Brain tumour

brain tumour

A brain tumour occurs when abnormal cells form within the brain. There are two main types of tumours: malignant tumours and benign (non-cancerous) tumours. These can be further classified as primary tumours, which start within the brain, and secondary tumours, which most commonly have spread from tumours located outside the brain, known as brain metastasis tumours. All types of brain tumours may produce symptoms that vary depending on the size of the tumour and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.

The cause of most brain tumours is unknown. Uncommon risk factors include exposure to vinyl chloride, Epstein–Barr virus, ionizing radiation, and inherited syndromes such as neurofibromatosis, tuberous sclerosis, and von Hippel-Lindau Disease. Studies on mobile phone exposure have not shown a clear risk. The most common types of primary tumours in adults are meningiomas (usually benign) and astrocytomas such as glioblastomas. In children, the most common type is a malignant medulloblastoma. Diagnosis is usually by medical examination along with computed tomography (CT) or magnetic resonance imaging (MRI). The result is then often confirmed by a biopsy. Based on the findings, the tumours are divided into different grades of severity.

Treatment may include some combination of surgery, radiation therapy and chemotherapy. If seizures occur, anticonvulsant medication may be needed. Dexamethasone and furosemide are medications that may be used to decrease swelling around the tumour. Some tumours grow gradually, requiring only monitoring and possibly needing no further intervention. Treatments that use a person’s immune system are being studied. Outcomes for malignant tumours vary considerably depending on the type of tumour and how far it has spread at diagnosis. Although benign tumours only grow in one area, they may still be life-threatening depending on their size and location. Malignant Glioblastomas usually have very poor outcomes, while benign meningiomas usually have good outcomes. The average five-year survival rate for all (malignant) brain cancers in the United States is 33%.

Secondary, or metastatic, brain tumours are about four times as common as primary brain tumours, with about half of metastases coming from lung cancer. Primary brain tumours occur in around 250,000 people a year globally, and make up less than 2% of cancers. In children younger than 15, brain tumours are second only to acute lymphoblastic leukemia as the most common form of cancer. In Australia, the average lifetime economic cost of a case of brain cancer is $1.9 million, the greatest of any type of cancer.