Postoperative neoadjuvant chemotherapy before radiotherapy as compared to immediate radiotherapy followed by maintenance chemotherapy in the treatment of medulloblastoma in childhood: results of the German prospective randomized trial HIT '91

M1 Medulloblastoma: high risk at any age

BACKGROUND

The prognosis for children with M1 medulloblastoma (positive CSF cytology) has not been well-defined.

METHODS

We retrospectively reviewed the records of 285 newly diagnosed medulloblastoma patients treated between 1984 and 2006. Older children received post-operative craniospinal and tumor bed irradiation; radiotherapy for younger children depended on treatment era and physician/family preference.

RESULTS

55 patients were <3 years old and 230 patients were >or= 3 years old at diagnosis. We detected significant (P < 0.0001) associations between M1 disease and EFS for the entire cohort and for both younger and older patients. Among younger children, M1 patients had lower EFS than M0 (P = 0.0044).

CONCLUSIONS

Children <3 years old with M1 medulloblastoma fared poorly in our small series. Survival for older children with M1 disease treated with higher-dose CSI was better than that of M2/M3 patients, but still less than optimal; our findings do not support reduction in therapy for either cohort.

Medulloblastoma: what is the role of molecular genetics?

Among pediatric malignancies, medulloblastoma (MB) is one of the most common malignant tumors of the CNS. In the past few years, thanks to a multidisciplinary approach including surgery, chemo- and radiation therapy, survival has significantly improved. Despite that, a third of patients still have a low chance of being cured and long-term survivors experience severe treatment-related sequelae. MBs are usually classified according to a clinical risk stratification, based on histological features, age at diagnosis, extent of tumor resection and presence or absence of metastases. However, these clinical variables have recently been reported to be poor for defining risk-related disease. Retrospective studies have identified histological or biological factors that have distinct roles in prognosis. As several pathways have been discovered to be involved in MB pathogenesis, they should be taken into account to more accurately stratify patients and their treatment and to develop innovative therapies.

Neuropsychological outcome following intensity-modulated radiation therapy for pediatric medulloblastoma

BACKGROUND

Combined cisplatin chemotherapy and cranial irradiation for treatment of medulloblastoma in children can cause significant ototoxicity and impair cognitive function and quality of life. We have previously demonstrated the conformal technique of intensity-modulated radiation therapy (IMRT) to reduce ototoxicity, however, it has been suggested that IMRT may increase risk of cognitive deficits compared to conventional radiation therapy (CRT). This study compared the impact of the two treatments on measures of neurocognitive functioning.

PROCEDURE

Twenty-five pediatric patients with medulloblastoma were treated either with CRT or IMRT. In addition they received neurocognitive assessments to evaluate long-term functional outcome. Statistical analyses between the two groups were conducted to compare levels and profiles of performance on tests not confounded with hearing loss.

RESULTS

When compared to CRT, children treated with IMRT did not perform more poorly on any of the measures. Both groups' mean performance was significantly lower than published norms on several of the measures employed.

CONCLUSION

The benefit of reduced ototoxicity with IMRT does not appear to be at the cost of a decline in nonverbal intellectual abilities, visual-spatial skills, processing speed, or fine motor dexterity when compared to CRT in children with medulloblastoma.

Intrathecal chemotherapy delivered by a lumbar-thecal catheter in metastatic medulloblastoma: a case illustration

BACKGROUND

Medulloblastoma is the most common malignant brain tumour in children. Despite recent advances, the prognosis in high risk patients remains poor. Further improvement in survival is dependent upon the development of strategies to attack the tumour more effectively, but with less toxicity. Intrathecal chemotherapy, is an ideal but currently underused method of directly targeting residual tumour within the area of resection and the leptomeningeal disease commonly associated with this tumour.

METHOD

We describe the case of a 12 yr old child with metastatic medulloblastoma, who received intrathecal topotecan via a spinal catheter.

CONCLUSION

This method represents a simple, safe and effective method of delivering an even and widespread distribution of drug within the cerebrospinal fluid (CSF) of the neuroaxis. With new agents being identified and others in the early stages of development, intrathecal chemotherapy may emerge as an important therapeutic option to consider when faced with such challenging cases.

Medulloblastoma: from molecular pathology to therapy

Medulloblastoma is the most common malignant tumor of central nervous system in children. Patients affected by medulloblastoma may be categorized as high-risk and standard-risk patients, based on the clinical criteria and histologic features of the disease. Currently, multimodality treatment, including surgery, radiotherapy, and chemotherapy is considered as the most effective strategy against these malignant cerebellar tumors of the childhood. Despite the potential poor outcomes of these lesions, the 5-year survival stands, at present, at 70% to 80% for standard-risk patients, whereas high-risk patients have a 5-year survival of 55% to 76%. Attempts to further reduce the morbidity and mortality associated with medulloblastoma have been restricted by the toxicity of conventional treatments and the infiltrative nature of the disease. Over the past decade, new discoveries in molecular biology have revealed new insights in signaling pathways regulating medulloblastoma tumor formation. Recent advances in the molecular biology of medulloblastoma indicate that the classification of these embryonal tumors, solely based on histology and clinical criteria, may not be adequate enough. Better understanding of the growth control mechanisms involved in the development and progression of medulloblastoma will allow a better classification, leading to the improvement of the existing therapies, as well as to the development of new therapeutic approaches.

Medulloblastoma in childhood: new biological advances

Medulloblastoma is the most common embryonal tumour in children. Patients with medulloblastoma are currently staged as average-risk or poor-risk on the basis of clinical findings. With current multimodality therapy, nearly 90% of children with average-risk, non-disseminated medulloblastoma have 5-year event-free survival, and those with high-risk disease have a 60-65% survival rate; however, the outcome for younger children, particularly infants, is worse. Children who survive medulloblastoma are at risk of long-term sequelae related to the neurological effects of the tumour, surgery, or radiotherapy, and the additive effects of chemotherapy. Molecular biology has changed our understanding of medulloblastoma and has implications for diagnostic stratification and treatment. As newer biological agents are translated from the lab to the bedside, clinicians need to understand the fundamental signalling pathways that are targeted during therapy. Greater understanding of the molecular biology of medulloblastoma is needed so that more children can be cured or have an improved quality of life.

Paediatric medulloblastoma: patterns of care and radiotherapy quality assurance in Australia

The purpose of this study was to document how children in Australia with medulloblastoma are being treated and to evaluate the quality of radiotherapy (RT) delivered. The Radiotherapy Database of the Australian and New Zealand Children's Haematology and Oncology Group was used to identify 46 children with medulloblastoma younger than the age of 15 years treated with radical intent by craniospinal irradiation between 1997 and 1999 inclusively. Twenty-six patients had completely resected disease without evidence of disease spread. Of these, 16 patients received a craniospinal RT dose of <25 Gy in addition to chemotherapy. RT treatment immobilization methods varied, as did planning methods. RT dose to critical structures was recorded on treatment plans for only 15% of patients. The average systematic error in shield placement at the posterior orbit was 5.2 mm, and two-thirds of patients were 'overshielded' at this site. Adequate coverage of the distal end of the thecal sac was achieved in fewer than 50% of on-treatment verification films for 21 of 45 patients. With a reduction in RT dose to the craniospinal axis for paediatric medulloblastoma, greater attention is needed for patient immobilization, documentation of RT dose to critical structures and the placement and reproducibility of shielding.

Long-term results of a prospective study on the treatment of medulloblastoma in adults

BACKGROUND

Because medulloblastoma (MB) is rare in adults, the few studies on this condition have been retrospective, and the follow-up has tended to be short. Furthermore, the different therapeutic strategies used in these patients has made it difficult to assess survival rates and prognostic factors.

