What are primary malignant brain tumors?

Primary malignant brain tumors are cancerous growths that arise directly from brain or neural tissue and are not the result of spread of a tumor from outside the nervous system (metastatic brain tumors). They occur less frequently than tumors coming from outside and account for only about 2% of all cancers, but are the third most common cause of cancer deaths in the 15-34 age group. Unfortunately, these type of cancers tend to be associated with a high degree of morbidity and mortality. Although new treatments have not yet lead to a dramatic improvement in survival rates, there is still hope hope that advances in understanding of these tumors will lead to better success in the future.

Are there different types of primary malignant brain tumors?

Yes. Different types of primary malignant brain tumors arise from the different types of cells within the brain. Since most come from the supportive glial cells they are termed 'gliomas'. The gliomas can be further divided into tumors from different types of glial cells including astrocytomas (astrocytic cells), oligodendrogliomas (oligodendroglial cells), ependymomas (ependymal cells), and choroid plexus tumors. Of these, astrocytomas are by far the most frequent type. They are further categorized according to the aggressiveness of the individual tumors on a scale of 1 (least aggressive) to 4 (most aggressive). Grade 4 astrocytoma is also known as 'glioblastoma multiforme'.

What are the symptoms of a malignant primary brain tumor?

Unfortunately, high grade or aggressive tumors account for the majority of tumors at the time of discovery. Since they can occur in any part of the brain, the symptoms they cause vary according to the function of the underlying brain tissue they are invading or compressing. They may include weakness or numbness on one side, speech difficulties, personality change and cognitive problems. In addition there may be more non specific symptoms such as headache, nausea, vomiting, fatigue and seizures.

How are primary malignant brain tumors treated?

Like secondary brain tumors, primary brain tumors may be associated with significant swelling from leaky blood vessels (edema) which is usually treated first with a steroid (usually dexamethasone) along with a drug to protect the stomach from the steroid's side effects (e.g. ranitidine). If seizures are a problem standard anticonvulsants such as Phenytoin and Carbamazepine may be used. Depression can complicate treatment and is treated with antidepressants.

Further treatment with surgery, radiation and drug (chemo)therapy depends upon the type and aggressiveness of the tumor, which can usually be judged by CT or MRI scanning or biopsy.

Low grade (less aggressive) glioma treatment is controversial. Since these tumors may remain stable for long periods, some are simply watched carefully with serial scanning with or without biopsy.  Some physicians do advocate more aggressive treatment depending on the situation, including resection and chemotherapy. Chemotherapy is more useful for certain types of gliomas like oligodendrogliomas.

High grade (most aggressive) gliomas are often resected, however this almost never removes all of the tumor. This is usually followed by radiation, sometimes followed by chemotherapy.

Investigational therapies with new drugs that increase the effectiveness of traditional chemotherapy or attack the tumor cells in different ways offer hope for the future.