Primary cancer of the brain is rare. This page contains brain cancer incidence statistics with information by age, and trends over time.The ICD code for brain and other central nervous system cancers is ICD9 191-192 and ICD10 C70-72.
In 2005 there were 4,555 new cases of brain or central nervous system cancers diagnosed, around 7 per 100,000 population. A GP will see, on average, four new patients with primary brain tumours during their career. Although brain tumours account for less than 2% of all primary tumours they are responsible for 7% of the years of life lost from cancer before age 70.
Table 1.1 shows the number of new cases and incidence rates for brain and central nervous system cancers by sex for the UK and its constituent countries.
Brain tumours occur at any age and represent the commonest site for solid tumours in childhood. A small peak in incidence of brain tumours in early childhood drops to a poorly defined minimum in teenage years rising to a second major peak in people in their 70's as Figure 1.1 shows. The decline after age 75 may be an artefact of data collection. The tumour type and site vary with age with clear distinctions between adult and childhood brain tumours. Most childhood brain tumours (70 – 80%) arise infratentorially (glial tumours, medulloblastoma) or in the midline (germ cell tumours, craniopharyngioma). Glial tumours in children are more frequently low grade c. In adults most brain tumours are supratentorial where high grade gliomas and meningiomas predominate.
Interpretation of brain and central nervous system cancer incidence trends over time is difficult for several reasons including changes in coding practices and coding classifications, and the introduction of new more accurate diagnostic techniques. In Great Britain the age-standardised incidence rates for brain and central nervous system cancers have increased slightly between 1975 and 2005 as shown in Figure 1.2 but much of this increase is confined to the over-65s.
What proportion of the increase is artefactual rather than real is uncertain and it has been suggested that the introduction of computed tomography scanning in the 1970s and magnetic resonance imaging in the 1980s is likely to account for a substantial proportion of the increase, particularly at older ages. Some specific types of brain tumours are said to be increasing in incidence for example, gliomas in the elderly and lymphomas in both immune competent and incompetent patients.
UK brain and central nervous system tumours incidence trends are shown in Figure 1.3.