The number of reported brain tumors from the participating registries is listed by state in Table 2. Over 42,500 tumors were reported to CBTRUS in a combined population of 61.5 million that represents approximately 23% of the U.S. population. The overall percent of benign tumors (38%) varied considerably by state (range: 23-55%). Eighty-two percent of all tumors had a histologically confirmed diagnosis, with substantial regional variation (state range: 73-99%).

The overall incidence rate for primary brain and central nervous system tumors was 12.7 per 100,000 person-years adjusted with the year 2000 standard (Table 3). The incidence rates by tumor behavior and state are shown in Figure 2. The total state incidence rates (adjusted using the Year 2000 standard) ranged from 9.6 to 19.5 per 100,000 person-years. The state rates for the malignant tumors are much less variable than the reported rates for the non-malignant tumors suggesting greater consistency in reporting of the malignant tumors. The state variation shown here, especially in reported incidence rates for the benign tumors, likely reflects differences in registry reporting practices including case ascertainment. A more detailed discussion of state reporting differences is available⁹.

The distribution of tumors by site is shown in Figure 3. The majority of tumors (61%) are located within the brain. Other CNS tumors, including meninges represent about 31% of all tumors reported to CBTRUS. The pituitary and pineal glands account for about 8% of tumors reported to CBTRUS.

The distribution by histology is shown in Table 4 and Figure 4. The most frequently reported histology is a predominately benign tumor meningioma, which account for over 25% of all tumors, followed closely by glioblastomas and astrocytomas. The predominately benign nerve sheath tumors and pituitary adenomas/carcinomas account for 7% and 6% of all tumors respectively.

The mean age of diagnosis for all primary brain tumors is 54 years (Table 4). The histology-specific mean ages range from 16 to 63 years. Pilocytic astrocytomas, medulloblastomas, and germ cell tumors have a mean age of onset under 20 years of age. Meningiomas and glioblastomas are diagnosed at older ages. The incidence rates by histology and gender are presented in Table 5. Rates for all primary brain tumors combined are higher among males than females. Rates for most histologies are higher in males or comparable to the rates in females with the notable exception of meningiomas that are twice as common in women. Incidence rates by histology and race are shown in Table 6. Overall rates are higher in Caucasians as compared to African-Americans. The age-specific rates by histology are presented in Table 7. The incidence for all brain tumors is highest among the 75-84 year olds. However, the different histologies have different age distributions as shown in this table. The histologic-specific differences in brain and CNS tumor distribution by age, gender, and race suggest that these tumors have different causes.

Brain tumors are the second most common malignancy among children¹⁰. About 8% of the tumors reported to CBTRUS occurred in people under the age of 20 years. The incidence of the most common childhood tumors is shown in Table 8 and the age-specific rates are shown in Table 9. Among the younger population brain tumors are slightly more common in boys. The most common histologies in the younger age group include embryonal tumors (medulloblastomas) and pilocytic astrocytomas that together account for over 30% of all childhood brain tumors. (Figure 5)

Malignant Brain Tumor Rates: Incidence, Mortality, and Survival

State incidence and mortality rates for primary malignant brain and CNS tumors are shown in Table 10. These rates are adjusted using the 1970 U.S. standard population. The 1993-1997 mortality rates by gender are available for all 50 states. Incidence rates for most states were available from the same time period with a few exceptions. These data were obtained from the most recent Cancer Incidence in North America publication available at http://www.naaccr.org⁶.

Survival estimates by tumor location, histology, and age at diagnosis are presented in Tables 11, 12, and 13 respectively. Survival is poorer for tumors located in the upper regions of the brain (Table 11). Patients with tumors in the meninges and the pituitary have better five-year survival rates. The two-, five-, and ten-year observed and relative survival rates by histology are shown in Table 12. There is a large variation in survival estimates between tumor histologies. Five-year survival rates exceed 85% for pilocytic astrocytomas but are less than 5% for glioblastomas. The estimated five- and ten-year relative survival rates for malignant brain tumors are 27% and 23% respectively. Survival generally decreases with older age at diagnosis (Table 13). Children and young adults have better survival for most histologies.

Histology-specific summary information