Cancers of the brain and CNS: global patterns and trends in incidence

Abstract

Background: Cancers of the brain and CNS constitute a group of rare and heterogeneous tumors. Increasing incidence in Western populations has been linked to improvements in diagnostic technology, although interpretation is hampered by changes in diagnosis and reporting. The present study examines geographic and temporal variations in incidence rates of brain and CNS cancers worldwide.

Methods: Data from successive volumes of Cancer Incidence in Five Continents were used, including 96 registries in 39 countries. We used Joinpoint regression to estimate the average annual percentage change and its 95% CI.

Results: Globally, a large variability in the magnitude of the diagnosis of new cases of brain and CNS cancer was found, with a 5-fold difference between the highest rates (mainly in Europe) and the lowest (mainly in Asia). Increasing rates of brain and CNS cancer were found in South America, namely in Ecuador, Brazil, and Colombia; in eastern Europe (Czech Republic and Russia), in southern Europe (Slovenia), and in the 3 Baltic countries. Trends were similar between sexes, although decreasing trends in men and women were seen in Japan and New Zealand.

Conclusions: Important regional variations in brain and CNS cancers exist, and given an increasing burden and risk worldwide, there is a need for further etiological research that focuses on the elucidation of environmental risk. The trends are sufficiently complex and diffuse, however, to warrant a cautious approach to interpretation.

Keywords: brain and CNS tumors; cancer registries; epidemiology; incidence; time trends.

Fig. 1

Truncated age-standardized incidence rates of brain and CNS cancers (per 100,000, ages ≥15 y, world standard), 2003–2007 by sex.

Fig. 2

Trends in truncated age-standardized incidence rates of brain and CNS cancers (per 100,000, ages ≥15 y, world standard) in selected populations in the Americas 1993–2007 by sex (black and gray lines: males and females, respectively).

Fig. 3

Trends in truncated age-standardized incidence rates of brain and CNS cancers (per 100,000, ages ≥15 y, world standard) in selected populations in northern and western Europe 1993–2007 by sex (black and gray lines: males and females, respectively).

Fig. 4

Trends in truncated age-standardized incidence rates of brain and CNS cancers (per 100,000, ages ≥15 y, world standard), 1993–2007 in in selected populations in southern and eastern Europe, Oceania, and Africa by sex (black and gray lines: males and females, respectively).

Fig. 5

Average annual percentage change (with 95% CIs) based on trends in truncated age-standardized incidence rates of brain and CNS cancers (per 100,000, ages ≥15 y, world standard), 1993–2007 by sex.