Trends in Brain Cancer Incidence and Survival in the United States: Surveillance, Epidemiology, and End Results Program, 1973 to 2001.

Sundeep Deorah, M.A.; Charles F. Lynch, M.D., Ph.D.; Zita A. Sibenaller, Ph.D.; Timothy C. Ryken, M.D.

Disclosures

Neurosurg Focus. 2006;20(4):E3 

In This Article

Results

Between 1973 and 2001, 38,453 cases of malignant brain tumor were reported by the nine registries to the SEER database, giving an overall age-adjusted incidence rate of 6.1 cases per 100,000 person-years. The most common histologically confirmed tumor type reported was GBM, which accounted for 16,797 cases, corresponding to an incidence rate of 2.8 cases per 100,000 person-years. The next most common tumor type occurring during the study period was astrocytoma NOS, with an incidence rate of 1.2 cases per 100,000 person-years. The incidence rates of GBM and astrocytoma NOS in 2001 were 3 and 0.3 per 100,000 person-years, respectively.

Figure 1 shows that the age-specific incidence rates of brain cancer during the study period were bimodal, with a small peak in early childhood and a more pronounced peak in the elderly. Incidence rates among children, young adults, and the elderly were 2.5, 5.5, and 17.5 per 100,000 person-years, respectively. The relative risk of brain cancer among the elderly compared with young adults was 3.18 (95% CI 3.09–3.22; Fig. 2). The age-adjusted incidence rate for men was significantly higher than the rate for women (7.4 compared with 5.0 per 100,000), corresponding to a relative risk of 1.48 (95% CI 1.45–1.51). Examination of incidence by race showed that Caucasians were at significantly higher risk for brain cancer than African-Americans (6.7 compared with 3.6 per 100,000); the corresponding relative risk was 1.86 (95% CI 1.78–1.94). Brain cancer was found to occur more frequently among residents of metropolitan counties compared with nonmetropolitan counties (6.5 compared with 4.89 per 100,000). The relative risk of 1.35 (95% CI 1.31–1.38) for metropolitan counties was statistically significant.

Bar graph showing brain cancer incidence per 100,000; population based on data from the nine standard SEER

Bar graph showing relative risks of brain cancer according to sex, age, race, and rurality, based on data from the nine standard SEER registries (1973–2001).

The age-adjusted incidence rates of brain cancer by the year of diagnosis from 1973 to 2001 are demonstrated in Fig. 3. With Joinpoint regression analysis, two distinct trends were observed for this period. The incidence of brain cancer increased from 1973 to 1987 (APC 1.68%; 95% CI 1.22–2.13), followed by a decline thereafter (APC –0.44%; 95% CI –0.84 to –0.03). The results of Join-point regression analyses of brain cancer trends by age, sex, race, and rurality are summarized in Table 1 . The incidence rates of brain cancer decreased among men and women after the years 1986 and 1987, respectively. Although the decline was statistically significant among the women, it did not reach significant levels among the men. Analysis by age revealed that the elderly had the steepest rise in incidence rates until 1985, and the rates have been stable since then. The incidence rates among young adults show a statistically significant decline after 1987. Currently, Caucasians and African-Americans are experiencing falling and rising trends, respectively, both of which are not statistically significant. Although the annual incidence rates are declining in metropolitan counties, they are on the rise in nonmetropolitan counties. Histological diagnoses that have demonstrated rising trends are GBM, oligodendroglioma, anaplastic astrocytoma, medulloblastoma, and mixed glioma; those with falling trends are astrocytoma NOS and malignant glioma (Figs. 4 and 5). Time-trend analysis of GBM revealed that its incidence declined until 1979 (APC –5.58%; 95% CI –8.91 to –2.12), followed by a significant rise until 1991 (APC 2.88%; 95% CI 1.47–4.30; Fig. 4). After 1991, there has been a gradual rising trend that has not reached statistical significance (APC 0.321%; 95% CI –1.00 to 1.66).

Graph showing results of SEER*Stat Joinpoint analysis of brain cancer incidence in the US by year, based on data from the nine standard SEER registries (1973–2001). The arrow indicates the year in which the trend significantly changed; the dashed line indicates the trend.

Graph showing the histological types of brain cancer that demonstrated a rise in annual incidence rates based on data from the nine standard SEER registries. Values in parentheses represent the EAPC.

Graph showing the histological types of brain cancer that demonstrated a decline in annual incidence rates based on data from the nine standard SEER registries.

Table 2 summarizes the five-year relative survival rates for patients with brain cancer. Statistically significant differences in survival rates are noted by sex, race, age, and rurality. The five-year survival rates showed improvement over the study period (21% in the 1970s, 27% in the 1980s, and 31% in the 1990s, p < 0.001). However, for GBM, 1-year relative survival rates showed improvement from only the 1970s to the 1980s (28% compared with 32%, p < 0.001). There is no statistically significant improvement in the survival rate for GBM after the 1980s.

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