METHODS

In 1989, a prospective Phase II trial was initiated to evaluate the efficacy of treatment for adults with MB. Patients were staged completely with a neuroradiologic examination of the brain and neuroaxis and by cerebrospinal fluid cytology, according to Chang's staging system. Low-risk patients received radiotherapy alone, whereas high-risk patients received 2 cycles of upfront chemotherapy followed by radiotherapy and adjuvant chemotherapy. The current article reports on the long-term results from that trial.

RESULTS

After a median follow up of 7.6 years, among a total of 36 adults with MB, the overall progression-free survival (PFS) and overall survival (OS) rates at 5 years were 72% and 75%, respectively. In low-risk patients, the 5-year PFS rate was 80%, and the 5-year OS rate was 80%; in high-risk patients, the 5-year PFS rate was 69%, and the 5-year OS rate was 73%.

CONCLUSIONS

In adult patients with MB, long-term follow-up was essential for evaluating the real impact of treatments. Low-risk and high-risk patients did not differ significantly in terms of PFS or OS.

Temozolomide treatment of an adult with a relapsing medulloblastoma

Temozolomide is an oral cytotoxic agent that has demonstrated its interest in high grade glioma tumors. This drug can be used either concomitantly with radiotherapy or as chemotherapy. The prognosis of relapsing medulloblastoma is poor and treatment is often difficult, especially after radiotherapy. Here, we report the use of temozolomide in an adult presenting relapsing medulloblastoma. An initial partial response was observed for this previously heavily treated patient. This observation suggests this drug may be useful in medulloblastoma, either as conventional chemotherapy or for use together with radiotherapy.

Prognostic relevance of clinical and biological risk factors in childhood medulloblastoma: results of patients treated in the prospective multicenter trial HIT'91

PURPOSE

To identify better risk stratification systems in childhood medulloblastoma based on clinical factors and analysis of routinely processed formalin-fixed tumor material.

EXPERIMENTAL DESIGN

Formalin-fixed paraffin-embedded tumor samples from well-documented patients treated within the prospective randomized multicenter trial HIT'91 were analyzed for DNA amplification of c-myc and N-myc (n=133) and mRNA expression of c-myc and trkC (n=104; compared with human cerebellum) using validated methods of quantitative PCR and reverse transcription-PCR. Results were related to clinical data and outcome.

RESULTS

TrkC and c-myc mRNA expression were identified as independent prognostic factors by multivariate analysis. Three risk groups were identified. (a) Favorable risk group: all 8 patients (2 metastatic) with high trkC (>1x human cerebellum) and low c-myc mRNA expression (<or=1x human cerebellum) remained relapse-free [7-year event-free survival (EFS), 100%]. (b) Poor risk group: 10 of 15 patients with metastatic disease and high c-myc and low trkC mRNA expression relapsed (7-year EFS, 33%). (c) Intermediate risk group: the 7-year EFS of the remaining 78 patients was 65%. Among 47 M(0) stage patients, all 10 patients with high trkC mRNA expression remained relapse-free compared with 15 events in 37 patients with low trkC mRNA expression levels (7-year EFS, 100% versus 62%; P=0.056).

CONCLUSIONS

Whereas the collection of fresh-frozen tumor samples remains a major challenge in large clinical trials, routinely processed paraffin-embedded tissue samples can be used to quantitate the prognostic biological markers trkC and c-myc. On prospective validation of cutoff levels, this may lead to improved stratification of treatment for children with medulloblastoma.

Emerging treatments and gene expression profiling in high-risk medulloblastoma

The past decades have seen an increase in the survival rates of patients with standard-risk medulloblastoma. Efforts have, therefore, been focused on obtaining better results in the treatment of patients with high-risk tumors. In addition to consolidated therapies, novel approaches such as small molecules, monoclonal antibodies, and antiangiogenic therapies that aim to improve outcomes and quality of life are now available through new breakthroughs in the molecular biology of medulloblastoma. The advent of innovative anticancer drugs tested in brain tumors has important consequences for personalized therapy. Gene expression profiling of medulloblastoma can be used to identify the genes and signaling transduction pathways that are crucial for the tumorigenesis process, thereby revealing both new targets for therapy and sensitive/resistance phenotypes. The interpretation of microarray data for new treatments of patients with high-risk medulloblastoma, as well as other poor prognosis tumors, should be developed through a consensus multidisciplinary approach involving oncologists, neurosurgeons, radiotherapists, biotechnologists, bioinformaticists, and other professionals.

Common Strategy for Adult and Pediatric Medulloblastoma: A Multicenter Series of 253 Adults

PURPOSE

To assess prognostic factors for adults with medulloblastoma in a multicenter, retrospective study.

METHODS AND MATERIALS

Data were collected by file review or mail inquiry for 253 adults treated between 1975 to 2004. Radiologists or surgeons assessed disease characteristics, such as volume and extension. Patients were classified as having either high- or standard-risk disease. Prognostic factors were analyzed.

RESULTS

Median patient age was 29 years. Median follow-up was 7 years. Radiotherapy was delivered in 246 patients and radiochemotherapy in 142. Seventy-four patients relapsed. Respective 5- and 10-year overall survival rates were 72% and 55%. Univariate analysis showed that survival significantly correlated with metastasis, postsurgical performance status, brainstem involvement, involvement of the floor of the fourth ventricle (V4), and radiation dose to the spine and to the posterior cerebral fossa (PCF). By multivariate analysis, brainstem, V4 involvement, and dose to the PCF were negative prognostic factors. In the standard-risk subgroup there was no overall survival difference between patients treated with axial doses of >or=34 Gy and patients treated with craniospinal doses <34 Gy plus chemotherapy.

CONCLUSION

We report the largest series of medulloblastoma in adults. Prognostic factors were similar to those observed in children. Results suggest that patients with standard-risk disease could be treated with radiochemotherapy, reducing doses to the craniospinal area, maintaining at least 50 Gy to the PCF. The role of chemotherapy for this group is still unclear. A randomized study should be performed to confirm these results, but because frequency is very low, such a study would be difficult.

Feasibility and toxicity of intrathecal liposomal cytarabine in 5 children and young adults with refractory neoplastic meningitis

Intrathecal (IT) treatment of neoplastic meningitis secondary to relapsed or refractory malignancies is a major challenge for clinicians. We studied feasibility and toxicity of IT administered liposomal cytarabine on a compassionate basis in 5 patients (male, n=4; female, n=1; age at diagnosis 5 to 18 y) with recurrent acute lymphoblastic leukemia (n=3), primary refractory acute myeloid leukemia (n=1), or relapsed medulloblastoma (n=1). All of them had evidence of meningeal involvement as shown by presence of leukemic blasts or solid tumor cells on cytologic examination of cerebrospinal fluid and were refractory to standard central nervous system (CNS) therapy. A total of 33 doses were given. Leukemic blasts or solid tumor cells were cleared from cerebrospinal fluid in all patients. IT liposomal cytarabine was well tolerated in 2 patients, but may have contributed to neurologic side effects in 2 other patients with 1 patient who received high-dose methotrexate 96 hours before IT liposomal cytarabine developing transient encephalopathy. Another patient experienced seizures after 6 well-tolerated doses of IT liposomal cytarabine. In the fifth patient, treatment with IT liposomal cytarabine was not continued after a single dose because of toxic cauda equina syndrome, resulting from previous intensive CNS therapy. If administered simultaneously to other neurotoxic drugs, IT liposomal cytarabine may contribute to neurologic side effects in patients who had received prior intensive CNS-directed therapy. IT liposomal cytarabine should, therefore, be used cautiously, if a patient receives other potentially neurotoxic drugs simultaneously.

