Medulloblastoma in childhood: results of radical resection and low-dose neuraxis radiation therapy

The evolution of pediatric neurosurgery: reflection of personal experience of the last half-century

OBJECTIVES

In the past 50 years, pediatric neurosurgery has made tremendous strides, and gained its own identity as a distinct subspecialty. I have personally observed this progress and evolution in pediatric neurosurgery in multiple dimensions, which are described based upon my own experience and reflection.

METHODS

The development and evolutions of multiple domains of pediatric neurosurgery, including neuroimaging, hydrocephalus, pediatric brain tumor, spinal dysraphism, craniosynostosis, vascular malformation, functional neurosurgery and spinal disorders were reviewed and commented on based upon my own experience and reflection.

RESULTS

The field of pediatric neurosurgery has grown in all aspects of diagnosis and therapy owing to the introduction of computers, innovative techniques and technologies and new discoveries of scientific data including molecular investigations.

CONCLUSION

A minimally invasive approach and molecular target therapy are a current trend. The past half century's clinical experience and advances in biomedical knowledge and techniques provide foundation for further improvement in the care of children of the next generation. Prospective artificial intelligence will likely promote further advances in pediatric neurosurgery.

Reduced-volume tumor-bed boost is not associated with inferior local control and survival outcomes in high-risk medulloblastoma

BACKGROUND

Radiotherapy boost to the entire posterior fossa (PF) is standard of care for high-risk (H-R) medulloblastoma patients; the utility of tumor bed (TB)-only boost is unclear. The purpose of this study was to examine the impact of PF versus TB boost volume on tumor control and survival in the H-R medulloblastoma population.

METHODS

Single-institution records for patients with H-R medulloblastoma were reviewed. The median craniospinal irradiation dose was 36 Gy (range, 23.4-45 Gy), and boost doses to either PF or TB were 54 to 55.8 Gy. PF (local) failures were scored as in-field, marginal (between 80% and 95% isodose lines), or distant. Kaplan-Meier methods and Cox proportional hazards were used to assess the impact of radiation boost technique on local control (LC) and survival endpoints.

RESULTS

Thirty-two patients with H-R medulloblastoma were treated between 1990 and 2015, with a median follow-up length of 5.12 years. Twenty-two patients received PF boost, and 10 received TB boost. Patient and disease characteristic were comparable between groups. A total of 11 PF failures occurred, including 3 isolated LFs (2 in the PF and 1 in the TB group). Most PF failures were in-field: three of four in the TB group and six of seven in the PF group; the remainder were marginal failures. TB boost was not associated with inferior LC (hazard ratio [HR] 0.86, log-rank P = 0.81) or overall survival (HR 1.40, P = 0.56) compared with PF boost.

CONCLUSION

Reduced-volume radiotherapy boost to the TB does not appear to compromise LC or survival in patients with H-R medulloblastoma; it may reduce the risk of ototoxicity.

Gestational diabetes exacerbates maternal immune activation effects in the developing brain

Maternal inflammation and diabetes increase the risk for psychiatric disorders in offspring. We hypothesized that these co-occurring risk factors may potentiate each other. To test this, we maternally exposed developing mice in utero to gestational diabetes mellitus (GDM) and/or maternal immune activation (MIA). Fetal mouse brains were exposed to either vehicle, GDM, MIA or GDM+MIA. At gestational day (GD) 12.5, GDM produced a hyperglycemic, hyperleptinemic maternal state, whereas MIA produced significant increases in proinflammatory cytokines and chemokines. Each condition alone resulted in an altered, inflammatory and neurodevelopmental transcriptome profile. In addition, GDM+MIA heightened the maternal inflammatory state and gave rise to a new, specific transcriptional response. This exacerbated response was associated with pathways implicated in psychiatric disorders, including dopamine neuron differentiation and innate immune response. Based on these data, we hypothesize that children born to GDM mothers and exposed to midgestation infections have an increased vulnerability to psychiatric disorder later in life, and this should be tested in follow-up epidemiological studies.

Factors affecting survival of medulloblastoma in children: the changing concept of management

Medulloblastoma (MB) is a type of malignant tumor arising only in the cerebellum that was first defined by Cushing and Bailey in 1920s. In this review paper, we trace the evolution of risk stratification and the correlated changing concept of management in the past years. Outcome analysis of the hospital series of the Taipei Veterans General Hospital, Cheng Hsin General Hospital, and Taipei Medical University Hospital was performed to correlate prognostic indicators with reported studies. The purpose is to provide clues for age-specific and risk-adjusted optimal, effective, but beneficial and protective treatment strategies of these tumors in children.

Treatment developments and the unfolding of the quality of life discussion in childhood medulloblastoma: a review

PURPOSE

To describe how the quality of life (QOL) discussion in childhood medulloblastoma (MB) relates to treatment developments, survival and sequelae from 1920 to 2014.

METHODS

Articles containing "childhood medulloblastoma" and "quality of life" were identified in PubMed. Those containing phrases pertaining to psychological, emotional, behavioral or social adjustment in the title, abstract or keywords were selected. Inclusion of relevant older publications was assured by cross-checking references.

RESULTS

1920-1930s: suction, electro-surgery, kilovolt (KV) irradiation. Survival = months. Focus on operative mortality, symptoms and survival. 1940s: radiotherapy improved. 1950s: chemotherapy and intubation. Survival = years. Opinions oscillated between optimism/awareness of physical sequelae of radiotherapy. 1960s: magnified vision, ventriculo-peritoneal (VP) shunts, megavolt (MV) irradiation. Long-term survival shifted the attention towards neurological problems, disability and carcinogenesis of radiotherapy. 1970s: CT, microscope, bipolar coagulation, shunt filters, neuroanesthesia, chemotherapy trials and staging studies. Operative mortality decreased and many patients (re)entered school; emphasis on neuropsychological sequelae, IQ and academic performance. 1980s: magnetic resonance imaging (MRI), Cavitron ultrasonic aspiration (CUSA), laser surgery, hyper-fractionated radiotherapy (HFRT). Cerebellar mutism, psychological and social issues. 1990s: pediatric neurosurgery, proton beams, stem cell rescue. Reflections on QOL as such. 21st century: molecular genetics. Premature aging, patterns of decline, risk- and resilience factors.

DISCUSSION

QOL is a critical outcome measure. Focus depends on survival and sequelae, determined after years of follow-up. Detailed measurements are limited by time, money and human resources, and self-reporting questionnaires represent a crude measure limited by subjectivity. Therapeutic improvements raise the question of QOL versus cure. QOL is a potential primary research endpoint; multicenter international studies are needed, as are web-based tools that work across cultures.

