Brain Tumors: Primary - Common Brain Tumors

Common Brain Tumors: Ependymomas

GENERAL DESCRIPTION OF EPENDYMOMAS: Derived from cells that line the ventricles (fluid-filled brain cavities) and spinal cord central canal. Do not usually spread into normal brain tissue. Can block exits for cerebrospinal fluid and cause hydrocephalus. They constitute about 4% of all central nervous system tumors in adults and 10% of these tumors in children. About 30% of ependymomas develop in the spinal column.

Grade and Subtype

Descriptions of Subtypes

Usual Treatment

Low-grade (I).

Myxopapillary ependymoma (found in the spine).

Subependymoma (found in one of the ventricles).

No or very slow growth. In addition to grade, risk is also based on location of the tumor. Tumors on the spinal cord are more accessible than those in the fourth ventricle or in the middle of the lower back portion of the brain.

Can often be removed and cured with surgery, particularly those on spinal cord. Radiation may be needed. Chemotherapy (avoid radiation, if possible) in children under age 6).

Low-grade (II).

Papillary, cellular, and clear cell ependymomas.

Slow growth. Usually affect adults.

Surgery alone or followed by radiotherapy. For those who fail radiotherapy, possible use of nitrosourea-based chemotherapies or investigative drugs.

Grade III.

Anaplastic ependymomas.

Spreads to the spinal fluid.

Surgery followed by radiotherapy to brain and spinal cord. Possible shunt.

Grade IV.

Primitive neuroecto-dermal tumor (PNET). Composed of malignant forms of early, undeveloped nerve cells called neuroblasts. (This malignancy is also referred to as neuroblastoma.)

Very rare, but more common in children. Primitive nerve cells that grow very rapidly. Usually occur in cerebellum.

Surgery followed by radiotherapy to brain and spinal cord. Chemotherapy in young children. Investigative high-dose chemotherapy with stem cell rescue for children with relapsed cancer.

Common Brain Tumors: Oligodendrogliomas

DESCRIPTION OF OLIGODENDROGLIOMAS: They develop from oligodendrocyte glial cells. These cells form the protective coatings around nerve cells. Pure cell types are rare. Most often occur in mixed gliomas. Categorized as either low- or high-grade. Most are low grade II.

Description of Grade

Usual Treatment

Low Grade: Low grade difficult to tell from astrocytomas, although they are usually calcified. Very likely to bleed. Usually spread along nerve pathways of the brain and spine and rarely outside this area. In spite of difficulty in removing surgically, in some patients survival can be 30 - 40 years. Usually have better prognosis than astrocytomas of equal grade. Occur mostly in middle-aged adults, although there is also a small peak of incidence in children.

Treatment usually delayed until progression causes symptoms.

Surgery to remove whole tumor. Radiotherapy often follows in all adults over age 40 or in anyone in which tumor cannot be completely removed. Solid evidence is lacking on this approach, however, and there is some debate on its benefits.

Trials using chemotherapy after radiation are promising. Two-thirds of patients respond to PCV (combination of procarbazine, lomustine and vincristine.) Sustained remissions averaging 16 years often achieved. Pure oligodendrogliomas respond better than mixed gliomas. Temozolomide is showing promise as second-line treatment. Others under investigation.

Trials of additional chemotherapy for less well-differentiated tumors or for residual tumors after surgery.

High-grade. Anaplastic oligodendrogliomas.

Immediate treatment. Surgery to remove the whole tumor, if possible. Radiation typically follows surgery. Chemotherapy treatments either before or with radiation. Standard drugs are limited. Experts recommend trying investigative drugs. Temozolomide and retinoic acid may be useful. Possible additional drugs include melphalan, thiotepa, carboplatin, cisplatin, and etoposide.

(Numerous biologic markers may help identify specific oligodendrogliomas that will respond better or worse to specific treatments.)