Pilot study of ifosfamide/carboplatin/etoposide (ICE) for peripheral blood stem cell mobilization in patients with high-risk or relapsed medulloblastoma

OBJECTIVES

The purpose of this study is to evaluate the stem cell mobilization capacity, anti-tumor effect, and feasibility of ifosfamide/carboplatin/etoposide (ICE) for transplant-eligible patients with medulloblastoma.

MATERIALS AND METHODS

Six patients (23 months to 18 years old) with high-risk or relapsed medulloblastoma received one cycle of ICE, which consisted of ifosfamide at 1.8 g/m(2) for 5 days, carboplatin 400 mg/m(2) for 2 days, and etoposide 100 mg/m(2) for 5 days. Stem cells were mobilized with ICE followed by granulocyte colony-stimulating factor at 10 microg kg(-1) day(-1).

RESULTS

After one cycle of ICE, the median number of harvested CD34+ cells per apheresis session was 11.85 x 10(6) cells/kg (range, 0.2 to 71.2 x 10(6) cells/kg). Two patients obtained a complete response and three patients a partial response. All patients experienced severe myelosuppression, and three infectious toxicities were observed.

CONCLUSIONS

These results suggest that ICE is optimal for mobilizing stem cells, effective for high-risk or relapsed medulloblastoma, and tolerable with limited non-hematological toxicity.

Radiation-induced brain tumours in nevoid basal cell carcinoma syndrome: implications for treatment and surveillance

INTRODUCTION

We report two cases of radiation-induced intracranial tumours after treatment for medulloblastoma presenting in children with nevoid basal cell carcinoma syndrome.

DISCUSSION

These cases illustrate the need for judicious use of post-operative radiotherapy as secondary tumors are commonly reported. This is particularly important as the initial tumour in this cohort is of the 'less aggressive' desmoplastic subtype.

Supratentorial primitive neuroectodermal tumors of the central nervous system frequently harbor deletions of theCDKN2A locus and other genomic aberrations distinct from medulloblastomas

Supratentorial primitive neuroectodermal tumors (stPNETs) and medulloblastomas have long been thought to arise from a common cell type in the subventricular germinal matrix. Because of the infrequent occurrence of stPNETs, little is known about their genetic background. Here, we performed a genome-wide screening for DNA copy-number aberrations in 10 supratentorial PNETs using array-based comparative genomic hybridization (array-CGH). Comparing our findings with data from a previous array-CGH study on 47 medulloblastomas, we identified differences in the frequency of copy-number losses at chromosome regions 1p12-22.1 and 9p, and gains at 19p, all of them more frequently occurring in stPNETs. In contrast to previous reports, we detected chromosome 17 aberrations by array-CGH in 2/10 stPNETs. To validate our findings obtained by array-CGH, we analyzed the loci of interest by fluorescence in situ hybridization in an independent set of 11 stPNETs and found deletions of 9p21 in 5/11 tumors of the second set, three of them being homozygous. All 9p21 deletions were associated with loss of CDKN2A protein expression. Altogether, CDKN2A deletions were detected in 7/21 stPNETs including four homozygous deletions, whereas such deletions were only found in 4/112 medulloblastomas, all of these being heterozygous (P < 0.001). Gains of 19p (14% vs. 0% in medulloblastomas, P = 0.02) were found to be significantly more frequent in stPNETs, whereas gains of 17q (14% vs. 45% in medulloblastomas, P = 0.02) were confirmed to be more frequent in medulloblastomas. These data further support the hypothesis of two different tumor entities of embryonal neuroepithelial tumors with characteristic genetic aberrations. (c) 2007 Wiley-Liss, Inc.

Risk-adapted craniospinal radiotherapy followed by high-dose chemotherapy and stem-cell rescue in children with newly diagnosed medulloblastoma (St Jude Medulloblastoma-96): long-term results from a prospective, multicentre trial

BACKGROUND

Current treatment for medulloblastoma, which includes postoperative radiotherapy and 1 year of chemotherapy, does not cure many children with high-risk disease. We aimed to investigate the effectiveness of risk-adapted radiotherapy followed by a shortened period of dose-intense chemotherapy in children with medulloblastoma.

METHODS

After resection, patients were classified as having average-risk medulloblastoma (< or = 1.5 cm2 residual tumour and no metastatic disease) or high-risk medulloblastoma (> 1.5 cm2 residual disease or metastatic disease localised to neuraxis) medulloblastoma. All patients received risk-adapted craniospinal radiotherapy (23.4 Gy for average-risk disease and 36.0-39.6 Gy for high-risk disease) followed by four cycles of cyclophosphamide-based, dose-intensive chemotherapy. Patients were assessed regularly for disease status and treatment side-effects. The primary endpoint was 5-year event-free survival; we also measured overall survival. This study is registered with ClinicalTrials.gov, number NCT00003211.

FINDINGS

Of 134 children with medulloblastoma who underwent treatment (86 average-risk, 48 high-risk), 119 (89%) completed the planned protocol. No treatment-related deaths occurred. 5-year overall survival was 85% (95% CI 75-94) in patients in the average-risk group and 70% (54-84) in those in the high-risk group (p=0.04); 5-year event-free survival was 83% (73-93) and 70% (55-85), respectively (p=0.046). For the 116 patients whose histology was reviewed centrally, histological subtype correlated with 5-year event-free survival (p=0.04): 84% (74-95) for classic histology, 77% (49-100) for desmoplastic tumours, and 57% (33-80) for large-cell anaplastic tumours.

INTERPRETATION

Risk-adapted radiotherapy followed by a shortened schedule of dose-intensive chemotherapy can be used to improve the outcome of patients with high-risk medulloblastoma.

Treatment of high risk medulloblastomas in children above the age of 3 years: A SFOP study

AIM

Improvement of EFS of children older than 3 years with high risk medulloblastoma.

METHODS

Between 1993 and 1999, 115 patients (3-18 years, mean 8 years) with high risk medulloblastoma were included. After surgery treatment consisted of chemotherapy ('8in1' and etoposide/carboplatin) before and after craniospinal radiotherapy.

RESULTS

Patients were staged using Chang-criteria (PF residue only, M1 and M2/M3) by local investigator as well as by central review panel (82.4% concordance). Chemotherapy was well tolerated without major delays in radiotherapy. With a mean follow up of 81 months (9-119), 5-year EFS was 49.8% and OS 60.1%. In detail according to subgroups EFS was 68.8% for PF residue only, 58.8% for M1 disease and 43.1% for M2/M3.

CONCLUSION

M1 patients are legitimate high risk patients. Survival rates are still very low for high risk medulloblastoma patients and future trials should therefore focus on more intensive (chemotherapy/radiotherapy) treatment.

Role of spinal MRI in the follow-up of children treated for medulloblastoma

BACKGROUND

The purpose of the current study was to describe the usefulness of spinal magnetic resonance imaging (MRI) in children with medulloblastoma or primitive neuroectodermal tumor (PNET) of the posterior fossa.

METHODS

Children consecutively diagnosed with medulloblastoma/PNET and followed in the Hospital for Sick Children/Toronto were identified. A homogenous cohort of children treated with craniospinal irradiation as part of their initial treatment was considered. Contrast-enhanced spinal MRIs done concomitantly with cranial MRIs (doublets) were reviewed. Recurrence was defined as any new abnormal lesion (in the brain or in the spine) in symptomatic or asymptomatic patients. Doublets after the first recurrence were excluded in the final analysis. The utility of a spinal MRI in the presence of a negative cranial MRI was assessed.