Appraisal of the current staging system for residual medulloblastoma by volumetric analysis

AIM

This study aims to investigate the accuracy of the current staging system of childhood medulloblastoma by using volumetric image analysis on immediate post-operative MRI scans.

MATERIAL AND METHODS

Tumour volume and maximum cross area of residual medulloblastoma were measured on immediate post-operative MR scans of 37 children operated between 1999 and 2005.

RESULTS

Mean preoperative volume was 32 cm(3) (range 4.5-71.9 cm(3)). Mean post-operative volume was 3.3 cm(3) (range 0-23.3 cm(3)). At mean follow-up of 50.08 months (range 6-129), 15 (40%) patients had died. Cut-off limit for residual post-operative tumour volume employed was maximum cross section of 1.5 cm(2), which corresponds to volume of 1.376 cm(3); 14 patients (38%) had no residual tumour, 7 patients (19%) had less than 1.5 cm(2) and 16 patients (43%) had more than 1.5 cm(2) residual tumour in its maximum cross section area. In three patients (8.2%) there was mismatch between the measured maximum cross section area and volume. In particular, in two patients, the cross section areas were more than 1.5 cm(2) but the residual tumour volumes were less than 1.376 cm(3) (the cross section area overestimated the residual volume) and in one case, the cross section area was less than 1.5 cm(2) but the residual tumour volume was more than 1.376 cm(3) (the cross section area underestimated the residual volume; difference statistically significant, Fisher's exact test, p < 0.01).

CONCLUSIONS

It appears that volumetric measurement of residual medulloblastoma on immediate post-operative MRI scans may further improve the accuracy of staging process.

Childhood medulloblastoma

Among all the childhood central nervous system tumours, medulloblastoma and other neuroectodermal tumours account for 16-25% of cases. The causative factors of medulloblastoma/PNET have not been well established. It is more frequent in boys than in girl and in children than in adults. There was a significant improvement of survival for children diagnosed in 2000-2002 compared to those diagnosed in 1995-1999. The risk of dying was reduced by 30%. Patients are generally divided into risk-stratified schemes on the basis of age, the extent of residual disease, and dissemination. Sixty to 70% of patients older than 3 years are assigned to the average-risk group. High-risk patients include those in the disseminated category, and in North American trials those that have less than a gross or near-total resection, which is arbitrarily defined as 1.5 cm(2) of post-operative residual disease. Current and currently planned clinical trials will:define molecular and biological markers that improve outcome prediction in patients with medulloblastoma and which can be incorporated for front-line stratification of newly defined risk subgroups.

Intraoperative arachnoid and cerebrospinal fluid sampling in children with posterior fossa brain tumors

OBJECTIVE

This study was conducted to determine whether arachnoid tissue or cerebrospinal fluid (CSF) sampling is valuable for risk stratification in children with posterior fossa brain tumors.

METHODS

Arachnoid tissue and CSF from the cisterna magna (CSFCM) was sampled at the time of primary tumor resection. Results were compared with conventional staging methods (M stage) and correlated with patient outcome.

RESULTS

Eighty-three patients were enrolled in the study. Arachnoid infiltration was identified in 11 of 80 (13.8%) and CSFCM was positive in 20 of 77 (26.0%) specimens. Arachnoid infiltration and CSF cytology were found in 20.0% and 44.8%, respectively, for medulloblastoma/pineoblastoma (primitive neuroectodermal tumor), 6.9% and 3.6% for pilocytic astrocytoma, and 0.0% and 33.3% for ependymoma. The 3-year event-free survival (EFS) was negatively influenced by either arachnoid infiltration (40.9% arachnoid positive versus 65.4% arachnoid negative; P = 0.23) or CSFCM positivity (52.6% CSFCM positive versus 67.1% CSFCM negative; P = 0.03). The 3-year EFS for patients with primitive neuroectodermal tumor who had positive arachnoid sampling was 33.3%, compared with 67.3% in patients who had no evidence of arachnoid infiltration (P = 0.26). The 3-year EFS for patients with primitive neuroectodermal tumor who had positive CSFCM was 50.0% compared with 67.5% in patients who had negative cytological analysis of CSFCM (P = 0.07). Arachnoid infiltration and CSF sampling were congruous with M stage in 73.3% and 86.2% of patients, respectively.

CONCLUSION

Intraoperative evidence of arachnoid infiltration or CSFCM dissemination in patients with posterior fossa brain tumors occurs at a variable frequency that is dependent on tumor type, correlates with conventional M stage, and may be predictive of outcome.

Incidence, risks, and sequelae of posterior fossa syndrome in pediatric medulloblastoma

PURPOSE

To investigate the incidence, risks, severity, and sequelae of posterior fossa syndrome (PFS) in children with medulloblastoma.

METHODS AND MATERIALS

Between 1990 and 2007, 63 children with medulloblastoma at Emory University and Children's Healthcare of Atlanta were treated with craniectomy followed by radiation. Fifty-one patients were assigned to a standard-risk group, and 12 patients were assigned to a high-risk group. Five patients had <1.5-cm(2) residual tumor, 4 had >or=1.5-cm(2) residual tumor, and the remainder had no residual tumor. Eleven patients had disseminated disease. Patients received craniospinal irradiation at a typical dose of 23.4 Gy or 36 Gy for standard- or high-risk disease, respectively. The posterior fossa was given a total dose of 54 or 55.8 Gy. Nearly all patients received chemotherapy following cooperative group protocols.

RESULTS

Median follow-up was 7 years. PFS developed in 18 patients (29%). On univariate analysis, brainstem invasion, midline tumor location, younger age, and the absence of radiographic residual tumor were found to be predictors of PFS; the last two variables remained significant on multivariate analysis. From 1990 to 2000 and from 2001 to 2007, the proportions of patients with no radiographic residual tumor were 77% and 94%, respectively. During the same eras, the proportions of patients with PFS were 17% and 39%. Only 4 patients had complete recovery at last follow-up.

CONCLUSIONS

The incidence of PFS increased in the latter study period and is proportional to more aggressive surgery. Children with midline tumors exhibiting brainstem invasion are at increased risk. With the increased incidence of PFS and the permanent morbidity in many patients, the risks and benefits of complete tumor removal in all patients need to be reexamined.

