Astrocytomas or Gliomas
These tumors occur and infiltrate or invade the brain tissue itself. This infiltration can make them difficult to treat. Even with radical surgery, tumor cells may be left behind - like the "roots" of a tree. Like all gliomas, astrocytomas can be located either superficially (easier to remove) or deep within the brain (difficult to remove) and can affect critical structures.
When a patient is diagnosed with an astrocytoma, there are several key factors of the tumor that affect the prognosis: its location, size, and grade. These tumors can be either superficial or deep. In addition, some may affect so-called eloquent areas of the brain, such as language or motor function.
At the time of diagnosis the CT or MRI scans are useful to determine the location and size of the tumor. Both of these factors will impact the type of surgery planned, as well as how much and how safely the tumor can be removed. Certain tumor locations only can be biopsied with a needle. For example, gliomas in the brain stem near the cord often are low grade. They are dangerous because they occur in a critical highway where information travels between all areas of the brain and spinal cord.
The tumor grade is based on the tumor's histologic appearance, or how it looks under the microscope to the pathologist. Astrocytomas are graded on a scale from very benign (grade 1) to very malignant (grade 4).
Low-grade astrocytomas: (Grades I or II) are benign and occur generally in children or young adults. These tumors have a better prognosis than higher grade astrocytomas. Although management of these low-grade astrocytomas is controversial, those tumors are treated initially by surgery to remove as much as possible. One of the concerns in adults is that they can become more malignant and change into a higher-grade or malignant tumor. The benefits of radiation therapy, as well as chemotherapy, in adults are still under investigation.
Higher grade anaplastic astrocytomas: (Grade III/IV) are more aggressive tumors and treated more radically. Biopsy performed using a stereotactic needle or at the time of open surgery is required for diagnosis. A gross total resection should be performed whenever possible. Even in such cases, additional therapy, such as radiation therapy and chemotherapy, is necessary to help delay a recurrence.
There are several treatment options:
Surgery for removal is generally advised for patients with limited cancer elsewhere in the body and a single brain metastasis. One advantage for the surgeon and patient in the operative removal of a metastasis is that there is usually a good separation between the tumor and surrounding normal brain tissue. This minimizes the amount of manipulation needed to resect the tumor. Also metastatic tumors tend to be superficial and near the brain surface. Computer-assisted surgery, often using a frameless stereotactic system or robotic microscope, has been a major advance in the resection of brain tumors.
Radiation therapy to the brain is almost always advised for patients with metastatic brain tumors. These treatments are performed on an outpatient basis. Even patients who had a single metastasis surgically removed should have radiation therapy. Stereotactic radiosurgery is a newer type of focused radiation that has been used with some success for patients with metastatic brain tumors.