Brain Cancer (Gliomas)
Diagnostics Tests For Brain Cancer/ Gliomas
Clinical history and examination: A clinician will ask for symptoms such as headache, nausea or vomiting, confusion, a decline in brain function, loss of memory, personality changes, problems with vision, speech difficulties and seizures. During a neurological exam, a doctor examines the patient’s vision, hearing, balance and reflexes.
Radiological tests: Magnetic resonance imaging (MRI) - It is often used to help diagnose brain tumours and sometimes uses a dye injected through a vein to better analyse the tumour. There are a number of specialized MRI scans such as functional MRI, perfusion MRI and magnetic resonance spectroscopy that may be performed as well. CT scan- This radiological test is often the first test performed when a brain tumour is suspected. Positron emission tomography (PET) - It is used to test for the spread of cancer to other parts of the body.
Biopsy: A sample of tissue is collected to be analysed in the laboratory. Depending on the location of the tumour, the sample may be acquired using a fine needle or as part of an operation to remove the tumour. For tumours that are hard to reach or in sensitive areas of the brain, a stereotactic needle biopsy may be done by drilling a small hole through the skull under CT or MRI guidance, and a thin needle is then inserted to remove the sample. The pathologist examines the physical appearance and growth rate of the tumour and tumour cells.
Molecular markers: Cancer comes about due to genetic mutations. There are various genetic and chemical molecules that can help the clinical team choose the right path to treat the glioma, which are known as molecular markers. These may include genetic loss on chromosomes or mutations of specific genes. These markers can help predict the rate of growth and spread of the disease as well as are targets for targeted treatments and are collected and assayed using fluids like blood, serum or the cerebrospinal fluid that surrounds the brain and spinal cord. These are conducted by pathologists or by genetic experts.
Treatment Of Brain Cancer (GLIOMAS)
The management of cancer depends on various factors, including the stage of the cancer, additional health issues, age etc. An onco surgeon may advise surgery, radiation or chemotherapy.
- Surgery: Some of the best cancer doctors in India have said that surgical removal has better survival rates. However, in patients in whom radical surgery is expected to lead to loss of neurological function, it is aimed just at removing as much tumour as is safely possible. The tissue removed is usually sent for histopathological and molecular analysis of the tumour. Side effects: Seizures, bleeding, neurological deficits (removal of normal brain tissue leading to side effects), infections, leakage of cerebrospinal fluid (specialised fluid around the brain and spinal cord).
- Stereotactic and open biopsy: It is performed in patients in whom surgery is not safe due to the tumour location. It may be in an inaccessible region or a region that carries a high-risk damage to critical nervous tissue. A stereotactic biopsy using a CT or MRI is a less invasive way to obtain the tumour sample and an open biopsy is a form of surgery that uses local or general anaesthesia to remove the tissue required for laboratory diagnosis of cancer.
- Radiotherapy: Radiation uses high-energy beams to kill tumour cells and is administered from a machine outside the body (or external beam radiation). Post-operative radiotherapy is a standard of care for low-grade gliomas and is administered over a number of sessions extending over a couple of weeks. Post-operative radiotherapy is especially considered in the presence of factors which suggest a higher likelihood of tumour recurrence such as tumours larger than 5 cm, patient age over 40 years, depending on the extent and tumour cell characteristic etc. This is also known as Whole brain radiotherapy and affects both the tumour cells and normal nerve cells. Stereotactic radiation therapy is a minimally invasive approach to the treatment of brain tumours. This form of therapy uses thin beams of radiation to destroy only the tumour cells. It requires specialised imaging techniques and computerized planning to precisely focus a high dose of radiation on the brain tumour, while sparing normal tissue. It is associated with lesser side effects than ‘whole brain radiotherapy’. Side effects: Common side effects include fatigue, headaches, scalp irritation, seizures, nausea, and drowsiness.
- Chemotherapy: Chemotherapy uses drugs to kill tumour cells that may be taken orally or injected into a vein. It is commonly used in combination with radiation therapy to treat gliomas. Side effects: The side effects depend on the type and dose of drugs received. Common side effects include nausea and vomiting, headache, hair loss, fever, and weakness. Some side effects may be managed with medication.
- Targeted drug therapy: Targeted drug treatments block specific pathways in cancer cells leading to their death. Targeted drug therapy stops the formation of new blood vessels, cutting off blood supply to a tumour and leading to the death of the tumour cells. The medical oncologist will advise the patient regarding the best agent depending on specific patient and tumour characteristics.
Alternating Electric Field Therapy: This therapy is sometimes used for brain and spinal cord tumours. Research has suggested that exposing some types of tumour cells to alternating electric fields can interfere with the cells’ ability to grow and spread. These fields are created by a portable device. Side effects: Side effects of the device tend to be minor, and can include skin irritation at the electrode sites, trouble sleeping, mood changes, and a slightly increased risk of headaches and seizures.
Sources: Mayo Clinic; European Society of Medical Oncology (ESMO); Texas Oncology; American Cancer Society