Collins' law. Prediction of recurrence or cure in childhood medulloblastoma?

Long-term outcome of posterior fossa medulloblastoma in patients surviving more than 20 years following primary treatment in childhood

The aim of the study was to analyze the long-term outcome (>20 years) after treatment of posterior fossa medulloblastoma (MB) in childhood. We analyzed data from patients treated for posterior fossa MB between 1974 (introduction of the first international treatment protocol in Norway) and 1987 (when use of radiotherapy was abandoned in children under 4 years of age). Out of 47 children, 24 survived >20 years. At the time of analysis, 16 patients (median age 41 years, range 32–52) were alive (median follow-up 34 years, range 30–42), while 8 patients died 22–41 years (median 31 years) after primary treatment: one late death (after 22 years) was due to tumor recurrence whilst other 7 deaths (after 23 to 41 years) were related to the detrimental effects of the treatment (secondary tumors, stroke, severe epilepsy and depression). Observed 20- and 30-year survival rates were 51% and 44%, respectively. Despite successful treatment of MB in childhood and satisfactory tumor control during the first 20 years following primary treatment, our data indicates that even long-term survivors may die from tumor recurrence. However, the main factors causing late mortality and morbidity in long-term survivors seem to be the complications related to radiotherapy given in childhood.

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.

Collins' law revisited: can we reliably predict the time to recurrence in common pediatric tumors?

Collins' law states that the period of risk for tumor recurrence is the age of the child at diagnosis plus 9 months. The purpose of this study is to validate this rule through a retrospective review of common pediatric tumors seen at 1 institution. Inclusion criteria for this study included an age at diagnosis of < 16 years old, minimum follow-up time of the Collins risk period (CRP) if child did not relapse and treatment with curative intent. The records of 424 children seen and treated for neuroblastoma (n = 98), Wilms tumor (n = 86), rhabdomyosarcoma (n = 82), medulloblastoma (n = 59), Ewing sarcoma (n = 43), ependymoma (n = 25), supratentorial PNET (n = 22), and synovial sarcoma (n = 9) from 1960 to 2001 were reviewed. CRP was calculated using the age of child at initial diagnosis plus 9 months. The median follow-up time was 164 months (range, 11-484 months), while the median follow-up/CRP ratio was 4.89 (range, 1.0-48.0). A total of 183 of 424 (43.2%) patients relapsed, with 180 (98.4%) relapses occurring during the CRP. Relapses beyond the CRP were seen in 3 young children (ages 7 months, 24 months, and 2 weeks at initial diagnosis) with a diagnosis of Wilms tumor (n = 2) and supratentorial PNET (n = 1) at 1, 3, and 26 months post-CRP. Collins' law is a useful and simple way of predicting risk period for relapse in the tumor types studied.

MYCC and MYCN oncogene amplification in medulloblastoma. A fluorescence in situ hybridization study on paraffin sections from the Children's Oncology Group

CONTEXT

Brain tumors are the most common solid tumor in childhood, and medulloblastoma is the most common malignant brain tumor in this age group. Cytogenetic abnormalities that have been described in childhood medulloblastoma include loss of 17p, amplification of MYCC (c-myc), amplification of MYCN (N-myc), and isochromosome 17q. Data on these tumors indicate that the frequency of MYCC amplification is 5% to 10%. Fluorescence in situ hybridization is a powerful tool for investigating these features on archival material.

OBJECTIVES

To determine if intratumoral heterogeneity exists for MYCC and MYCN in medulloblastomas and if tumors with amplified MYCC or MYCN exhibit consistent histologic patterns.

DESIGN

In this fluorescence in situ hybridization study, we investigated the frequency and prognostic significance of MYCC and MYCN amplification in 77 medulloblastomas derived from the Children's Oncology Group.

RESULTS

MYCC amplification occurred in only 4 (5.2%) of 77 tumors. The 4 patients died of clinically aggressive neoplasms within 7 months of diagnosis. Similarly, 4 of 77 patients' tumors were found to exhibit MYCN amplification, but survival data are incomplete at present, therefore prognostic significance cannot be characterized.

CONCLUSIONS

These data establish the frequency of MYCC amplification in a large cohort of children with medulloblastoma and further suggest that MYCC amplification may be a marker of poor prognosis. Intratumoral heterogeneity was identified for these oncogenes in that 1 patient's tumor exhibited evidence of both MYCN and MYCC amplification, and this patient experienced a shortened survival time.