RESULTS

In all, 73 patients (21 females and 52 males; median age, 6.6 years, median follow-up time, 4.3 years) had at least 1 evaluable doublet during the follow-up period. Since concomitant cranial and spinal MRI was introduced as the standard evaluation for medulloblastoma/PNET in 1991, 286 doublets were evaluable. Fourteen spinal MRIs and 25 cranial MRIs showed new nodular or leptomeningeal lesions. In 2 patients, repeat MRIs ruled out recurrence (false-positive). All confirmed spinal recurrences were associated with intracranial recurrence. Of 261 doublets with negative cranial MRI, no new lesion was identified on spinal MRI.

CONCLUSIONS

An absence of progression on cranial MRI is highly predictive of absence of progression on spinal MRI. There is little evidence that surveillance spinal MRI (in children who underwent craniospinal radiation as part of their initial treatment) improves the detection of recurrences in children with medulloblastoma.

Phase III study of craniospinal radiation therapy followed by adjuvant chemotherapy for newly diagnosed average-risk medulloblastoma

PURPOSE

To determine the event-free survival (EFS) and overall survival of children with average-risk medulloblastoma and treated with reduced-dose craniospinal radiotherapy (CSRT) and one of two postradiotherapy chemotherapies.

METHODS

Four hundred twenty-one patients between 3 years and 21 years of age with nondisseminated medulloblastoma (MB) were prospectively randomly assigned to treatment with 23.4 Gy of CSRT, 55.8 Gy of posterior fossa RT, plus one of two adjuvant chemotherapy regimens: lomustine (CCNU), cisplatin, and vincristine; or cyclophosphamide, cisplatin, and vincristine. Results Forty-two of 421 patients enrolled were excluded from analysis. Sixty-six of the remaining 379 patients had incompletely assessable postoperative studies. Five-year EFS and survival for the cohort of 379 patients was 81% +/- 2.1% and 86% +/- 9%, respectively (median follow-up over 5 years). EFS was unaffected by sex, race, age, treatment regimen, brainstem involvement, or excessive anaplasia. EFS was detrimentally affected by neuroradiographic unassessability. Patients with areas of frank dissemination had a 5-year EFS of 36% +/- 15%. Sixty-seven percent of progressions had some component of dissemination. There were seven second malignancies. Infections occurred more frequently on the cyclophosphamide arm and electrolyte abnormalities were more common on the CCNU regimen.

CONCLUSION

This study discloses an encouraging EFS rate for children with nondisseminated MB treated with reduced-dose craniospinal radiation and chemotherapy. Additional, careful, step-wise reductions in CSRT in adequately staged patients may be possible.

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.

Childhood pineoblastoma: experiences from the prospective multicenter trials HIT-SKK87, HIT-SKK92 and HIT91

OBJECTIVE

To analyze the outcome of children with pineoblastoma (PB), treated within the prospective multicenter trials HIT-SKK87, HIT-SKK92 and HIT91 of German-speaking countries.

PATIENTS

We report on 11 children suffering from PB. Five children younger than 3 years of age received chemotherapy after surgery until eligible for radiotherapy (HIT-SKK87 and HIT-SKK92). Five of six children older than 3 years were treated after surgery with immediate chemotherapy and craniospinal irradiation, and one child received maintenance chemotherapy after postoperative radiotherapy (HIT91).

RESULTS

Five of the six older children are still alive in continuous complete remission (CCR) with a median overall survival (OS) and progression free survival (PFS) of 7.9 years. Five of these six HIT91 patients responded to postoperative chemotherapy and radiotherapy. The only patient with tumor progression during initial chemotherapy achieved complete remission with radiotherapy and is alive. In contrast, all five young children died of tumor progression after a median OS of 0.9 years (PFS 0.6 years). They had either metastatic disease (M1) and/or postoperative residual tumor. Response to postoperative chemotherapy was lower than in the older age group, and only one of these children received radiotherapy.

CONCLUSIONS

Combined chemotherapy and radiotherapy were feasible and effective in the older age group, leading to prolonged remissions in five of six children. Tumor biology may be more aggressive in younger children with PB, who presented more frequently with high-risk features at diagnosis and had poorer response rates to neoadjuvant postoperative chemotherapy. More intensified treatment regimens may be needed for young children with PB.

Current therapy for medulloblastoma

In the past three decades, the survival for patients with medulloblastoma has improved remarkably. Contemporary "standard" therapy for children with medulloblastoma consists of maximal surgical resection followed by craniospinal irradiation with a boost to the posterior fossa, combined with adjuvant chemotherapy. The use of such multimodal therapeutic approaches results in progression-free survival (PFS) rates of 75% to 80% for patients with average-risk disease and approximately 60% for high-risk patients. However, despite the marked improvements in survival, many therapeutic challenges remain. Children with macroscopic metastatic disease (M2/M3) at presentation continue to fare poorly, with the best reports only attaining PFS rates up to 40%. Furthermore, despite intensive multimodal therapy, some patients have disease progression or recurrence, which for most remains incurable. The early recognition of these patients is imperative in order to institute treatment modifications, such as intensification and/or the use of novel experimental therapies. Additionally, the price for cure is clearly evident in survivors, who suffer from significant, often debilitating long-term neurocognitive and neuroendocrine sequela. Using the current clinical stratification system, a significant number of patients are overtreated and unnecessarily subjected to these long-term toxicities. This group of patients would benefit from reductions in therapy. Refinements in patient stratification and further improvement in outcome are unlikely to be achieved without improved knowledge of tumor biology. Several molecular alterations have already been identified, many of which appear to have prognostic significance. Furthermore, the disruption of molecular alterations in signaling pathways involved in the development and maintenance of medulloblastoma using novel molecularly targeted therapies promises to improve outcomes and reduce toxicity for patients with medulloblastoma. It is envisaged that in the near future children diagnosed with medulloblastoma will be more accurately stratified based on a combination of clinical variables and molecular profiles. Improved risk stratification will permit delivery of individualized therapy using conventional treatment modalities in conjunction with novel targeted therapeutic approaches.

Radiotherapy in pediatric medulloblastoma: Quality assessment of Pediatric Oncology Group Trial 9031

PURPOSE

To evaluate the potential influence of radiotherapy quality on survival in high-risk pediatric medulloblastoma patients.

METHODS AND MATERIALS

Trial 9031 of the Pediatric Oncology Group (POG) aimed to study the relative benefit of cisplatin and etoposide randomization of high-risk patients with medulloblastoma to preradiotherapy vs. postradiotherapy treatment. Two-hundred and ten patients were treated according to protocol guidelines and were eligible for the present analysis. Treatment volume (whole brain, spine, posterior fossa, and primary tumor bed) and dose prescription deviations were assessed for each patient. An analysis of first site of failure was undertaken. Event-free and overall survival rates were calculated. A log-rank test was used to determine the significance of potential survival differences between patients with and without major deviations in the radiotherapy procedure.

RESULTS

Of 160 patients who were fully evaluable for all treatment quality parameters, 91 (57%) had 1 or more major deviations in their treatment schedule. Major deviations by treatment site were brain (26%), spinal (7%), posterior fossa (40%), and primary tumor bed (17%). Major treatment volume or total dose deviations did not significantly influence overall and event-free survival.

CONCLUSIONS

Despite major treatment deviations in more than half of fully evaluable patients, underdosage or treatment volume misses were not associated with a worse event-free or overall survival.