Comparison of Helical Tomotherapy versus Conventional Radiation to Deliver Craniospinal Radiation

The purpose of this study was to investigate whether helical tomotherapy would better dose-limit growing vertebral ring apophyses during craniospinal radiation as compared to conventional techniques. Four pediatric patients with M0 medulloblastoma received tomotherapy craniospinal radiation (23.4 Gy, 1.8 Gy/fx) by continuous helical delivery of 6 MV photons. Weekly blood counts were monitored. For comparison, conventional craniospinal radiation plans were generated. To assist in tomotherapy planning, a cross-sectional growth study of 52 children and young adults was completed to evaluate spine growth and maturation. Vertebral ring apophyses first fused along the posterolateral body-pedicle synostosis, proceeding circumferentially toward the anterior vertebral body such that the cervical and lumbar vertebrae fused early and mid-thoracic vertebrae fused late. For the four pediatric patients, tomotherapy resulted between 2% and 14% vertebral volume exceeding 23 Gy. Conventional craniospinal radiation predicted between 33% and 44% exceeding 23 Gy. Cumulative body radiation doses exceeding 4 Gy were between 50% and 57% for tomotherapy and between 25% and 37% for conventional craniospinal radiation. Tomotherapy radiation reduced neutrophil, platelet, and erythrocyte hemoglobin levels during treatment. Tomotherapy provides improved dose avoidance to growing vertebrae as compared to conventional craniospinal radiation. However, the long-term effects of tomotherapy dose avoidance on spine growth and large volume low dose radiation in children are not yet known.

Desmoplastic Medulloblastoma in a 48-Year-Old Male

Medulloblastoma is a malignant invasive embryonal tumor of the cerebellum with preferential manifestation in children. The peak of occurrence is seven years of age. Seventy percent of medulloblastomas occur in individuals younger than 16. In adulthood, 80% of medulloblastomas arise in the 21-40 years age group. A 48-year-old male patient was admitted to the hospital with complains of headache, ataxia, morning vomiting and difficulty in speech was operated with the diagnosis of presence of mass of 4 x 7 cm size retaining a diffuse homogenous contrast in the posterior fossa. The diagnosis of desmoplastic medulloblastoma was given after histopathological examination. Immunohistochemical examination revealed that neoplastic cells showed staining with neuron-specific enolase and synaptophysin but not with glial fibrillary acidic protein. This lesion showed nodular, reticulin free-zones (pale islands) surrounded by densely packed, highly proliferative cells. The pale regions within the tumor did not contain reticulin fibers. Desmoplastic medulloblastoma is encountered especially in adulthood. This type of tumor rarely occurs beyond the fifth decade of life. We present a case of desmoplastic medulloblastoma in a 48-year-old male.

The molecular pathology of p53 in primitive neuroectodermal tumours of the central nervous system

One hundred and one pre-treatment primary central primitive neuroectodermal tumours were analysed for the expression of p53 protein by immunohistochemistry using the monoclonal antibody DO-7. The staining intensity was classified into four groups: strong, medium, weak and negative and strong staining intensity was associated with the poorest survival. DNA sequencing of the p53 gene was performed in 28 cases representing all four staining groups. Mutations were found in only three of the strong staining tumours suggesting that DNA mutations were not common events and that in the majority of the tumours with over-expressed p53, the protein was likely to be wild-type. Results of immunohistochemistry showed a significantly positive relationship between the expression of p53 and Bax and Bcl-2 proteins, but not Waf-1. Multivariate analyses supported the prognostic value of p53 immunostaining in central primitive neuroectodermal tumours and also of age and gender of patients.

Foreign body reaction to hemostatic materials mimicking recurrent brain tumor. Report of three cases

Chemical agents routinely used in neurosurgery to achieve intraoperative hemostasis can cause a foreign body reaction, which appears on magnetic resonance (MR) images to be indistinguishable from recurrent tumor. Clinical and/or imaging evidence of progression of disease early after surgical resection or during aggressive treatment may actually be distinct features of granuloma in these circumstances. A series of three cases was retrospectively analyzed for clinical, imaging, surgical, and pathological findings, and the consequences they held for further disease management. All patients were boys (3, 3, and 6 years of age, respectively) and all harbored primitive neuroectodermal tumors. Two tumors were located in the posterior fossa and one was located in the right parietal lobe. Two boys exhibited clinical symptoms, which were unexpected under the circumstances and prompted new imaging studies. One patient was asymptomatic and imaging was performed at planned routine time intervals. The MR images revealed circumscribed, streaky enhancement in the resection cavity that was suggestive of recurrent disease. This occurred 2 to 7 months after the first surgery. At repeated surgery, the resected material had the macroscopic appearance of gelatin sponge in one case and firm scar tissue in the other cases. Histological analysis revealed foreign body granulomas in the resected material, with Gelfoam or Surgicel as the underlying cause. No recurrent tumor was found and the second surgery resulted in imaging-confirmed complete resection in all three patients. Because recurrent disease was absent, the patients continued to participate in their original treatment protocols. All patients remain free from disease 34, 32, and 19 months after the first operation, respectively. During or after treatment for a central nervous system neoplasm, if unexpected clinical or imaging evidence of recurrence is found, a second-look operation may be necessary to determine the true nature of the findings. If the resection yields recurrent tumor, additional appropriate oncological treatment is warranted, but if a foreign body reaction is found, potentially harmful therapy can be withheld or postponed.

Low-stage medulloblastoma: final analysis of trial comparing standard-dose with reduced-dose neuraxis irradiation

PURPOSE

To evaluate prospectively the effects on survival, relapse-free survival, and patterns of relapse of reduced-dose (23.4 Gy in 13 fractions) compared with standard-dose (36 Gy in 20 fractions) neuraxis irradiation in patients 3 to 21 years of age with low-stage medulloblastoma, minimal postoperative residual disease, and no evidence of neuraxis disease.

PATIENTS AND METHODS

The Pediatric Oncology Group and Children's Cancer Group randomized 126 patients to the study. All patients received posterior fossa irradiation to a total dose of 54 Gy in addition to the neuraxis treatment. Patients were staged postoperatively with contrast-enhanced cranial computed tomography, myelography, and CSF cytology. Of the registered patients, 38 were ineligible.

RESULTS

The planned interim analysis that resulted in closure of the protocol showed that patients randomized to the reduced neuraxis treatment had increased frequency of relapse. In the final analysis, eligible patients receiving standard-dose neuraxis irradiation had 67% event-free survival (EFS) at 5 years (SE = 7.4%), whereas eligible patients receiving reduced-dose neuraxis irradiation had 52% event-free survival at 5 years (SE = 7.7%) (P =.080). At 8 years, the respective EFS proportions were also 67% (SE = 8.8%) and 52% (SE = 11%) (P =.141). These data confirm the original one-sided conclusions but suggest that differences are less marked with time.

