An astrocytoma is the most common type of primary brain cancer. There are several types based on cell function and severity. There are roughly 12,000 new cases found every year in the United States. These can be very aggressive cancers.
Astrocytomas arise from a special type of cell in the white matter of the brain. This cell is called an astrocyte and is star-shaped. Astrocytes have a supportive role to the neurons, or nerve cells, in the brain. They help with the nutrition, protection, and functioning of the nerve cells. In astrocytomas, these cells grow without any regulation and form a mass. If the cells grow uncontrollably and rapidly it is termed malignant. If these cells are not doing their job, then the neurons in the brain are neglected. The growing mass of cells pushes on the brain creating an increase in pressure. These cells also take all the nutrients that the working cells need to function. Thus, the neurons in the brain are damaged when astrocytomas occur.
Astrocytomas are graded or grouped according to their severity. There are low grade astrocytomas that occur in children and young adults. Then there are malignant astrocytomas such as “anaplastic astrocytoma” and “glioblastoma.” These typically occur in adults in their forties and fifties. These can grow fast and have multiple tumors. Glioblastomas are the most malignant. The low grade astrocytomas can progress to one of these malignant tumors. When this happens it is known as a “secondary” brain tumor. Any of the tumor types can develop without any previous problems.
Low grade astrocytomas usually present with seizures first. Any of these brain cancers can increase the pressure on the brain, with symptoms of headache, nausea, and vomiting. Patients can also have changes in consciousness, personality changes, and neurologic deficits, all based on the location of the tumor within the brain. Neurologic deficits are things like weakness or paralysis in the arms or legs, tremors, decreased sensation, difficulty speaking, slurred speech, confusion, drowsiness, memory loss, trouble hearing, or trouble with vision.
If a brain tumor is suspected, a brain scan is done: either a CT or MRI. And a special scan called a PET scan may also be done. A diagnosis may require surgical brain biopsy. A brain biopsy is where the neurosurgeon makes a small hole in the skull and takes a sample of the tumor for testing.
Based on the specific diagnosis and severity, one of the following or a combination of the following may be used to treat the tumor: surgical resection, radiation, or chemotherapy. Surgical resection involves a craniotomy and removal of as much tumor as possible. In a craniotomy a large hole is made in the skull and the tumor is accessed. A complete removal is ideal, but sometimes, based on the location and size, this is not feasible or safe. If the tumor is very aggressive, a debulking of the tumor may help with symptoms. This is where they perform a craniotomy and remove portions of the tumor to alleviate pain and symptoms.
Surgery may be followed by treatment with radiation and/or chemotherapy. Radiation and chemotherapy can be used to stop the tumor from growing any further. Radiation attempts to kill or stunt the cancer cells with high energy. Chemotherapy also attempts to kill/stunt the cancer cells with chemicals. Radiosurgery may be used, where a very high energy beam of radiation is directed specifically on the tumor to kill the cancer cells.
The treatment outcome depends on the patient's age, cell type, severity of symptoms, and location of the tumor. Again, this cancer has the potential to be very aggressive. Surgery, radiation, and chemotherapy can be used to cure or to make the brain cancer as tolerable as possible. Survival rates vary by type of tumor. Your doctor will discuss the best options and the specific type of tumor with the patient.
Lindsey Parker PA-C; Justin Fraser M.D.