Role of Radiotherapy in Supratentorial Primitive Neuroectodermal Tumor in Young Children: Results of the German HIT-SKK87 and HIT-SKK92 Trials

Purpose

To assess the outcome of young children with supratentorial primitive neuroectodermal tumor (stPNET) treated by intensive postoperative chemotherapy alone compared with treatment with chemotherapy and delayed radiotherapy (RT).

Patients and Methods

From 1987 to 1992, children younger than 3 years of age with stPNET were enrolled in the HIT-SKK87 trial in Germany and Austria. After surgery, low-risk patients received maintenance chemotherapy before RT. In high-risk patients, intensive induction chemotherapy was followed by maintenance chemotherapy until delayed RT was initiated. In the following trial, HIT-SKK92 methotrexate-based chemotherapy was applied. In children with complete remission after three cycles, therapy was finished without irradiation. Otherwise, radiotherapy or salvage chemotherapy was administered.

Results

Twenty-nine children were eligible (age, 3.0 to 37.0 months). All children received chemotherapy. In 15 children, no RT was administered. Four children had tumor progression during chemotherapy and underwent irradiation. In 10 patients, RT was given after chemotherapy. Overall survival (OS) and progression-free survival (PFS) rates after 3 years were 17.2% and 14.9%, respectively. Twenty-four children relapsed (13 at the tumor site only, three at distant site, and eight at both local and distant sites). Positive impact on survival was observed in children with complete resection but without statistical significance. Administration of RT was the only significant predictive factor for OS and PFS. Only one child not having RT survived.

Conclusion

Outcome of infants and babies with stPNET is unsatisfactory. Omission of RT jeopardizes survival, even if intensive chemotherapy is applied. We suggest to limit any delay of RT to a maximum of 6 months even in young children.

Genomic and protein expression profiling identifies CDK6 as novel independent prognostic marker in medulloblastoma

PURPOSE

Medulloblastoma is the most common malignant brain tumor in children. Despite multimodal aggressive treatment, nearly half of the patients die as a result of this tumor. Identification of molecular markers for prognosis and development of novel pathogenesis-based therapies depends crucially on a better understanding of medulloblastoma pathomechanisms.

PATIENTS AND METHODS

We performed genome-wide analysis of DNA copy number imbalances in 47 medulloblastomas using comparative genomic hybridization to large insert DNA microarrays (matrix-CGH). The expression of selected candidate genes identified by matrix-CGH was analyzed immunohistochemically on tissue microarrays representing medulloblastomas from 189 clinically well-documented patients. To identify novel prognostic markers, genomic findings and protein expression data were correlated to patient survival.

RESULTS

Matrix-CGH analysis revealed frequent DNA copy number alterations of several novel candidate regions. Among these, gains at 17q23.2-qter (P < .01) and losses at 17p13.1 to 17p13.3 (P = .04) were significantly correlated to poor prognosis. Within 17q23.2-qter and 7q21.2, two of the most frequently gained chromosomal regions, confined amplicons were identified that contained the PPM1D and CDK6 genes, respectively. Immunohistochemistry revealed strong expression of PPM1D in 148 (88%) of 168 and CDK6 in 50 (30%) of 169 medulloblastomas. Overexpression of CDK6 correlated significantly with poor prognosis (P < .01) and represented an independent prognostic marker of overall survival on multivariate analysis (P = .02).

CONCLUSION

We identified CDK6 as a novel molecular marker that can be determined by immunohistochemistry on routinely processed tissue specimens and may facilitate the prognostic assessment of medulloblastoma patients. Furthermore, increased protein-levels of PPM1D and CDK6 may link the TP53 and RB1 tumor suppressor pathways to medulloblastoma pathomechanisms.

Isochromosome breakpoints on 17p in medulloblastoma are flanked by different classes of DNA sequence repeats

Medulloblastoma is a highly malignant embryonal tumor of the cerebellum that accounts for 20%-25% of all intracranial pediatric tumors. The most frequent chromosomal rearrangement in medulloblastoma is isochromosome 17, or i(17q). Its frequency suggests that it serves an important role in tumor pathogenesis, possibly mediated by the disruption or permanent activation of a gene at the breakpoint. To address this question, we performed a detailed analysis of chromosome 17 DNA copy number from 18 medulloblastomas previously shown to carry an apparent i(17q). We identified two breakpoint regions, one well within band 17p11.2 (n = 16) and a second within the pericentromeric region (n = 2). To map the breakpoints more precisely, we constructed a tiling-path matrix-CGH array covering chromosomal band 17p11.2 to the centromere and utilized it to delineate two small breakpoint intervals mapping at Mb 19.0 and 21.7 in seven of the medulloblastomas and in nine hematological neoplasias with i(17q). The former interval contains two breakpoint clusters that each colocalize with a pair of head-to-head inverted DNA sequence repeats, and the latter maps close to a region of alpha-satellite repeats. No consensus coding sequence localizes in these regions. Together, these data strongly suggest that the effects of i(17q) in medulloblastoma are mediated by gene-dosage effects of genes on 17p or 17q rather than by the disruption or deregulation of a "breakpoint" gene. Furthermore, we identified artifacts introduced in DNA copy number data by cross-hybridization of low-copy repeat sequences and discuss the challenge these can pose in the interpretation of diagnostic microarrays.

Role of radiotherapy in anaplastic ependymoma in children under age of 3 years: Results of the prospective German brain tumor trials HIT-SKK 87 and 92

BACKGROUND AND PURPOSE

To evaluate the outcome of very young children with anaplastic ependymoma after delayed or omitted radiotherapy (RT).

MATERIALS AND METHODS

Children under age of 3 years with anaplastic ependymoma were enrolled in the HIT-SKK 87 trial from 1987. After surgery, low-risk patients (R0, M0) received maintenance chemotherapy until elective RT at age of three. In high-risk patients (R+, M+) intensive induction chemotherapy was followed by maintenance chemotherapy and subsequently delayed RT. If there was, progression radiotherapy started immediately. In the HIT-SKK 92, trial MTX-based chemotherapy was applied. RT was administered in non-responders only.

RESULTS

Thirty-four children with anaplastic ependymoma were eligible (age 1.0-33.0 months). All children received chemotherapy. In 13 children, no RT was administered. Preventive RT after chemotherapy was given in nine, and salvage RT in 12 children. OS and PFS rates after 3-year were 55.9 and 27.3%, respectively. Twenty-five children relapsed. Positive impact on survival was observed in children with higher age, M0-stage, complete resection, and treatment with radiotherapy. Without RT only 3/13, children survived.

CONCLUSION

Delaying RT jeopardizes survival even after intensive chemotherapy. Predominant site of failure is the primary tumor site. RT of the neuraxis should be omitted in localized disease.

Technology insight: Proton beam radiotherapy for treatment in pediatric brain tumors

Tumors of the central nervous system are the most common solid tumor in childhood. Treatment options for childhood brain tumors include radiation therapy, surgery and chemotherapy, often given in combination. Radiation therapy regularly has a pivotal role in treatment, and technological advancements during the past quarter of a century have dramatically improved the ability to deliver radiation in a more focused manner. Improvements in imaging and computing ability led to better targeting of tumor tissue using conventional X-ray therapy. These advances have been harnessed for proton radiation therapy. Proton radiotherapy has special physical characteristics that allow normal tissues to be spared better than even the most conformal photon radiation, and it will reduce the complications from treatment. This review discusses the characteristics of proton radiation, and describes examples of pediatric brain tumor patients who would benefit most from this form of treatment.

