Family history of cancer and seizures in young children with brain tumors: a report from the Childrens Cancer Group (United States and Canada)

Glioma-related seizures in relation to histopathological subtypes: a report from the glioma international case-control study

BACKGROUND

The purpose of this study was to evaluate the distribution of glioma-related seizures and seizure control at the time of tumor diagnosis with respect to tumor histologic subtypes, tumor treatment and patient characteristics, and to compare seizure history preceding tumor diagnosis (or study enrollment) between glioma patients and healthy controls.

METHODS

The Glioma International Case Control study (GICC) risk factor questionnaire collected information on demographics, past medical/medication history, and occupational history. Cases from eight centers were also asked detailed questions on seizures in relation to glioma diagnosis; cases (n = 4533) and controls (n = 4171) were also asked about seizures less than 2 years from diagnosis and previous seizure history more than 2 years prior to tumor diagnosis, including childhood seizures.

RESULTS

Low-grade gliomas (LGGs), particularly oligodendrogliomas/oligoastrocytomas, had the highest proportion of glioma-related seizures. Patients with low-grade astrocytoma demonstrated the most medically refractory seizures. A total of 83% of patients were using only one antiepileptic drug (AED), which was levetiracetam in 71% of cases. Gross total resection was strongly associated with reduced seizure frequency (p < 0.009). No significant difference was found between glioma cases and controls in terms of seizure occurring more than 2 years before diagnosis or during childhood.

CONCLUSIONS

Our study showed that glioma-related seizures were most common in low-grade gliomas. Gross total resection was associated with lower seizure frequency. Additionally, having a history of childhood seizures is not a risk factor ***for developing glioma-related seizures or glioma.

Family cancer history and risk of brain tumors in children: results of the SEARCH international brain tumor study

OBJECTIVE

To examine whether childhood brain tumors (CBTs) are associated with a family history of brain tumors or other cancers in an international case-control study.

METHODS

Cancers in children's first- and second-degree relatives were ascertained by interview with parents of 620 children with astroglial tumors, 255 with primitive neuroectodermal tumors, 324 with other CBTs, and 2,218 controls from Australia, Canada, France, Israel, Italy, Spain, and the US. These were used with histories of neurofibromatosis or tuberous sclerosis to exclude in subanalyses children with Li-Fraumeni or other hereditary syndromes predisposing to brain tumors.

RESULTS

A first- or second-degree relative of 4% of children with astroglial tumors, 6% with PNET, 5% with other CBTs, and 5% of controls had had a brain tumor. Any potential differences were statistically non-significant, including when focusing on relatives diagnosed in childhood. In the US, where anatomical sites of relatives' other cancers were known, CBT occurrence was not associated with any other specific site. Results were not markedly altered by exclusion of children with hereditary syndromes.

CONCLUSION

Consistent with most prior studies using these methods, we observed no strong relationship between CBT occurrence and cancers in family members.

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

The occurrence of brain tumors in children has been anecdotally associated with an increased cancer incidence among relatives. This study rigorously reviewed the epidemiologic literature regarding family history of cancer in children with brain tumors. Six case-control and 10 cohort studies remained after applying stringent inclusion criteria. Most studies found no significant increase in cancer risk among relatives of childhood brain tumor patients. Those associations that were detected were often of borderline significance or demonstrated wide confidence intervals. There is limited evidence that a family history of cancer is more common among families of childhood brain tumor patients.

[Genetic and epidemiologic aspects of brain tumors in children and adolescents]

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Second malignant neoplasms in five-year survivors of childhood cancer: childhood cancer survivor study

BACKGROUND

Because survival rates among childhood cancer patients are increasing, assessing the risk of second and subsequent malignant neoplasms (SMNs) is ever more important. Using the Childhood Cancer Survivor Study cohort, we identified the risk of SMNS:

METHODS

A retrospective cohort of 13 581 children diagnosed with common cancers before age 21 years and surviving at least 5 years was constructed with the use of data from patients treated at 25 U.S. and Canadian institutions. SMNs were ascertained through self-administered questionnaires and verified by pathology reports. Information on therapeutic exposures was abstracted from medical records. The risk of SMN was evaluated by standardized incidence ratios (SIRs) and excess absolute risk. Poisson multiple regression models were used to assess the impact of host and therapy factors on the risk of developing SMNS: All statistical tests were two-sided.

