Brain tumour facts and figures
Children- brain tumours are the second most common cancer in children (under 15 years) accounting for approximately 18% of all new cases of childhood cancer (brain and CNS tumours account for approximately 25% of all childhood cancers).
Brain tumours in children tend to be medullablastomas. Adults- Malignant brain tumours are rare in adults with around 5,000 new cases a year diagnosed in the UK, accounting for approximately 2% of all new cancer cases (Other brain tumours may be confirmed as benign and some are undiagnosed due to their position preventing a biopsy).
Higher incidence in men, male to female ratio is 1.5:1. Adult brain tumours can occur at any age, the incidence rises from the age of 30 with the highest incidence being between 50 and 70 years of age. Most of these arise in the frontal, temporal and parietal lobes of the cerebrum, 86% are gliomas (includes astrocytomas, ependymomas, oligodendroblastomas and mixed gliomas).
Risk factors and causes are not well understood but radiation is recognised as a cause and radiotherapy for primary brain tumours is associated with a 55% increased risk of further brain tumours.
Risk factors include some genetic conditions such as neurofibromatosis, Li-Fraumeni syndrome and a family history of CNS tumours, diabetes in females, Parkinson’s disease and HIV infection or AIDS. (Secondary brain tumours have spread from tumours elsewhere in the body e.g. lung).
Brain tumour symptoms
- Nausea and vomiting.
Other symptoms may be related to the functions of the area of the brain where the tumour has developed.
Frontal lobe: changes in personality and intellect; uncoordinated walking or weakness of one side of the body; loss of smell; occasional speech difficulties.
Parietal lobe: difficulty speaking or understanding words; problems with writing, reading or doing simple calculations; difficulty coordinating certain movements, and finding your way around; numbness or weakness on one side of the body.
Temporal lobe: seizures, which may cause strange sensations: a feeling of fear or intense familiarity (déjà vu), strange smells or blackouts; speech difficulties; memory problems.
Occipital lobe: loss of vision to one eye, which the person may not notice at first and may sometimes be discovered during routine eye tests.
Cerebellum: lack of coordination; slurred speech (dysarthia); unsteadiness; flickering involuntary movement of the eyes (nystagmus); vomiting and neck stiffness.
Brain stem: unsteadiness and an uncoordinated walk; facial weakness, a one-sided smile or drooping eyelid; double vision; difficulty speaking and swallowing; vomiting or headache just after waking (this is rare). Symptoms may appear gradually. Meninges – headaches, sickness and problems with sight and movement.
Pituitary gland: the pituitary gland produces lots of different hormones so a tumour in the gland can cause a variety of symptoms including: irregular periods; infertility; weight gain; lethargy; high blood pressure; diabetes; mood swings; and enlarged hands and feet. A tumour in the pituitary gland can also cause pressure on the nerves to the eyes, causing tunnel vision.
Diagnosis of brain tumour
Investigations may include:
- Physical examination (will include neurological test, checking muscle strength, reflexes, sensation, eye tests and hearing tests)
- Blood tests.
- CT scan.
- MRI brain scan.
- PET/SPECT scan.
- Surgical biopsy (surgery may be to remove a sample of brain tissue to enable analysis followed by further surgery or in some cases the intention of the initial surgery may be to remove part or all of the tumour).
- Lumbar puncture.
Brain tumour treatment
Depends on several factors:
- The size and position of the tumour.
- The grade of the tumour.
- The stage of the cancer.
- Age and general health.
Surgery is usually the main treatment. In some cases of low grade gliomas, it may be adequate to monitor the patient after biopsy and perform surgery or give radiotherapy if later required but usually treatment needs to be as soon as possible as the tumours will spread and damage other parts of the brain.
In the majority of cases, surgical resection to remove part or all of the tumour will be performed. This will be a craniotomy that involves part of the skull bone being removed during the operation to enable the surgeon to access the tumour.
Benign tumours may also be resected as they can be life-threatening depending on their site in the brain, their ability to infiltrate locally and risk of becoming malignant.
Grade 1 and 2 tumours can be cured by complete resection or if incomplete resection further treatment with radiotherapy may be recommended. Grade 3 tumours will usually have debulking surgery followed by radiotherapy. Grade 4 astrocytomas tumours are very aggressive, also referred to as glioblastoma multiforme, these may have debulking surgery and radiotherapy and a chemotherapy drug called temozolomide.
Surgery may also be used to reduce pressure within the skull (called intracranial pressure) and to relieve symptoms (called palliative treatment) in cases when the tumor cannot be removed. Lymphomas of the brain are very rare; these are treated with radiotherapy and chemotherapy, not surgery.
Radiotherapy may be used as the main treatment or post-operatively. It may be used to treat patients where surgery is not possible due to the position of the tumour or patient’s general health.
Advances in radiotherapy have enabled very precise targeting of tumours, which is of great benefit in critical organs such as the brain. In some cases of brain tumours, IMRT may be suitable.
Intensity modulated radiotherapy (IMRT) has proved to increase the effectiveness of treatment by enabling the disease to be targeted very accurately hence reducing dose to surrounding healthy tissue and critical organs.
Image guided radiotherapy (IGRT) also enables the radiotherapy to be precisely delivered to the intended area which reduces potential radiation dose to healthy tissues and allows the radiography team to monitor any changes. It is important to achieve precise alignment for accuracy in delivering radiotherapy, therefore in most cases it is necessary for a ‘headshell’ to be produced.
This is achieved by using a specialised thermoplastic material which can be heated in warm water and then is laid over the patient’s face to form an accurately fitting customised shell which can then be used for the planning CT scan and for all the radiotherapy treatments.
It is a painless procedure which is clearly explained by the radiographers prior to the procedure. Some patients with small discrete tumours may benefit from stereotactic radiotherapy (SRT), which is highly accurate and involves directing small narrow beams of radiation to the tumour from different angles and requires the head to be held in a frame to ensure there is absolutely no movement during treatment, stereotactic radiotherapy is often recommended for tumours within or close to critical structures.
Image guided radiotherapy (IGRT) will also ensure precise delivery to the intended treatment area. Radiotherapy may also be used post-operatively (adjuvant) if complete excision of the tumour was not possible or if there is thought to be a risk of recurrence in grade 1 or 2 tumours and is usually prescribed for higher grades when surgery has been to debulk the disease only.
Radiotherapy is given sometimes in combination with chemotherapy if the disease recurs after treatment or after surgery for glioblastoma multiforme and is the treatment of choice in combination with chemotherapy for rare brain lymphomas.
Palliative radiotherapy may be given in advanced cases to help relieve symptoms such as severe headaches or visual disturbances due to raised intracranial pressure.
Post-operative chemotherapy may be used but is not standard; drugs used are usually procarbazine, lomustine and vincristine. It is sometimes given in combination with radiotherapy as described above.
Steroids are powerful anti-inflammatory drugs that are commonly prescribed to patients with brain tumours to help reduce the swelling in the brain and control symptoms. These may be prescribed pre or post-surgery, pre or post radiotherapy and in advanced cases.