Conformal radiotherapy, reduced boost volume, hyperfractionated radiotherapy, and online quality control in standard-risk medulloblastoma without chemotherapy: Results of the French M-SFOP 98 protocol

PURPOSE

Between December 1998 and October 2001, patients <19 years old were treated for standard-risk medulloblastoma according to the Medulloblastome-Société Française d'Oncologie Pédiatrique 1998 (M-SFOP 98) protocol. Patients received hyperfractionated radiotherapy (36 Gy in 36 fractions) to the craniospinal axis, a boost with conformal therapy restricted to the tumor bed (to a total dose of 68 Gy in 68 fractions), and no chemotherapy. Records of craniospinal irradiation were reviewed before treatment start.

RESULTS

A total of 48 patients were considered assessable. With a median follow-up of 45.7 months, the overall survival and progression-free survival rate at 3 years was 89% and 81%, respectively. Fourteen major deviations were detected and eight were corrected. No relapses occurred in the frontal region and none occurred in the posterior fossa outside the boost volume. Nine patients were available for volume calculation without reduction of the volume irradiated. We observed a reduction in the subtentorial volume irradiated to >60 Gy, but a slight increase in the volume irradiated to 40 Gy. No decrease in intelligence was observed in the 22 children tested during the first 2 years.

CONCLUSION

This hyperfractionated radiotherapy protocol with a reduced boost volume and without chemotherapy was not associated with early relapses in children. Moreover, intellectual function seemed to be preserved. These results are promising.

The Effect of Treatment Interruptions in the Postoperative Irradiation of Breast Cancer

OBJECTIVE

There is much evidence for the detrimental effect of treatment interruptions on tumor control, particularly in head and neck cancer. In order to determine the outcome of the treatment interruptions in postoperative irradiation of breast cancer, 853 female patients treated between 1990 and 1999 inclusive were retrospectively analyzed.

METHODS

Locally advanced breast cancer patients who received neoadjuvant chemotherapy were not included in the study. Five hundred and forty-six patients (64%) treated with mastectomy and 307 patients (36%) with breast-conserving surgery were analyzed. A total dose of 50 Gy (46--54 Gy) was given to the chest wall/breast and regional lymph nodes in 1.8- to 2-Gy daily fractions, 5 times per week. A 14-Gy (10- to 20-Gy) photon or electron boost was given to the tumor bed of the patients with breast-conserving surgery. Unplanned treatment interruptions occurred in 741 (87%) of the patients and the median duration of the gaps was 13 days (1--91 days). A total of 348 patients (41%) had no treatment break or interruptions of 1 week or less, whereas 505 patients (59%) had treatment interruptions of more than 1 week. The locoregional control (LC) and overall survival (OS) rates were estimated with the Kaplan-Meier method. A Cox proportional hazard regression model was used to evaluate the influence of host- and treatment-related factors on LC and OS (age, menopausal status, histological subtype, grade, hormonal receptor status, pT stage, pN stage, type of surgery, adjuvant treatment, number of gaps and duration of gaps).

RESULTS

For all patients LC rates for 5 and 10 years were 95 and 87%, respectively, and OS rates were 78% for 5 years and 62% for 10 years. LC rates for the group of patients with no treatment break or interruptions of 1 week or less, for 5 and 10 years were 94 and 90%, whereas the LC rates for 5 and 10 years were 89 and 86%, for the group of patients with interruptions of more than 1 week (p=0.019). Treatment interruptions of more than 1 week and premenopausal status appeared to be independent adverse prognostic factors in multivariate analyses affecting the LC (p=0.043 and p=0.005, respectively). The OS rates for the patients without treatment interruptions or interruptions of 1 week or less were also significantly better than for the patients with treatment interruptions of more than 1 week (p=0.026) in multivariate analyses.

CONCLUSION

Interruptions more than 1 week during postoperative irradiation of breast cancer adversely affect the treatment outcome.

Distinctive clinical course and pattern of relapse in adolescents with medulloblastoma

PURPOSE

To report the clinical course of adolescents with medulloblastoma, with specific emphasis on prognosis and pattern of relapse.

METHODS AND MATERIALS

We retrospectively studied the clinical course and outcomes of children aged 10-20 years with medulloblastoma, treated at centers throughout Canada between 1986 and 2003. To better assess time to relapse, a cohort of patients aged 3-20 years at diagnosis was generated.

RESULTS

A total of 72 adolescents were analyzed. Five-year overall survival and event-free survival rates were 78.3%+/-5.4% and 68.0%+/-6.2%, respectively. Late relapses occurred at a median of 3.0 years (range, 0.3-6.8 years). In univariate analysis, conventional risk stratification and the addition of chemotherapy to craniospinal radiation did not have prognostic significance. Female patients had improved overall survival (p=0.007). Time to relapse increased with age in a linear fashion. After relapse, patients faired poorly regardless of treatment modality. Patients who did not receive chemotherapy initially had improved progression-free survival at relapse (p=0.05).

CONCLUSIONS

Our study suggests that adolescents with medulloblastoma might have a unique prognosis and pattern of relapse, dissimilar to those in younger children. They might benefit from different risk stratifications and prolonged follow-up. These issues should be addressed in future prospective trials.

Epigenetic repression of RASSF1A but not CASP8 in supratentorial PNET (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of childhood

Supratentorial primitive neuroectodermal tumors (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of the CNS represent a biological and clinical enigma, despite advances in both molecular techniques and clinical management for these two rare embryonal brain tumors of childhood. Epigenetic changes hold great potential as possible disease mechanisms and may be manipulated therapeutically. We thus studied aberrant methylation of the genes RASSF1A and CASP8 and its consequence on expression in cell lines and primary tumors using a combination of semiquantitative methylation specific PCR (MSP), bisulfite sequencing and RT-PCR. In all, 17 samples of autopsy-derived normal appearing brain served as controls. Opposed to control tissues 19/24 sPNET and 4/6 AT/RT demonstrated aberrant methylation for the RASSF1A promoter region. Treatment of cell lines using 5-Aza-2'-deoxycytidine (5AZA) alone or in combination with trichostatin A (TSA) succeeded in re-establishing expression of RASSF1A in cell lines derived from a renal rhabdoid, an AT/RT and a medulloblastoma. A 5' CpG-rich region of CASP8 was methylated in normal tissues and in tumors. However, CASP8 showed inconsistent expression patterns in normal and tumor tissues. Our results indicate that aberrant methylation of the RASSF1A promoter region may be of importance in the origin and progression of sPNET and AT/RT while the analysed 5'-CpG rich region of the CASP8 gene does not seem to play an important role in these tumors. Further studies of epigenetic changes in these rare tumors are warranted as their biology remains obscure and treatment efforts have been rather unsuccessfull.

Survival of adults treated for medulloblastoma using paediatric protocols

We retrospectively studied 26 consecutive adults treated for medulloblastoma using paediatric protocols. Between 1987 and 2003, patients 18 years old were given adjuvant chemotherapy consisting of one of two 'paediatric' regimens (depending on the time of presentation) and craniospinal local-boost radiotherapy: regimen A (n = 12), vincristine (VCR), intrathecal and/or intravenous methotrexate and conventional radiotherapy; or regimen B (n = 11) sequencing intensive doses of multiple agents followed by hyperfractionated accelerated radiotherapy (HART). A VCR-lomustine-based maintenance followed both regimens. Three additional patients received a tailored treatment due to their impaired neurological status after surgery. The median age at diagnosis was 26 years (range 18-41 years). With a median follow-up of 46 months, 5-year disease-free and overall survival rates were 65+/-11% and 73+/-10%, respectively, for the series as a whole. All patients who received regimen B (5 of whom had metastatic Chang M2-M3 disease) are alive with no evidence of disease at 39 months. Although the number of patients is limited, our data suggest that the sandwich sequential, moderately intensive chemotherapy in combination with HART is an effective treatment for medulloblastoma in adults, and this approach seems to overcome previously-recognised risk factors.