CONCLUSION

Reduced-dose neuraxis irradiation (23.4 Gy) is associated with increased risk of early relapse, early isolated neuraxis relapse, and lower 5-year EFS and overall survival than standard irradiation (36 Gy). The 5-year EFS for patients receiving standard-dose irradiation is suboptimal, and improved techniques and/or therapies are needed to improve ultimate outcome. Chemotherapy may contribute to this improvement.

Common brain tumours in children: diagnosis and treatment

Dramatic advances have been made in the diagnosis of childhood brain tumours thanks to the development of modern imaging techniques. Advances in the management of these tumours have, however, been slow because of the limitations of an aggressive surgical approach and the risks associated with radiotherapy on the growing, and still immature, brain. The role of chemotherapy remains ill-defined in many patients with brain tumours and large variations in practice exist between groups and institutions. This article provides an overview of the most common paediatric brain tumours, mainly gliomas, medulloblastomas, ependymomas, germ-cell tumours and craniopharyngiomas. Considerations regarding the management of brain tumours in very young children are also examined. The long term outcome for children with brain tumours is discussed, stressing the need to focus on quality of life for survivors.

Metastasis stage, adjuvant treatment, and residual tumor are prognostic factors for medulloblastoma in children: conclusions from the Children's Cancer Group 921 randomized phase III study

PURPOSE

From 1986 to 1992, "eight-drugs-in-one-day" (8-in-1) chemotherapy both before and after radiation therapy (XRT) (54 Gy tumor/36 Gy neuraxis) was compared with vincristine, lomustine (CCNU), and prednisone (VCP) after XRT in children with untreated, high-stage medulloblastoma (MB).

PATIENTS AND METHODS

Two hundred three eligible patients with an institutional diagnosis of MB were stratified by local invasion and metastatic stage (Chang T/M) and randomized to therapy. Median time at risk from study entry was 7.0 years.

RESULTS

Survival and progression-free survival (PFS) +/- SE at 7 years were 55%+/-5% and 54%+/-5%, respectively. VCP was superior to 8-in-1 chemotherapy, with 5-year PFS rates of 63%+/-5% versus 45%+/-5%, respectively (P = .006). Upon central neuropathology review, 188 patients were confirmed as having MB and were the subjects for analyses of prognostic factors. Children aged 1.5 to younger than 3 years had inferior 5-year estimates of PFS, compared with children 3 years old or older (P = .0014; 32%+/-10% v 58%+/-4%, respectively). For MB patients 3 years of age or older, the prognostic effect of tumor spread (MO v M1 v M2+) on PFS was powerful (P = .0006); 5-year PFS rates were 70%+/-5%, 57%+/-10%, and 40%+/-8%, respectively. PFS distributions at 5 years for patients with M0 tumors with less than 1.5 cm2 of residual tumor, versus > or = 1.5 cm2 of residual tumor by scan, were significantly different (P = .023; 78%+/-6% v 54%+/-11%, respectively).

CONCLUSION

VCP plus XRT is a superior adjuvant combination compared with 8-in-1 chemotherapy plus XRT. For patients with M0 tumors, residual tumor bulk (not extent of resection) is a predictor for PFS. Patients with M0 tumors, > or = 3 years with < or = 1.5 cm2 residual tumor, had a 78%+/-6% 5-year PFS rate. Children younger than 3 years old who received a reduced XRT dosage had the lowest survival rate.

Medulloblastoma: time-dose relationship based on a 30-year review

PURPOSE

Time-dose relationships have proven important in many cancer sites. This study evaluates the time factors involved in the successful postoperative radiotherapy of medulloblastoma, based on a 30-year experience in a single institution.

METHODS AND MATERIALS

Fifty-three patients with medulloblastoma received postoperative craniospinal radiotherapy with curative intent between 1963 and 1993. Seven patients (13%) underwent biopsy alone, 28 patients (53%) had subtotal excision, and 18 patients (34%) had gross total excision. Eleven patients received adjuvant chemotherapy. The mean posterior fossa dose was 53.1 Gy; most patients received 54.0 Gy (range, 34.3 to 69.6 Gy). For 41 patients receiving once-a-day therapy, the mean dose was 50.6 Gy (range, 34.3 to 56.0 Gy). For 12 patients receiving twice-a-day therapy, the mean dose was 61.8 Gy (range, 52.6 to 69.6 Gy). Minimum follow-up was 2 years, and median follow-up was 10.7 years. Survival, freedom from relapse, and disease control in the posterior fossa were calculated using the Kaplan-Meier method, and multivariate analysis was performed for prognostic factors. Variables related to radiotherapy were examined, including dose to the craniospinal axis, dose to the posterior fossa, fractionation (once-a-day vs. twice-a-day), use of adjuvant chemotherapy, risk group [high (> or =T3b or > or =M1) or low (< or =T3a and M0-MX)], interval between surgery and radiotherapy (excluding patients receiving chemotherapy before radiotherapy), and duration of radiotherapy.

RESULTS

At 5 and 10 years, overall survival rates were 68 and 64%, respectively, and freedom-from-relapse rates were 61 and 52%, respectively. Rates of disease control in the posterior fossa at 5 and 10 years were 79 and 68%, respectively. At 5 years, absolute survival rates after biopsy alone, subtotal excision, and gross total excision were 43, 67, and 78%, respectively (p=0.04), and posterior fossa control rates were 27, 89, and 83%, respectively (p=0.004). Duration of the treatment course was the only radiotherapy-related variable with a significant impact on freedom from relapse and posterior fossa control. For patients whose radiation treatment duration was < or =45 days, posterior fossa control was 89% at 5 years, compared with 68% for those treated for >45 days (p=0.01). Duration of treatment also affected freedom from relapse at 5 years: < or =45 days (76%) compared with >45 days (43%), p=0.004.

CONCLUSION

Our study demonstrates that if adequate doses are used, then radiotherapy treatment duration will significantly affect the outcome in terms of control of disease in the posterior fossa and freedom from relapse. Fractions of at least 1.75 Gy given once a day, or a twice-a-day regimen should yield optimal local control results.

The radiation treatment of medulloblastoma

Following the introduction of CS-RT the survival rate for this malignant tumour rose from zero to approximately 50%. It appears that the major advances over the last twenty years associated with the introduction of CT/MRI, adequate staging, total resection, adjuvant therapy and improved radiation technique has only added 10-20% to the survival rate making it extremely difficult to evaluate the impact of these advances. While radiation treatment is currently omitted or delayed under the age of 36 months, due to enhanced neurocognitive toxicity, and replaced by maintained systemic therapy, the early encouraging results must stand the test of time in order to become standard practice. The treatment of a child with medulloblastoma with radiation treatment remains the corner stone of treatment while additional novel therapies are being developed.

