Trends in incidence of primary brain tumors in the United States, 1985-1994.

Brain tumor incidence has increased over the last 20 years in all age groups, both overall and for specific histologies. Reasons attributed to these increases include increase in lymphoma due to HIV/AIDS, introduction of computed tomography/magnetic resonance imaging, and changes in coding/classification. The purpose of this study was to describe overall and histologic-specific incidence trends in a population-based series of primary benign and malignant brain tumors. Data from the Central Brain Tumor Registry of the United States from 1985 through 1994 were used to determine incidence trends in the broad age groups 0-19, 20-64, and > or = 65 years, both overall and for selected histologies. Poisson regression was used to express trends as average annual percentage change. Overall, incidence increased modestly (annual percentage change 0.9%, 95% confidence interval, 0.4, 1.4). When lymphomas were excluded, this result was not statistically significant (annual percentage change 0.5%, 95% confidence interval, -0.1, 1.1). Specific histologies that were increasing were lymphomas in individuals aged 20 to 64 years and in males aged 65 years or older, ependymomas in the population aged 20 to 64 years, nerve sheath tumors in males, and pituitary tumors in females. Increases that were not specific to any population subgroup were seen for glioblastoma, oligodendrogliomas, and astrocytomas, excluding not otherwise specified (NOS) tumors. Corresponding decreases were noted for NOS, astrocytoma NOS, and glioma NOS. Increasing incidence trends for lymphomas were consistent with previous literature. Improvements in diagnostic technology in addition to changes in classification and coding were likely to be responsible for decreases seen in incidence of NOS subgroups and corresponding increases in glioma subgroups. In contrast, the increases identified for ependymomas, nerve sheath tumors, and pituitary tumors were less likely to be artifacts of improvements in diagnosis, and they warrant further study.

The contribution of nonmalignant tumors to CNS tumor incidence rates among children in the United States.

OBJECTIVES: According the U.S. National Cancer Institute (NCI), the incidence rate of primary malignant central nervous system (CNS) neoplasms among children is about 30 per million person-years. This rate, however, underestimates the true burden of CNS tumors because nonmalignancies are not included in the NCI case reporting system. Intracranial tumors, to an extent regardless of their histological behavior, can have a malignant clinical course and result in a high degree of morbidity and mortality. The purpose of this report is to estimate the contribution that nonmalignant tumors have on the overall incidence of CNS tumors in children. METHODS: Population-based data from the Central Brain Tumor Registry of the United States were analyzed. Included in the analysis were children aged 0-19 years who were diagnosed with a primary CNS tumor from 1990-93 (N = 1133). RESULTS: The inclusion of nonmalignancies increased the CNS tumor incidence rate by 28% from 29.4 to 37.6 per million person-years. The increases were 17% for children aged 0-4 years, 17% for children aged 5-9 years, 31% for children aged 10-14 years and 57% for adolescents aged 15-19 years. Differences in patterns between malignant and nonmalignant tumor occurrence by sex, histology, and location were also observed. CONCLUSION: Because of the potentially profound adverse health effects on children who experience CNS tumors, the systematic collection of both malignancies and nonmalignancies is consistent with the mission of public health surveillance. Without such population-based data, analytic epidemiologic studies to evaluate disease etiology and assess disease consequences are greatly hindered.

Descriptive epidemiology of primary brain and CNS tumors: results from the Central Brain Tumor Registry of the United States, 1990-1994.

The Central Brain Tumor Registry of the United States (CBTRUS) obtained 5 years of incidence data (1990-1994)--including reports on all primary brain and CNS tumors--from 11 collaborating state cancer registries. Data were available for 20,765 tumors located in the brain, meninges, and other CNS sites, including the pituitary and pineal glands. The average annual incidence was estimated at 11.5 cases per 100,000 person-years. The higher incidence of tumors in male patients (12.1 per 100,000 person-years) than in female patients (11.0 per 100,000 person-years) was statistically significant (P < 0.05); the higher incidence in whites (11.6 per 100,000 person-years) compared with blacks (7.8 per 100,000 person-years) was statistically significant (P < 0.05). The most frequently reported histologies were meningiomas (24.0%) and glioblastomas (22.6%). Higher rates for glioblastomas, anaplastic astrocytomas, oligodendrogliomas, anaplastic oligodendrogliomas, ependymomas, mixed gliomas, astrocytomas not otherwise specified, medulloblastomas, lymphomas, and germ cell tumors in male than in female patients were statistically significant (P < 0.05), with relative risks (RR) ranging from 1.3 to 3.4. Meningiomas were the only tumors with a significant excess in females (RR = 0.5). We noted higher occurrence rates in whites than in blacks for the following histologies: diffuse astrocytomas, anaplastic astrocytomas, glioblastomas, oligodendrogliomas, ependymomas, mixed gliomas, astrocytomas NOS, medulloblastomas, nerve sheath tumors, hemangioblastomas, and germ cell tumors, with RRs ranging from 1.5 to 3.4. Racial differences in occurrence rates were not observed for predominately benign meningiomas or pituitary tumors. This study represents the largest compilation of data on primary brain and CNS tumors in the United States. Standard reporting definitions and practices must be universally adopted to improve the quality and use of cancer registry data.