Definition & Overview
Astrocytes belong to a group of cells called glial cells that form the brain’s supportive tissue. The others are called oligodendrocytes and ependymal cells. When a tumour develops in the astrocytes, it’s referred to as an astrocytoma.
Astrocytomas are either infiltrating or non-infiltrating. Infiltrating types are those that have a rapid growth rate and spread to nearby brain tissue. Non-infiltrating types are contained within the cell and take a longer time to grow.
Astrocytomas are further classified into grades, depending on how fast they grow. A grade I astrocytoma is a non-infiltrating type called pilocytic astrocytoma or a juvenile pilocytic astrocytoma (JPA). This type of astrocytoma usually occurs in the cerebellum, optic nerve pathway, brainstem, or cerebrum. JPAs grow slowly but they have a tendency to grow into a large tumour.
A Grade II astrocytoma is infiltrating, but they have a slow growth rate. However, it does have a tendency to spread to other parts of the brain. This type of astrocytoma is more prevalent in adults between the ages 20 and 40.
A Grade III astrocytoma is infiltrating and it has a faster growth rate than those with a Grade II classification. It is also called anaplastic astrocytoma and accounts for 4% of brain tumours.
A Grade IV astrocytoma, also referred to as a glioblastoma or GBM, is the most aggressive. This type is more common in men between ages 50 to 60. 23% of astrocytomas are Grade IV.
Cause of Condition
The exact cause of an astrocytoma is unknown. Scientists believe that genetic factors, radiation, and toxins in the environment contribute to the formation of the tumour.
Astrocytomas produce a wide variety of symptoms because they affect the central nervous system. The most common are headaches, seizures, sensory anomalies, cognitive impairment, nausea, vomiting, an altered mental status, vision problems, and a condition called ataxia, which is essentially a lack of muscle coordination.
Patients also display a loss of balance while walking, an excessive amount of energy or no energy at all, unexplained weight changes, changes in behavior and personality, and handwriting or speech difficulties.
Who to See & Types of Treatment Available
If you notice any of the above symptoms, you should consult your family doctor. Those symptoms are similar to other diseases, but if the doctor suspects that there is a problem with the nervous system, you will be referred to a specialist, such as a neurologist, neuropathologist, a psychologist, or a neurosurgeon.
Although your doctor will likely have you undergo a variety of laboratory tests to determine the cause of the symptoms, it’s important to understand that no lab test can provide an indication of the presence of an astrocytoma. Astrocytomas can be identified through an MRI or CT-scan. MRIs are the primary choice of doctors, but when the use of an MRI may affect a patient’s condition, a CT-scan is performed instead.
You may undergo other types of brain scans, such as a Magnetic Resonance Spectroscopy (MRS), or Magnetoencephalography (MEG). You may also undergo an angiography to rule out vascular causes or to determine the amount of blood being supplied to the tumour. Radionuclide scans, such as a Positron Emission Tomography (PET), a Single Photon Emission Computerized Tomography (SPECT), or titanium based imaging are performed to evaluate the tumour. Other types of diagnostic procedures include EEG, ECG, and a CSF study.
Once the condition has been confirmed, a treatment plan will be immediately formulated. Being diagnosed with this condition will likely be a shock. You may and should seek a second opinion.
There is no standard treatment for astrocytoma. The specialists handling your case will discuss the various aspects of your condition and decide on a particular treatment option. A health team consisting of neuro-oncologists, neurologists, radiation oncologists, neuropathologists, neuropsychologists, and neuro-radiologists will likely manage your condition. All of them will have their own inputs on how your condition should be treated.
The treatment will depend on the size, location, and type of astrocytoma. Your health will also be evaluated. Treatment options include surgery, radiotherapy, chemotherapy, adjuvant temozolomide, concomitant temozolomide, and adjuvant carmustine. In most cases, surgery is the preferred treatment method. However, studies have shown that there is no benefit of performing surgery on astrocytomas that have already affected the brain stem.
Surgery is usually performed to remove the astrocytoma and/or diagnose the condition further. If the astrocytoma cannot be removed, other forms of treatment will be applied. In cases where the doctor sees a possibility that the signs and symptoms will go away on their own, no treatment will be provided. Instead, the condition will be closely monitored.
If surgery is not the primary option, the doctors may opt for radiation therapy, chemotherapy, high-dose chemotherapy with stem cell transplant, or targeted therapy. Currently, various clinical trials are being performed to assess other treatment methods. A patient may opt to participate in such trials. This decision can be made before or during any type of treatment method.
There is also a possibility of fluid build up around the brain and spinal cord. In these cases, the attending doctor will elect to perform a cerebrospinal fluid diversion procedure to remove fluid and relieve pressure.
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