Updated results of a pilot study of low dose craniospinal irradiation plus chemotherapy for children under five with cerebellar primitive neuroectodermal tumors (medulloblastoma)

PURPOSE

Children under 5 years old with medulloblastoma (MB) have a poor prognosis. They are more susceptible to the deleterious effects of craniospinal irradiation (CSART) and have a higher relapse rate when treated with low-dose CSART alone. We, thus, embarked on a prospective trial testing the usefulness of very low dose CSART and adjuvant chemotherapy. This is an update of a previous report on these patients.

METHODS AND MATERIALS

Between January 1988 and March 1990, 10 patients with medulloblastoma were treated using 18 Gy radiation therapy (RT) to the craniospinal axis, a posterior fossa (PF) boost to 50.4-55.8 Gy and chemotherapy consisting of vincristine (VCR) weekly during RT. This was followed by VCR, cis-diamminedichloroplatinum (CDDP), and lomustine (CCNU) for eight, 6-week cycles. Patients between 18 and 60 months of age without evidence of tumor dissemination were eligible for study. Follow-up was available until September 1994 with a median follow-up for living patients of 6.3 years from diagnosis.

RESULTS

Actuarial survival at over 6 years is 70 +/- 20%. Three of the 10 patients relapsed and died. In one patient, the relapse developed in the spine and brain outside the posterior fossa, in the second, concurrently in the posterior fossa, brain and spine, and the third, only in the spine. One surviving child developed a brain stem infarct 4.8 years after diagnosis and has since almost fully recovered. A mean intelligence quotient (IQ) score of 103 in six patients surviving at least 1 year is unchanged from the baseline group score of 107. Five children tested at baseline and 2 years following treatment had IQ scores of 101 and 102, respectively. Six children tested at baseline and at 3 years had IQ scores of 106 and 96, respectively. Excluding the child tested shortly after his brain stem infarct, baseline and 3 year IQ scores were 103 and 97, respectively. Five of the seven long-term survivors grew at rates significantly below their expected velocities during the follow-up period, while the others grew normally. Three patients have received growth hormone, and none have required thyroid replacement.

CONCLUSIONS

These data suggest that medulloblastoma patients can be cured with chemotherapy and reduced doses of craniospinal irradiation. The low doses of CSART given by us in conjunction with cis-platin-based chemotherapy produce minimal neurocognitive damage. Growth velocities in very young children so treated are, however, dramatically reduced. Better means of improving the therapeutic ratio are still needed.

Intra-axial endophytic primitive neuroectodermal tumors in the pons: clinical, radiological, and immunohistochemical aspects in four children

We present the clinical findings, radiological aspects, operative results, and histopathological features of four typical primitive neuroectodermal tumors (PNET) located in the pontine region in children. All the tumors had an endophytic intra-axial growth pattern. All the children had a short history of severe neurological deficits with involvement of the cranial nerves and pyramidal tract. MRI did not reveal any common feature of malignancy. Compared to our successful experience in operations of intra-axial endophytic brainstem tumors in a total of 32 children, the outcome was poor: all 4 children died within 13 months. We conclude that PNET occurring in the pons is not as rare as was believed, and, compared to PNET in other areas the prognosis is worse.

Pathogenesis of irradiation-induced cognitive dysfunction

Neurocognitive dysfunction is a common sequela of cranial irradiation that is especially severe in young children. The underlying mechanisms of this disorder have not been described. The present review describes the role of the hippocampus and the anatomically related cortex in memory function and its marked susceptibility to ischemic and hypoxic injury. Based on studies of animal models of human amnesia and histopathological findings in the irradiated brain, the neurocognitive sequela of cranial irradiation can be seen to be mediated through vascular injury, resulting in ischemia and hypoxia in the hippocampal region. Recognition of the site and mechanisms of this injury may lead to the development of techniques to minimize the risks.

Quality control of low dose craniospinal irradiation for low risk medulloblastoma

Between July 1984 and May 1990, 25 children (median age 9 years) classified as low risk medulloblastoma were treated post-operatively with low dose craniospinal irradiation (25 Gy) followed by a boost to the posterior fossa (total dose 55 Gy), with or without chemotherapy. Simulator and portal films were reviewed for all patients. Doses delivered at the mid cerebral and spinal axis, anterior vertebral body, field junctions and posterior fossa were recalculated and correlated with outcome. Three children were excluded because of inadequate data leaving 22 cases for study. The 5-year actuarial survival is 55%. Nine recurrences and one second tumour (astrocytoma) were observed. Sites of recurrence were either in the posterior fossa (5), in the brain (3), in the spinal axis (1), or combined (2). The dose delivered was within +/- 5% of that prescribed to the brain in 21/22 cases, and to the posterior fossa and the anterior surface of the vertebral body in 17/22 cases. The only patient who received less than 95% of the prescribed dose to the brain (23 Gy) failed in the subfrontal area and olfactory plate. One of the five patients who received less than 95% of the prescribed dose to the posterior fossa (50.3 Gy) failed at the primary site. None of the five patients who received less than 95% of the dose to the spinal axis failed. Quality control of radiation treatment showed that failures could not be correlated with incorrect technique.

Preirradiation chemotherapy including "eight drugs in 1 day" regimen and high-dose methotrexate in childhood medulloblastoma: results of the M7 French Cooperative Study

The aim of this study was to evaluate the feasibility and efficacy of a protocol that includes "sandwich" chemotherapy, that is, chemotherapy alternated with radiotherapy, and reduced doses of supratentorial irradiation in children with medulloblastoma. Between March 1985 and September 1988, 70 successive children with newly diagnosed medulloblastoma from eight centers were treated in this prospective nonrandomized study. Patients were assigned to two risk groups. Group A included patients with macroscopically complete or subtotal excision, no brainstem involvement, no atypical cells in the cerebrospinal fluid, normal myelography, and who were more than 2 years of age. Group B patients encompassed those who did not fit the criteria for Group A. Two children were excluded from analysis after histological review confirmed ependymoma. Thus, a population of 68 children was selected, with 31 in Group A and 37 in Group B. Treatment consisted of two courses of the "eight drugs in 1 day" ("8/1") regimen followed by two courses of high-dose methotrexate (12 g/m2). Radiotherapy was begun during the 7th week after surgery in Group A and during the 5th week in Group B. In patients older than 2 years, the median radiation dose to the posterior fossa, the spinal axis, and the brain was 54 Gy, 36 Gy, and 27 Gy, respectively. Group B patients received postirradiation chemotherapy with four 8/1 courses monthly. The median time from surgery to radiation therapy was 50 days (range 21 to 141 days). One fatality due to chicken pox on Day 102 and one World Health Organization Grade IV infection occurred. The estimated 5- and 7-year disease-free survival (DFS) rates were 62% and 59%, respectively. These were 74% and 62% in Group A and 57% and 57% in Group B. Patient age, extent of resection, and radiation dose to the whole brain had no prognostic value. Patients with metastasis had a nonsignificant trend for a worse prognosis than patients with nonmetastatic disease (7-year DFS 45% vs. 68%, p = 0.11). In Group B, the 7-year DFS rates for children who received more or less than 30 Gy to the brain were 69% and 52% respectively (p = 0.15). There were recurrences in the posterior fossa (37%), spine (20%), and brain (20%). After a review of radiotherapeutic treatments, only one supratentorial failure could be blamed on reduction of the supratentorial radiation dose. This "sandwich" chemotherapy appeared to be feasible and did not show adverse survival data when compared to other series.