RESULTS

In 298 individuals, 314 SMNs were identified (SIR = 6.38; 95% confidence interval [CI] = 5.69 to 7.13). The largest observed excess SMNs were bone and breast cancers (SIR = 19.14 [95% CI = 12.72 to 27.67] and SIR = 16.18 [95% CI = 12.35 to 20.83], respectively). A statistically significant excess of SMNs followed all childhood cancers. In multivariate regression models adjusted for therapeutic radiation exposure, SMNs of any type were independently associated with female sex (P<.001), childhood cancer at a younger age (P for trend <.001), childhood Hodgkin's disease or soft-tissue sarcoma (P<.001 and P =.01, respectively), and exposure to alkylating agents (P for trend =.02). Twenty years after the childhood cancer diagnosis, the cumulative estimated SMN incidence was 3.2%. However, only 1.88 excess malignancies occurred per 1000 years of patient follow-up.

CONCLUSIONS

Success in treating children with cancer should not be overshadowed by the incidence of SMNS: However, patients and health-care providers must be aware of risk factors for SMNs so that surveillance is focused and early prevention strategies are implemented.

High incidence of secondary brain tumours after radiotherapy and antimetabolites

BACKGROUND

Brain tumours rarely occur in survivors of childhood acute lymphoblastic leukaemia after cranial radiotherapy. An unusually high frequency of brain tumours seen among children enrolled in one of our leukaemia treatment protocols, Total Therapy Study XII, prompted us to identify the potential causes of this complication.

METHODS

We assessed clinical, biological, and pharmacokinetic features in all 52 children who received prophylactic cranial radiotherapy. We compared the cumulative incidence of brain tumours between subgroups, and with that of 421 children who received radiotherapy in previous studies.

FINDINGS

The incidence of brain tumours among irradiated children (six of 52, 12.8% [SE 5.0]) was high compared with patients in the same study who did not receive radiotherapy (none of 101; p=0.0008) and with other protocols that included cranial radiotherapy (p<0.0001). Of the six children, four had erythrocyte concentrations of thioguanine nucleotide metabolites higher than the 70th percentile for the entire cohort, and three had a genetic defect in thiopurine catabolism. The 8-year cumulative incidence of brain tumour among children with defective versus wild-type thiopurine methyltransferase phenotype was 42.9% (SE 20.6) versus 8.3% (4.7; p=0.0077). This protocol differed from previous protocols, in that more intensive systemic antimetabolite therapy was given before and during radiotherapy.

INTERPRETATION

These data support the elimination of prophylactic radiotherapy for acute lymphoblastic leukaemia except in patients at high risk of central-nervous-system relapse. Underlying genetic characteristics and treatment variables may be associated with an increased risk of radiation-associated brain tumours.

Implications of Potential Cure in Acute Myelogenous Leukemia: Development of Subsequent Cancer and Return to Work

Chemotherapy produces extended remissions, and potential cures, in a small minority of patients with acute myeloid leukemia (AML). We explored whether potentially cured patients were at increased risk of subsequent invasive cancer and were able to return to work. Potentially cured patients were defined as those in first or second complete remission (CR) for at least 3 years based on hazard rates for recurrence or death in CR, which declined sharply after this time. Patients who received allogeneic marrow transplant were excluded. We used questionnaires, phone contact, and chart review to obtain information about subsequent cancer and work status. The number of patients who developed invasive cancer was compared with the number expected based on age, gender, and years of follow-up using the Connecticut Tumor Registry. A total of 215 patients met our criteria for potential cure: 203 in first CR and 12 in second CR (of 1,663 treated between 1965 and December, 1992). At a median of 9.2 years from first or second CR, 163 (76%) remain alive in CR. Fifteen patients developed 18 invasive cancers (expected number of patients, 8.8; observed/expected, 1.70; 95% CI, 0.96 to 2.84; P = .06). Patients initially treated between 1973 to 1979, patients above the potentially cured cohort's median age of 40 years, and those who presented with abnormalities of chromosomes 5 and/or 7 were more likely to develop subsequent cancer, whereas the observed/expected ratio for younger patients was 1.05 (95% CI, 0.13 to 3.80; P = .56). Seventy-four percent of the patients who were working full-time and who were under age 50 at time of treatment for AML have been working full-time in the last 6 months. Only 17 of 56 patients who are currently not working cited physical limitation as the reason. Patients with potentially cured AML are likely to be able to return to work, and at least if younger do not, on average, have an increased risk of invasive cancer.

