Family history of cancer among children with brain tumors: a critical review

The Epidemiology of Brain and Spinal Cord Tumors

CNS tumors are a diverse group of neoplasms that emerge from a variety of different CNS cell types. These tumors may be benign, malignant, or borderline in nature. The majority of high grade glial tumors are fatal, with the exception of pilocytic astrocytoma. Primary malignant CNS tumors occur at a global annual rate of 2.1 to 5.8 per 100,000 persons. Males are more likely to develop malignant brain tumors than females, whereas benign meningiomas are more common in adult females. Additionally, gender inequalities in non-malignant tumors peak between the ages of 25 and 29 years. Only a small number of genetic variants have been associated with survival and prognosis. Notably, central nervous system (CNS) tumors exhibit significant age, gender, and race variation. Race is another factor that affects the incidence of brain and spinal cord tumors. Different races exhibit variation in terms of the prevalence of brain and CNS malignancies. This chapter discusses ongoing research on brain and spinal cord tumor epidemiology, as well as the associated risks and accompanied disorders.

Pediatric Brain Tumors: Descriptive Epidemiology, Risk Factors, and Future Directions

Brain tumors are the most common solid tumors in children and remain a significant contributor to death by disease in this population. Pediatric brain tumors (PBT) are broadly classified into two major categories: glial and neuronal tumors. Various factors, including tumor histology, tumor location, and demographics, influence the incidence and prognosis of this heterogeneous group of neoplasms. Numerous epidemiologic studies have been conducted to identify genetic and environmental risk factors for these malignancies. Thus far, the only established risk factors for PBTs are exposure to ionizing radiation and some rare genetic syndromes. However, relatively consistent evidence of positive associations for birth defects, markers of fetal growth, advanced parental age, maternal dietary N-nitroso compounds, and exposure to pesticides have been reported. The genetic variants associated with susceptibility to PBTs were predominantly identified by a candidate-gene approach. The identified genetic variants belong to four main pathways, including xenobiotic detoxification, inflammation, DNA repair, and cell-cycle regulation. Conducting large and multi-institutional studies is warranted to systematically detect genetic and environmental risk factors for different histologic subtypes of PBTs. This, in turn, might lead to a better understanding of etiology of PBTs and eventually developing risk prediction models to prevent these clinically significate malignancies.

Germline SUFU mutation carriers and medulloblastoma: clinical characteristics, cancer risk, and prognosis

Background

Germline mutations of suppressor of fused homolog (SUFU) predispose to sonic hedgehog (SHH) medulloblastoma. Germline SUFU mutations have been reported in nevoid basal cell carcinoma syndrome (NBCCS), but little is known about the cancer risk and clinical spectrum.

Methods

We performed a retrospective review of all patients with medulloblastoma and a germline SUFU mutation in France.

Results

Twenty-two patients from 17 families were identified with medulloblastoma and a germline SUFU mutation (median age at diagnosis: 16.5 mo). Macrocrania was present in 20 patients, but only 5 met the diagnostic criteria for NBCCS. Despite treatment with surgery and chemotherapy, to avoid radiotherapy in all patients except one, the outcome was worse than expected for SHH medulloblastoma, due to the high incidence of local relapses (8/22 patients) and second malignancies (n = 6 in 4/22 patients). The 5-year progression-free survival and overall survival rates were 42% and 66%. Mutations were inherited in 79% of patients, and 34 additional SUFU mutation carriers were identified within 14 families. Medulloblastoma penetrance was incomplete, but higher than in Patched 1 (PTCH1) mutation carriers. Besides medulloblastoma, 19 other tumors were recorded among the 56 SUFU mutation carriers, including basal cell carcinoma (BCC) in 2 patients and meningioma in 3 patients.

Conclusion

Germline SUFU mutations strongly predispose to medulloblastoma in the first years of life, with worse prognosis than usually observed for SHH medulloblastoma. The clinical spectrum differs between SUFU and PTCH1 mutation carriers, and BCC incidence is much lower in SUFU mutation carriers. The optimal treatment of SUFU mutation-associated medulloblastoma has not been defined.