Solitary primary lymphoma of the cerebellopontine angle: case report

A 27-year-old woman had a solitary primary B-cell lymphoma that involved the right cerebellopontine angle. The tumor invaded the ipsilateral acoustic nerve and produced profound sensory neural hearing loss. Surgical resection was promptly followed by radiotherapy and a concluding brief chemotherapy treatment. The patient survived 34 months after the initial onset of the disease or 22 months after the combined treatments. Only six lymphomas affecting the cerebellopontine angle, three primary and three secondary, have been recorded. The combination of surgical treatment and radiotherapy appeared to offer encouraging results for primary lymphomas. The differential diagnosis of lymphoma of the cerebellopontine angle includes common acoustic neurilemoma, meningioma, epidermoid tumor, and other rare neoplasms involving this region that required pathological verification to distinguish them.

Medulloblastoma in pediatric age: a single-institution review of prognostic factors

We report a retrospective study of 35 cases of medulloblastoma in pediatric patients treated at our institution during an 18-year period. Ten of the patients were infants (age < 2 years) and 25 were children (age > 2 years). The main factors affecting prognosis were total removal of the tumor (P < 0.01) and tumor stage (P < 0.01). There were no differences between the survival rate of infants and children, infants had a worse prognosis in regard to quality of life than children.

Pattern of recurrence of medulloblastoma after low-dose craniospinal radiotherapy

PURPOSE

We retrospectively evaluated relapse of medulloblastoma after low- or high-dose craniospinal radiotherapy, and after conventional or hyperfractionated posterior fossa irradiation.

METHODS AND MATERIALS

Ninety-two pediatric patients were treated postoperatively since 1970 at the University of California, San Francisco. Until 1989, we employed conventional fractionation with low (< or = 30 Gy) or high-dose craniospinal fields and low-dose (< or = 56 Gy) posterior fossa boosts. Recently, hyperfractionation delivered low- or high-dose to the craniospinal axis and high-dose to the posterior fossa. Most patients treated after 1979 received chemotherapy.

RESULTS

Median follow-up was 70 months. Five-year disease-free survival was 36% (22% for poor-risk vs. 59% for good-risk patients). Five-year overall survival was 52% (43% for poor vs. 68% for good-risk). Neither the dose to the posterior fossa nor the craniospinal axis was statistically related to recurrence. Failure in the posterior fossa occurred despite boosts greater than 56 Gy. Females, over the age of 6 years, had significantly better relapse-free survival than males of the same age. Six of the 54 patients who relapsed were long-term survivors.

CONCLUSIONS

Low-dose craniospinal radiotherapy, where the majority of patients received chemotherapy, was not associated with increased failure. High-dose posterior fossa hyperfractionation did not improve control. Long-term survival was noted in a number of patients after relapse. We recommend 60 Gy or greater with conventional fractions to the primary area, and continued study of low-dose craniospinal irradiation with adjuvant chemotherapy.

Long-term effects of radiation for medulloblastoma on intellectual and physical development. A case report of monozygotic twins

BACKGROUND

Recent advances in treatment have improved the prognosis for medulloblastoma. Although postoperative radiation of the central nervous system (CNS) is widely practiced, late radiation sequelae, especially in long-term survivors, pose a constant risk.

METHODS

To assess the long-term effects of CNS radiation, a monozygotic twin girl with medulloblastoma was compared with her normal twin. Treatment included total removal of the mass, postoperative chemotherapy, and CNS radiation with 47.8 Gy directed to the posterior fossa, 30.2 Gy to the cerebral hemispheres, and 20 Gy to the whole spine.

RESULTS

Not only the radiated patient's spine but also the unradiated upper and lower limbs were shorter than the control subject's. The patient's thyroid hormone level was within normal range; however, thyroid-stimulating hormone was higher than normal. The patient's intellectual ability deteriorated, and cognitive dysfunction has not improved as of 6 years after treatment.

CONCLUSIONS

Treatment systems that do not cause late sequelae affecting physical and intellectual development should be pursued.

Neuropsychological evaluation of children with intracranial tumors: impact of treatment modalities

Antineoplastic treatment has a deleterious effect on intellectual functions, which is mainly attributable to radiotherapy. With the object of determining the neuropsychological disturbances associated with brain irradiation in the child, and to try to differentiate them from the effects caused by the other types of treatment (surgical and chemotherapy) as well as from the effects of the tumor itself, a cross-sectional study was carried out in 25 survivors of medial edge intracranial tumors. In order to monitor the effect of systemic chemotherapy on the cognitive functions, and the effect of prolonged absence from school, two control groups were formed, one made up of subjects treated with chemotherapy for extracranial tumors, and the other of patients with non-malignant chronic disease. Neuropsychological functions were measured using the Spanish version of the Wechsler scale, as well as the following tests: Spreen-Benton, ITPA and TALE scales, Yuste Memory Test, Thurstone Attention Test, and the Rey Complex Figure. In addition to a progressive decline found in the full scale intelligence quotient in children irradiated for intracranial tumors, variance analysis showed that these patients deteriorate mainly in visual attention and memory, but also significantly in verbal fluency and in the Performance Intelligence Quotient and all its subtests, when compared to the control groups. Visual attention and the Wechsler Picture Arrangement and Block Designs, were the tests whose decline correlated with the total radiation administered. The article relates this specific neuropsychological injury with the total brain irradiation dose but also with the structures located in the cone-down fields of irradiation to boost regions in the middle edge intracranial content.

