May 20, 2008

Senator Kennedy's glioma

Ted Kennedy has been diagnosed with a malignant brain tumor called a glioma.

What's a glioma?

Gliomas comprise a heterogeneous group of neoplasms that differ in location within the CNS, in age and sex distribution, in growth potential, in extent of invasiveness, in morphological features, in tendency for progression, and in response to treatments.

Glioblastoma multiforme (GBM) is by far the most common and most malignant of the glial tumors. Composed of a heterogenous mixture of poorly differentiated neoplastic astrocytes, glioblastomas primarily affect adults, and they are located preferentially in the cerebral hemispheres.

How is it treated?

One type of treatment is external beam radiation, in which radiation passes through the brain to the tumor. Unfortunately, this exposes healthy brain tissue to potentially damaging radiation. Another treatment is surgical removal of the tumor, if possible, followed by chemotherapy. All of these treatments are difficult to go through, and pose risks to the patient. Unfortunately, many gliomas grow back even after treatment.

There are several reasons why it is hard to get rid of these types of brain tumors. Some drugs can't get into the brain because of a special filtering mechanism in the body (called the blood-brain barrier). Some tumors spread into (infiltrate) the tissues around them with tiny projections. Many tumors have more than one kind of cell in them, so chemotherapy directed at one kind of cell in the tumor will not kill the other cells.

What's a typical prognosis? Depends on the type. The doctors haven't been specific, but it appears that astrocytoma is the most likely, from the descriptions we have been given.

Gliomas can be astrocytomas, ependymomas or oligodendrogliomas. The different types have very different outlooks.

Astrocytomas can be slow growing (grade 1), moderately fast growing (grade 2), anaplastic astrocytoma (grade 3 ) or very fast growing (glioblastoma multiforme, GBM also called grade 4 astrocytoma).

The prognosis for glioma depends on

* The grade
* Where in the brain the glioma is
* Whether the tumour can be removed surgically
* Age
* Whether it responds to radiotherapy or chemotherapy

Few astrocytomas can be completely removed. So, unfortunately adults with a low grade astrocytoma don't always do as well as you might expect. Rates from clinical studies show that between 27 and 85 out of every 100 people diagnosed live for at least 5 years. This seems like a very broad range. It depends on many factors, including where the tumour is and how it responds to treatment. Low grade tumours in adults also tend to change into high grade tumours after some time.

For grade 3 astrocytomas, (anaplastic astrocytoma), about half the adults diagnosed (50%) live for at least 3 years. For the most aggressive grade 4 astrocytomas (glioblastoma multiforme) around 1 in 5 people (20%) live for more than 2 years.

More at the links.

Posted by Linkmeister at May 20, 2008 09:51 AM | TrackBack