Childhood brain tumor epidemiology: a brain tumor epidemiology consortium review

Childhood brain tumors are the most common pediatric solid tumor and include several histologic subtypes. Although progress has been made in improving survival rates for some subtypes, understanding of risk factors for childhood brain tumors remains limited to a few genetic syndromes and ionizing radiation to the head and neck. In this report, we review descriptive and analytical epidemiology childhood brain tumor studies from the past decade and highlight priority areas for future epidemiology investigations and methodological work that is needed to advance our understanding of childhood brain tumor causes. Specifically, we summarize the results of a review of studies published since 2004 that have analyzed incidence and survival in different international regions and that have examined potential genetic, immune system, developmental and birth characteristics, and environmental risk factors. Cancer Epidemiol Biomarkers Prev; 23(12); 2716-36. ©2014 AACR.

Childhood central nervous system tumors at MAHAK's Pediatric Cancer Treatment and Research Center (MPCTRC), Tehran, Iran

PURPOSE

As central nervous system (CNS) tumors account for second most common childhood malignancies and the first cause of mortality in children with cancer, improving treatment modalities can lead to increase the health care of patients. In this study, we examined the prevalence of childhood brain tumors in patients who referred to MAHAK's Pediatric Cancer Treatment and Research Center (MPCTRC) for treatment.

METHODS

A retrospective review of all children less than 15 years old with a CNS histologically proven tumor, who presented to MPCTRC from April 2007 to April 2010, was performed. Data was analyzed by SPSS version 19 with Kolmogorov-Smirnov and Chi-square tests.

RESULTS

There were 198 (124 boys) children eligible for the study. The majority of the tumors were infratentorial (n = 134), and the rest were supratentorial (n = 60) and spinal (n = 4) cases. The median age was 6.11 ± 3.65 years old. Medulloblastoma (n = 66), low-grade glioma (n = 52), and high-grade glioma (n = 40) were the most common tumors. The mean duration of follow-up was 21 months. At the time of this analysis, there were 105 (53 %) children alive, 82 (41.4 %) deaths, and 11 (5.6 %) lost for follow-up. The survival rate was 51.68 ± 5.22 %.

CONCLUSIONS

In contrast of high rate of death in this study, other general characteristics can serve as benchmark for improving our care for children with brain tumors in Iran.

[Epidemiology of glioblastoma]

An increasing incidence of glioblastoma has been observed over the last 30 years. Improvements in diagnostic tools such as CT scans and MRI, changes observed in histological classifications, and adjustments in neurosurgical practices have contributed substantially to this increase. Moreover, the aging of the population and the increasing occurrence of glioblastoma beyond 60 years of age are additional explanations. In Gironde (France), where a specialized registry has been established, the annual incidence of glioblastoma is 4.96/100,000. Wide geographic variations are observed, possibly linked to ethnicity. However, the role of intrinsic and/or extrinsic factors cannot be ruled out. Comparing data between registries is difficult and requires taking into account periods of recruitment and diagnostic tools. Ethnicity, age, sex, hereditary syndromes, some constitutive polymorphisms, and brain irradiation are the established risk factors Allergies or asthma, certain viral infections, autoimmune diseases, nonsteroidal anti-inflammatory drug intake, substitutive hormonal therapy, and dietary antioxidant intake are the established protective factors. Many studies on electromagnetic fields - in particular cellular phones - pesticides, solvents, and other factors have been published. Until now, the results are discordant or are not confirmed because of methodological limitations. Future studies combining constitutive polymorphisms and exposure assessment are likely to provide consistent and important data that will improve our knowledge in the epidemiology of glioblastoma.

[Epidemiology of primary brain tumor]

Two main approaches are generally used to study the epidemiology of primary brain tumors. The first approach is to identify risk factors, which may be intrinsic or related to external causes. The second main approach is descriptive. Intrinsic factors potentially affecting risk include genetic predisposition and susceptibility, gender, race, birth weight and allergy. Radiation exposure is the main extrinsic factor affecting risk. A large body of work devoted, among others, to electromagnetic fields and especially cellular phones, substitutive hormonal therapy, pesticides, and diet have been published. To date, results have been discordant. Descriptive epidemiological studies have reported an increasing annual incidence of primary brain tumors in industrialized countries. The main reasons are the increasing age of the population and better access to diagnostic imaging. Comparing incidences from one registry to another is difficult. Spatial and temporal variations constitute one explanation and evolutions in coding methods another. In all registries, weak incidence of primary brain tumors constitute a very important limiting factor. Renewed interest from the neuro-oncological community is needed to obtain pertinent and essential data which could facilitate improved knowledge on this topic.