Metastatic medulloblastoma: the experience of the French Cooperative M7 Group

A retrospective analysis was performed to determine the outcome of children with metastatic medulloblastoma given a standardised treatment programme. Of 68 consecutive patients treated in the French M7 protocol for medulloblastoma, 23 presented with metastatic disease. They were uniformly treated with surgery, and the same protocol of chemotherapy and craniospinal radiotherapy. The 7-year relapse-free survival rate is 43% for metastatic patients compared to 68% for patients with localised disease. Survival did not correlate with age, sex, location of metastases, extent of initial surgery and the dose of radiation therapy on the posterior fossa. Survival did correlate with the dose to the cranial field with a threshold dose of 30 Gy. Patients with metastatic disease have a worse prognosis and require more aggressive therapies at initial presentation. The prognostic impact of the different sites of metastatic disease requires further evaluation in cooperative studies.

Is there a danger in delaying radiotherapy in childhood medulloblastoma?

Approximately 45-50% of children with medulloblastoma are cured by conventional surgery and radiotherapy, but survivors may face severe late neuropsychological toxicity. Studies showing good partial responses to platinum-based chemotherapy in relapsed patients and the theoretical possibility of a therapeutic window immediately after surgery have prompted neoadjuvant treatment studies which are ongoing. However, the absolute benefit of chemotherapy for the treatment of medulloblastoma in childhood is, as yet, not proven. There is a danger that chemotherapy may simply delay radiotherapy, and in so doing reduce the radiological impact of this known effective treatment. We report four children with medulloblastoma presenting consecutively to this unit over a 6-month period, whose management was problematic because of either failure to respond to neoadjuvant chemotherapy or their very young age. These cases are discussed in the light of the current literature and future treatment strategies that must seek to improve the therapeutic ratio of multimodality therapy.

Results of a pilot study of low-dose craniospinal radiation therapy plus chemotherapy for children younger than 5 years with primitive neuroectodermal tumors

BACKGROUND

Children younger than 5 years who have posterior fossa (PF) primitive neuroectodermal tumors (PNET) have a poor prognosis. Because the use of low-dose craniospinal radiation therapy (CSRT) alone has been associated with a higher relapse rate in these patients, and because standard dose CSRT is associated with profound late sequelae, the authors embarked on a study using a combination of low-dose CSRT and adjuvant chemotherapy.

METHODS

Between January 1988 and March 1990, ten patients with PF PNET were treated on an institutional pilot trial. The trial included 1800 cGy radiation therapy (RT) to the craniospinal axis, a PF boost to 5040-5580 cGy and chemotherapy consisting of vincristine weekly during RT. This was followed by vincristine, cisplatin, and lomustine for eight cycles administered every 6 weeks. Patients between 18 and 60 months of age without evidence of tumor dissemination were eligible for study. Follow-up is available to October 1992, with a median follow-up of 4 years from diagnosis. All patients have completed therapy.

RESULTS

Actuarial survival at just more than 4 years is 69%. Three of the ten patients have died after experiencing relapse. In one, the relapse developed in the spine and brain outside the PF; in the second, concurrently in the PF, brain, and spine; and in the third, only in the spine. In one of the three, one of two initial cerebrospinal fluid cytologic examinations showed one clump of tumor cells, and the other sample appeared normal. Neuropsychologic testing has been a routine aspect of the study. A mean intelligent quotient (IQ) score of 103 in six patients surviving at least 1 year is unchanged from the baseline group score of 107. Five children have been tested at baseline and at 2 years after RT; for these children, baseline IQ was 101 and 2-year IQ was 102. These results stand in sharp contrast to earlier studies from this institution that found children younger than 7 years at diagnosis showing marked IQ losses after RT at 1 and 2-year follow-up.

CONCLUSIONS

The results of this study suggest that 1800 cGy CSRT in conjunction with the chemotherapy used may produce less neurocognitive damage, perhaps at the expense of relapse along the craniospinal axis. Better means of improving survival without increasing toxicity are needed.

Intracranial tumours in the first year of life. A report on 51 cases

The authors report on 51 infants with intracranial tumours treated in an eleven-year period; these infants represent 13% of the total population of children with intracranial tumours who have been operated on in the same institution during the same period of time. Males (28 cases) were slightly more frequent. Astrocytomas (17 cases), medulloblastomas (12 cases), and ependymal tumours (5 cases) were the commonest histologic types. Signs and symptoms of increased intracranial pressure were by far the most frequent clinical manifestations, followed by seizure disorders. Thirty tumours were localized within the supratentorial, and 21 within the subtentorial compartment. The parasellar region (10 cases) and the lateral cerebral ventricles (8 cases) for the supratentorial tumours, the inferior cerebellar vermis and fourth ventricle (13 cases) for the infratentorial tumours appeared to be the preferred topographic locations. Craniotomies were carried out in 44 infants, with a total or radical removal of the tumour in 19 cases, a subtotal removal in 6 cases, and a partial removal in 17 cases. In 3 cases only a biopsy procedure was performed. Twenty-nine of these patients required an ancillary procedure such as CSF shunting. Three subjects underwent a biopsy procedure and 1 infant the insertion of a CSF shunting device only. Surgery was not performed in 5 cases. Overall, there were two surgical deaths. Two infants died before any surgical treatment could be performed. Radiation therapy was administered to 9 patients when they had reached three years of age. Chemotherapy was given to 21 infants, according to various chemotherapeutic protocols. During the postoperative period 20 deaths (39%) were recorded. Two patients were lost to follow-up. From 1 to 10 years after the operation, 29 patients are still alive, 14 of them (28%) with a normal psychomotor development, 10 (20%) with some neurological or mental deficits, and 5 (10%) with severe psychomotor retardation. There was no apparent correlation in this series between late outcomes and the histological type of the tumour.

Posterior cranial fossa tumours in childhood

We reviewed clinical and CT findings in 133 posterior cranial fossa tumours in children. All had histological diagnosis, apart from 20 cases of brain stem glioma. The majority were intra-axial tumours, including 53 medulloblastomas (40%), 31 cerebellar astrocytomas (23%), 28 brain stem gliomas (21%), 14 ependymomas (11%), and single cases of ganglioglioma, haemangioblastoma and teratoma. Extra-axial tumours formed only 3%, including 2 chordomas and 2 schwannomas. The clinical data and CT findings are reviewed. Cerebellar astrocytoma involved the sexes equally, while medulloblastoma, brain stem glioma, and ependymoma were more common in males. Most cerebellar astrocytomas were in the midline, and presumably arose from the vermis. The frequency of calcification was similar to that in previous reports, being highest in ependymoma (69%), followed my medulloblastoma (29%), cerebellar astrocytoma (17%), and brain stem glioma (8%).