Implications of Potential Cure in Acute Myelogenous Leukemia: Development of Subsequent Cancer and Return to Work

Chemotherapy produces extended remissions, and potential cures, in a small minority of patients with acute myeloid leukemia (AML). We explored whether potentially cured patients were at increased risk of subsequent invasive cancer and were able to return to work. Potentially cured patients were defined as those in first or second complete remission (CR) for at least 3 years based on hazard rates for recurrence or death in CR, which declined sharply after this time. Patients who received allogeneic marrow transplant were excluded. We used questionnaires, phone contact, and chart review to obtain information about subsequent cancer and work status. The number of patients who developed invasive cancer was compared with the number expected based on age, gender, and years of follow-up using the Connecticut Tumor Registry. A total of 215 patients met our criteria for potential cure: 203 in first CR and 12 in second CR (of 1,663 treated between 1965 and December, 1992). At a median of 9.2 years from first or second CR, 163 (76%) remain alive in CR. Fifteen patients developed 18 invasive cancers (expected number of patients, 8.8; observed/expected, 1.70; 95% CI, 0.96 to 2.84; P = .06). Patients initially treated between 1973 to 1979, patients above the potentially cured cohort's median age of 40 years, and those who presented with abnormalities of chromosomes 5 and/or 7 were more likely to develop subsequent cancer, whereas the observed/expected ratio for younger patients was 1.05 (95% CI, 0.13 to 3.80; P = .56). Seventy-four percent of the patients who were working full-time and who were under age 50 at time of treatment for AML have been working full-time in the last 6 months. Only 17 of 56 patients who are currently not working cited physical limitation as the reason. Patients with potentially cured AML are likely to be able to return to work, and at least if younger do not, on average, have an increased risk of invasive cancer.

Epidemiology of childhood brain tumors

BACKGROUND

Brain tumors comprise more than 20% of all childhood malignancies, and constitute the greatest number of solid pediatric cancers. Incidence rates reported have varied from 2.4 to 3.5/100,000 children, reflecting the impact of modern imaging techniques, the application of diverse investigative methodologies, and the accessibility of the community to health care.

METHODS

Material from patients < 18 years of age was collated from the Manitoba Cancer Foundation Tumor Registry, the personal records of Winnipeg pediatric neurologists, and autopsy data. Patient data were also obtained from hospital charts and operating room log books. Histological sections were examined and classified according to the American Cancer Society by a single neuropathologist. The chi-square test was used for statistical evaluation.

RESULTS

During the seven-year study period, the diagnosis of brain tumor was made in 89 pediatric patients, of which 88 were diagnosed premortem. The overall average annual incidence rate for both sexes was 4.03/100,000 child-years, higher than that previously reported. The male and female average annual incidence rates were 4.2 and 3.7/100,000 child-years, respectively. Tumor type and location were relatively unremarkable, with an expected peak of medulloblastoma occurring in young males. The yearly incidence of tumor occurrence was fairly stable, and the geographic distribution of cases within Manitoba, homogeneous.

CONCLUSION

The highest incidence rates of pediatric brain tumors have been recorded in countries possessing sophisticated universal health care systems, possibly reflecting their efficacy in disease surveillance.

Assessment of environmental and genetic factors in the etiology of childhood cancers: the Childrens Cancer Group epidemiology program

The occurrence of cancer during childhood represents one of the leading causes of death within the pediatric and adolescent age group. It is estimated that approximately 8000 children will be diagnosed annually with cancer in the United States. Epidemiologic research addressing the etiology of childhood cancer has been limited because of the difficulties in identifying a sufficiently large study population. Moreover, the use of retrospectively ascertained childhood cancer cases in epidemiologic investigations has restricted the incorporation of biological and clinical parameters. The Childrens Cancer Group has developed an active program in epidemiologic research, with over a decade of experience demonstrating the feasibility and strengths of conducting analytic epidemiologic studies within a cooperative clinical trials network. The availability of detailed clinical and biologic data on cases diagnosed within the cooperative group facilitates the transfer of state-of-the-art technology to epidemiologic research.

Neurologic and other disorders in relatives of pediatric patients with CNS tumors

Abnormalities of embryogenesis and nervous system development may cause or contribute to the development of childhood brain tumors. To identify genetic or environmental factors that may be associated with etiologies of childhood central nervous system tumors, we examined family histories of 165 children with such tumors for the presence of neurologic disorders, including neural tube defects, mental retardation, seizures, and central nervous system tumors, as well as other cancers and birth defects. Only 1 patient, with the neurofibromatosis-Noonan syndrome, was confirmed to have an underlying syndromic diagnosis associated with central nervous system tumorigenesis. Families of 2 probands with posterior fossa primitive neuroectodermal tumors reported relatives with olivopontocerebellar atrophy. Although increased incidences of study disorders were not identified in this population, it is possible that within individual families one or more of these disorders is related to childhood central nervous system tumorigenesis.

What is the etiology of human brain tumors? A report on the first Lebow conference

Although the conference could not provide a definitive etiologic explanation for the observed increase in incidence of human brain tumors, particularly among the elderly, nevertheless, this interdisciplinary gathering of prominent scientists and clinicians proved invaluable in identifying new avenues of research. Clearly, the puzzle of what causes brain tumors is highly complex, involving links to ionizing/electromagnetic radiation, familial, and dietary factors. The Lebow Conference provided an important scientific framework upon which to build further research studies, and its influence will be felt for years to come.