Epidemiology
There are between 5-15 primary brain tumours per 100,000 population. This accounts for 5-10% of all cancers in all age groups and probably 30-40% of tumours in children. Tumours may also spread to the brain from distant sites (secondary tumour). The commonest tumours which spread to the brain are lung (44%), breast (10%), kidney (7%), bowel (6%), melanoma (3%) and 10% are from an unknown source. Brain tumours themselves almost never spread out from the central nervous system.
Presentation
Tumours usually present in one of three ways: headaches (54%), progressive neurological deficit (68%) or seizures (26%).
The headaches are related to raised pressure inside the brain. The classical description is one of early morning headaches, often over the forehead, which is present when the person wakes up. The headache usually settles by afternoon. Many patients also complain of nausea or vomiting.
Any neurological deficit will depend on the site of the tumour. The commonest deficit seen is a weakness (frontal tumour), some patients may have numbness (parietal tumour), problems with speech (dominant temporal tumours), visual problems (temporal, parietal or occipital tumour) or a change in personality (frontal tumour). Certain tumours present in a very specific fashion, i.e. endocrine problems with a pituitary tumour.