Standard-Risk Medulloblastoma Treated by Adjuvant Chemotherapy Followed by Reduced-Dose Craniospinal Radiation Therapy: A French Society of Pediatric Oncology Study

Objective

The primary objective of this study was to decrease the late effects of prophylactic radiation without reducing survival in standard-risk childhood medulloblastoma.

Patients and Methods

Inclusion criteria were as follows: children between the ages of 3 and 18 years with total or subtotal tumor resection, no metastasis, and negative postoperative lumbar puncture CSF cytology. Two courses of eight drugs in 1 day followed by two courses of etoposide plus carboplatin (500 and 800 mg/m2 per course, respectively) were administered after surgery. Radiation therapy had to begin 90 days after surgery. Delivered doses were 55 Gy to the posterior fossa and 25 Gy to the brain and spinal canal.

Results

Between November 1991 and June 1998, 136 patients (median age, 8 years; median follow-up, 6.5 years) were included. The overall survival rate and 5-year recurrence-free survival rate were 73.8% ± 7.6% and 64.8% ± 8.1%, respectively. Radiologic review showed that 4% of patients were wrongly included. Review of radiotherapy technical files demonstrated a correlation between the presence of a major protocol deviation and treatment failure. The 5-year recurrence-free survival rate of patients included in this study with all optimal quality controls of histology, radiology, and radiotherapy was 71.8% ± 10.5%. In terms of sequelae, 31% of patients required growth hormone replacement therapy and 25% required special schooling.

Conclusion

Reduced-dose craniospinal radiation therapy can be proposed in standard-risk medulloblastoma provided staging and radiation therapy are performed under optimal conditions.

Medulloblastoma in the second decade of life: a specific group with respect to toxicity and management: a Canadian Pediatric Brain Tumor Consortium Study

BACKGROUND

Most reported data of chemoradiotherapy protocols for the treatment of medulloblastoma describe children who were treated in the first decade of life. To consider the feasibility of this approach in adolescents, the authors studied their clinical course with specific emphasis on toxicity, tolerability, and prognosis.

METHODS

In this retrospective study, the authors examined the toxicity profiles and outcomes of children age 10-20 years with medulloblastoma who were treated at centers throughout Canada between 1986 and 2003. Detailed toxicity data from 2 chemotherapy protocols were collected for teenagers and were compared with data from a group of control patients age 5-10 years.

RESULTS

In total, 72 teenagers were analyzed. Grade >/= 2 ototoxicity and neurotoxicity occurred in 45% and 71% of chemotherapy-treated patients, respectively. Grade 3-4 hematotoxicty occurred in 95% of patients. Toxicity resulted in delay of treatment for 73% of patients and dose modification in 75% of patients, including protocol discontinuation in 25% of patients. Weight loss > 10% was encountered in 73% of patients and required intervention in 45% of patients. Teenagers had significantly more hematotoxicity and neurotoxicity compared with controls on both chemotherapeutic protocols. Ototoxicity was similar in both age groups. Toxicity resulted in significantly more treatment delays and dose modifications in teenager patients compared with controls. The 5-year overall and event-free survival rates (+/- standard deviation) were 78% +/- 6% and 70% +/- 6%, respectively. The mean time (+/- standard deviation) to disease recurrence was 3.2 +/- 2.2 years.

CONCLUSIONS

The increased toxicity rate and high incidence of treatment modifications in this study suggested that current pediatric protocols may require modifications for teenagers with medulloblastoma. The results highlighted several issues that should be addressed in future prospective trials.

Three-year recurrence-free survival in a patient with recurrent medulloblastoma after resection, high-dose chemotherapy, and intrathecal Yttrium-90-labeled DOTA0-D-Phe1-Tyr3-octreotide radiopeptide brachytherapy

BACKGROUND

Most medulloblastomas express high levels of somatostatin type 2 receptors (sst2). DOTA0-D-Phe1-Tyr3-octreotide (DOTATOC) specifically binds sst2 in the low nanomolar range. The cytotoxic effect is mediated by the chelated, beta-emitting, metallic radionuclide Yttrium 90 (90Y). The authors applied this innovative treatment option in a boy age 8 years who presented with a recurrent medulloblastoma of the cauda equina: a prognostically poor condition. Targeted radiotherapy was administered to treat minimal sst2-expressing tumor remnants, which persisted despite conventional and high-dose chemotherapy and intercurrent resection of the lesion.

METHODS

A medulloblastoma arising from the floor of the fourth ventricle had been removed surgically; then, the patient was treated with standard adjuvant chemotherapy and craniospinal irradiation according to the prospective HIT '91 protocol. Complete remission was achieved for 20 months, when a drop metastasis of the cauda equina manifested with sensorimotor lumbosacral deficits and urinary incontinence. After four cycles of neoadjuvant chemotherapy (which consisted of combined ifosfamide, carboplatinum and etoposide), two cycles of high-dose chemotherapy and autologous stem cell transplantation were performed; in between, the responding residual tumor within the lumbosacral nerve fibers was microscopically removed. Thereafter, an Indium-111-DOTATOC test injection indicated sst2-expressing tumor remnants within the cauda equina. Consequently, 4 cycles of [90Y]-DOTATOC (4x562.5 megabecquerels) were injected directly into the cerebrospinal fluid in monthly intervals.

RESULTS

The consolidating intrathecal brachytherapy using [90Y]-DOTATOC was tolerated well. A complete remission was achieved for a 3-year period. The only remaining deficit was urinary incontinence.

CONCLUSIONS

Intrathecal administration of targeted radiopeptide brachytherapy in combination with conventional and high-dose chemotherapy and surgical removal represents a promising new option to treat recurrent medulloblastoma and should be explored further.

Outcome for patients with metastatic (M2–3) medulloblastoma treated with SIOP/UKCCSG PNET-3 chemotherapy

The aim of this study was to determine the outcome for patients with Chang stage M2-3 medulloblastoma (MB) treated with surgery and pre-radiotherapy (RT) chemotherapy (CT). Between 1992 and 2000, 68 patients aged 2.8-16.4 years (median 7.8 years) with M2-3 MB were treated with CT comprising vincristine, etoposide, carboplatin and cyclophosphamide. For 61 patients, CT was followed by craniospinal RT 35 Gy/21 fractions with a posterior fossa (PF) boost, 20 Gy/12 fractions. Twenty-four (35%) irradiated patients received a metastatic boost (mean dose to metastases 47.4 Gy, range 40.0-55.1 Gy). With 7.2-years of median follow-up, overall survival (OS) rates at 3 and 5 years were 50.0% (95% Confidence Interval (CI): 38.1-61.9%) and 43.9% (95% CI: 32.0-55.7%), respectively, event-free survival (EFS) rates at 3 and 5 years were 39.7% (95% CI: 28.1-51.3%) and 34.7% (95% CI: 23.2-46.2%), respectively. Univariate analysis did not demonstrate an impact of age, gender, M stage, extent of resection, RT duration or metastatic boost. For patients commencing RT within 110 days of surgery, EFS was significantly (P=0.04) worse than for those who commenced RT later than this. Response to pre-RT CT was assessable from institutional reports for 44 (65%) patients, and 17 (39%) had a complete response (CR), 15 (34%) a partial response (PR), 4 (9%) stable disease (SD) and 8 (18%) progression. Although CT improved outcome for M0-1 patients in the primitive neuroectodermal tumour (PNET-3) randomised study, and resulted in a high response rate in this study, there has been no apparent improvement in outcome for M2-3 patients when compared with earlier multi-institutional series. Newer approaches such as more intensive CT and RT need to be explored.

