Brain tumour is a term used loosely for any abnormal growth inside the skull. It may arise from brain itself, cranial nerves exiting the brain, coverings of brain(meninges), bony skull and bony skull base, or cancer may spread from any other organ in the body. The incidence of brain tumour means the number of new cases diagnosed per year for a given population and prevalence means the number of cases present in a given population at any point time. The incidence of primary brain tumours has been rising since the 1970s. This may be due to real increase in the incidence or may be due to better awareness and diagnosis as a result of advances in neuroimaging. The increase in incidence may also be a result of increase in average life span of human beings. As gliomas (most common malignant brain tumours) are more likely to occur in the elderly hence increased life span of humans leads to a larger population that is at risk of developing brain tumours.
The prevalence is also rising as the life span of newly diagnosed cases is increasing as a result of better medical care. For example, while the five-year survival for malignant brain tumour patients was approximately 25% in the 1990s, it has increased to approximately 35% recently. So, as the incidence and survival are rising; the prevalence of brain tumours is rising as a result.
Cause of Brain Tumor:
The cause of increasing incidence is not really known. Some studies have suggested that occupations like farming, firefighting, metal working, rubber and petrochemical industries may be associated with increased risk of developing brain tumours. Some have implicated diet (N-nitroso compounds in nitrate preserved food) as well as radiation from mobile phones and towers and from microwave ovens. However, there is no conclusive evidence. Only definite known factor causing brain tumours is ionizing radiation as from atomic bombs or radiation used in radiotherapy.Some rare familial inheritable cancer syndromes highlight the role of genes in the development of any cancer including brain tumours.
Therefore, while research is ongoing to tap the molecular mechanisms for prevention of brain tumours, humanity has to rely on better therapeutic methods in the form of microneurosurgery and chemoradiotherapy for relief from brain tumours.