statistically significant advantage for irradiation plus MOPP in event-free survival (p = 0.18), statistical significance was attained in children 5 years of age or older (p = 0.05). More severe hematological toxicities occurred in the group with irradiation plus MOPP; however, this hematotoxicity appeared to be tolerable and acceptable. These results suggest that patients may benefit from combined irradiation and chemotherapy following surgery for medulloblastoma.

Chemotherapy for medulloblastoma/primitive neuroectodermal tumors of the posterior fossa

Chemotherapy has only marginal efficacy in adult malignant brain tumors. In contrast, drug therapy is considerably more effective in medulloblastoma/primitive neuroectodermal tumors (MB/PNET) of the posterior fossa, the most common childhood primary central nervous system tumor. At the time of disease recurrence, a variety of different single agents and drug combinations result in tumor shrinkage and increased survival. The addition of chemotherapy to standard radiotherapy improves the rate and length of disease-free survival for those children with MB/PNET who have the most extensive tumors at diagnosis. It remains to be determined which drug or drug combinations are the most effective in MB/PNET, and which patients are most likely to benefit from chemotherapy. Chemotherapy may be useful to reduce or, in selected cases, obviate the need for radiotherapy and reduce treatment-related sequelae.