Adult medulloblastoma: prognostic factors and response to therapy at diagnosis and at relapse

Adult medulloblastoma is a rare tumor with few retrospective studies published so far. The role of adjuvant chemotherapy or chemotherapy at relapse is unclear. This study reports therapy and outcome in all adult (>or=16 years old) medulloblastoma (n=34) and supratentorial primitive neuroectodermal tumor (PNET) patients (n=2) treated in 2 neuro-oncological centers between 1976 and 2002. The median age was 24.5 years (range 16-76). After resection, 16 patients were treated with craniospinal radiotherapy alone, 20 patients also received adjuvant chemotherapy (8 vincristine, CCNU, cisplatin; 7 methotrexate alone or methotrexate/vincristine-based polychemotherapy; 5 other protocols). Median survival in the whole cohort was 126 months (2+ - 200+months). Five-year and 10-year survival rates were 79 % and 56%. Adjuvant chemotherapy was associated with a non-significant trend to prolonged survival (relative risk (RR) 1.89; p=0.068). The median progression-free survival (PFS) after primary therapy was 83 months. At relapse, 10 of 12 evaluable patients achieved a complete response upon second-line therapy. The median survival times from first (n=17) and second relapse (n=9) were 21 months (0-67+ months; 5/17 without second relapse) and 20 months (1-29 months). Cox regression analysis revealed the infiltration of the floor of the 4(th) ventricle at diagnosis as the only therapy-independent prognostic factor (RR 0.48; p=0.03). In conclusion, adjuvant chemotherapy may prolong survival in adult medulloblastoma patients. Moreover, second-line therapy may be beneficial for these patients. As in pediatric medulloblastoma patients, primary infiltration of the floor of the 4(th) ventricle indicates a poor prognosis.

Feasibility and response to induction chemotherapy intensified with high-dose methotrexate for young children with newly diagnosed high-risk disseminated medulloblastoma

PURPOSE

To evaluate the feasibility of and response rate to an intensified induction chemotherapy regimen for young children with newly diagnosed high-risk or disseminated medulloblastomas.

PATIENTS AND METHODS

From January 1997 to March 2003, 21 patients with high-risk or disseminated medulloblastoma were enrolled. After maximal surgical resection, patients were treated with five cycles of vincristine (0.05 mg/kg/wk x three doses per cycle for three cycles), cisplatin (3.5 mg/kg per cycle), etoposide (4 mg/kg/d x 2 days per cycle), cyclophosphamide (65 mg/kg/d x 2 days per cycle) with mesna, and methotrexate (400 mg/kg per cycle) with leucovorin rescue. Following induction chemotherapy, eligible patients underwent a single myeloablative chemotherapy cycle with autologous stem-cell rescue.

RESULTS

Significant toxicities of this intensified regimen, including gastrointestinal and infectious toxicities, are described. Among the 21 patients enrolled, there were 17 complete responses (81%), two partial responses, one stable disease, and one progressive disease. The 3-year event-free survival and overall survival are 49% (95% CI, 27% to 72%) and 60% (95% CI, 36% to 84%), respectively.

CONCLUSION

This intensified induction chemotherapy regimen is feasible and tolerable. With the majority of patients with disseminated medulloblastoma having M2 or M3 disease at diagnosis, the encouraging high response rate of this intensified induction regimen suggests that such an addition of methotrexate should be explored in future studies.

Leptomeningeal neoplasia: epidemiology, clinical presentation, CSF analysis and diagnostic imaging

The incidence of leptomeningeal metastasis over the past several decades has increased among solid tumor patients and decerased in patients with hematologic malignancies. Improvements in systemic therapies are likely responsible for both changes; solid tumor patients are living longer and, threfore, are at higher risk to develop leptomeningeal tumors while patients with hematologic malignancy have benefitted from more aggressive central nervous system prophylaxis. Regardless, both types of patients present with symptoms referrable to multiple levels of the central nervous system and a careful dignostic approach incorporating cerebrospinal fluid studies and appropriate neuroimaging is critical.

Current treatment of medulloblastoma: recent advances and future challenges

Medulloblastoma (MB) is the most common malignant brain tumor of childhood, yet it makes up only 1% of adult brain tumors. MB is uniquely sensitive to chemotherapy and radiation, but successful surgical resection continues to be an important component of therapeutic success. Progress in the treatment of MB has occurred in multiple areas from improved neurosurgical techniques, refined dosing and delivery of radiation, and optimized chemotherapy. Tumors are currently risk-stratified as average risk or high risk depending on clinical factors such as age, extent of resection, and presence of metastases. Molecular biology is beginning to improve upon clinical prognostication and may soon provide the means to accurately predict response to therapy. Treatment for average-risk MB has achieved a level of success that allows efforts to be focused on the limitation of adverse treatment effects. Therapy for high-risk and relapsed MB has been positively affected by the advent of high-dose chemotherapy with stem cell rescue. In addition, molecular targets are being elucidated and new therapeutic agents are being tested for safety and efficacy. Treatment for this disease has evolved a great deal over the preceding decades, but a great deal of work remains to be done to effect reliable cures while reducing long-term sequelae of therapy.

Radiotherapy for pediatric central nervous system tumors: a regional cancer centre experience

INTRODUCTION

The purpose of this review was to analyze outcomes for pediatric patients treated for more common (non-low grade glioma) primary central nervous system (CNS) tumors at a Regional (tertiary) Cancer Center. Comparison to reported results from other regional centres and results from the contemporary literature were made.

MATERIAL AND METHODS

The records of pediatric patients treated with radiotherapy at the London Regional Cancer Center (LRCC) for more common (non-low grade glioma) primary CNS tumors between 1980 and 2001 were reviewed. Details regarding tumor presentation, treatment and outcome were analyzed.

RESULTS

Eighty-eight patients were eligible for the review. Twenty-nine patients with malignant glioma, 37 patients with medulloblastoma or primitive neuroectodermal tumor (PNET), 15 patients with brainstem glioma, 4 with ependymoma and 3 with germ cell tumors were treated during this time period. Average follow-up for the group was 5 years (range 4 months to 19 years). Five-year overall, progression free and cause specific survival were 45, 42 and 50%, respectively. For patients with malignant glioma median progression free and overall survival was 20 and 29 months. For patients with brainstem glioma median progression free and overall survival was 9 and 13 months. For medulloblastoma, 5-year progression free, and overall survival was 60 and 59%.

CONCLUSIONS

RESULTS of this retrospective review of pediatric patients treated at a regional cancer center for primary CNS tumors (other than low grade glioma) were comparable to contemporary results reported by other Canadian centers and North American co-operative group trials.

New Treatments in Pediatric Brain Tumors

The management of childhood brain tumors is likely to change dramatically during the next few years. Current treatment has improved outcome in some types of brain tumors, but for most patients, survival rates have not changed during the past two decades. Advances in surgery, radiation therapy, and chemotherapy are likely to marginally increase survival, and possibly improve the quality of life for long-term survivors. As the molecular factors underlying childhood brain tumors are better elucidated, molecular-targeted therapy will become a major modality of treatment with the promise of not only increasing the likelihood of survival, but also decreasing treatment-related sequelae.