Medulloblastoma in children and in adults: a comparative study

We report on the clinical and pathological characters and factors influencing prognosis in a consecutive series of 20 cases of medulloblastoma presenting in childhood and of 20 cases of the tumour presenting in adulthood. The significant differences which emerged were compared with the findings of the largest published series. Medulloblastoma is more often lateral in site and desmoplastic in histology in adults than in children. On our evidence the age at tumour onset not affect survival.

M4 protocol for cerebellar medulloblastoma: supratentorial radiotherapy may not be avoided

The main goal of the M4 protocol was to evaluate the efficacy of treatment excluding supratentorial radiation in patients with newly diagnosed medulloblastoma. All patients underwent surgical resection and received postoperative chemotherapy. Chemotherapy was adapted to the initial staging and prognostic factors (Group A: good-risk; Group B: poor-risk). Chemotherapy was started early after surgery, and consisted of two courses of the "eight drug in one day" regimen and two courses of high dose methotrexate. Radiotherapy was delayed until 5 (Group B) to 7 (Group A) weeks after the first course of chemotherapy. Radiotherapy was administered only to the posterior fossa and the spinal axis. Only 3/16 patients (18%) are alive and disease-free with a mean follow up of 6 years. The site of progression was supratentorial in 9 out of 13 patients and three patients had spinal and/or cerebrospinal fluid relapses. Only one patient had isolated posterior fossa relapse. The mean time to relapse was 484 days. We conclude that the chemotherapy regimens used in the M4 protocol do not allow the reduction of irradiation fields in patients with cerebellar medulloblastoma. In spite of long-term side effects on neurocognitive functions, supratentorial radiotherapy should remain a major component of medulloblastoma treatment.

Medulloblastoma: tumor biological and clinical perspectives

Medulloblastoma is the most common central nervous system malignancy of childhood, with approximately 350 new cases seen in the United States each year. Although the low incidence of this tumor, compared with adult neoplasms such as breast or colon carcinoma, has limited laboratory and clinical research, recent studies have greatly enhanced our understanding of the biology, phenotype, genotype, and therapy of medulloblastoma. Further efforts to integrate laboratory and clinical studies of this tumor may allow design of novel therapeutic approaches resulting in enhanced disease-free survival.

Low-dose craniospinal radiation therapy for medulloblastoma

At the University of California, San Francisco, 65 children with medulloblastoma of the posterior fossa were treated postoperatively with craniospinal irradiation; the dose to the posterior fossa was 54 Gy. The 26 children initially treated had only radiation therapy, receiving 30 to 40 Gy to the spine and 40 to 50 Gy to the brain. Subsequently, 39 children were treated with low-dose craniospinal irradiation and chemotherapy; 24 to 30 Gy was directed to the whole brain and 24 to 26 Gy to the spinal axis. Chemotherapy generally consisted of procarbazine just before, and hydroxyurea during, radiation therapy. Poor-risk and good-risk patients (defined by tumor resection less than 75% or greater than 75%, positive or negative myelogram, positive or negative cerebrospinal fluid analysis, age less than or greater than 2 years, respectively) were evenly distributed between the low-dose and high-dose craniospinal radiation therapy groups. Median follow-up was 51 months (range, 24 to 228 months). Kaplan-Meier actuarial survival for all patients was 73% at 5 years, 70% at 10 years. Freedom from disease progression was 68% at 5 years, 65% at 10 years. Whereas poor-risk patients treated with low-dose craniospinal irradiation and chemotherapy had a 5-year survival of 58% and a 5-year freedom from disease progression of 39%, those figures in the comparable good-risk patients were 83% and 77%, respectively. For both good-risk and poor-risk patients, the posterior fossa was the primary site of recurrence. Tumors recurred in the frontal region, probably under blocks, in three patients receiving low-dose irradiation and in two receiving the higher dose. Reducing the dose of whole-brain and spinal irradiation and giving chemotherapy did not result in a higher rate of recurrence in the brain or spinal cord. Intellectual and social function appeared better in patients receiving the lower dose. We did not study whether chemotherapy benefitted good-risk patients. Craniospinal axis irradiation at a lower dose than conventionally used does not compromise local control or survival in patients with medulloblastoma, and may reduce toxicity.

Improved survival with the use of adjuvant chemotherapy in the treatment of medulloblastoma

Between 1975 and 1989, 108 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor (MB/PNET) of the posterior fossa were treated at the authors' institution. The patients were managed uniformly, and treatment included aggressive surgical resections, postoperative staging evaluations for extent of disease, and craniospinal radiation therapy with a local boost. Beginning in 1983, children with MB/PNET were prospectively assigned to risk groups; those with "standard-risk" MB/PNET were treated with radiation therapy alone, while those in the "poor-risk" group received similar radiation therapy plus adjuvant chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), vincristine, and cisplatin. The 5-year actuarial disease-free survival rate for all patients treated between 1975 and 1982 was 68%, and 73% when patients who died within 2 weeks after operation were excluded. This survival rate was statistically better for patients treated after 1982 (82%) compared to those treated between 1975 and 1982 (49%) (p less than 0.004). There was no difference in disease-free survival rates over time for children with standard-risk factors; however, there was a significant difference in the 5-year survival rate for poor-risk patients treated prior to 1982 (35%) compared to those treated later (87%) (p less than 0.001). For the group as a whole, a younger age at diagnosis correlated with a poorer survival rate; however, this relationship between age and outcome was significant only for children treated before 1983 (p less than 0.001). These results demonstrated an encouraging survival rate for children with MB/PNET, especially those treated with aggressive surgical resection followed by both radiation therapy and chemotherapy. The results strongly suggest that chemotherapy has a role for some, and possibly all, children with MB/PNET.

A newly designed radiation port for medulloblastoma to prevent metastasis to the cribriform plate region

Nine children with medulloblastoma were treated at Chiba University Hospital from 1977 to 1983. Of these cases, metastases to the cribriform plate region were found in two cases. Portal film showed that cribriform-plate region was not included in a conventional whole-brain radiation port to shield the eyes. Since 1983, we have applied a newly designed radiation port to treat childhood medulloblastoma. The new method consists of two parallel, opposed, lateral ports including the cribriform plate and the first two cervical vertebrae, similar to Pinkel's method. It has been confirmed that this method covers completely the whole brain and is safe for the lens. A characteristic of our method is that the landmark of the lower margin of the radiation port can be easily delineated on the patient's face. We believe that this method contributes to the treatment of medulloblastoma.