User:DerekvG/sandbox/braintumor/lowgrade astrocytoma

Lowgrade Astrocytoma also Fibrillary (or diffuse) Astrocytomas are a group of primary slowgrowing neoplasms of the brain, that typically occur in adults (between 20 and 50), on MRI images the tumor is vaguely outlined which is why some authors also use the name Diffuse Astrocytoma , often pathological examination is required to confirm the diagnosis. The tumor forms from neoplastic transformation of the Astrocytecells of the brain. They may be located anywhere in the brain, but most commonly found in the cerebral hemispheres. As the name "diffuse astrocytoma" implies, the outline is not clearly visibke because the borders of the neoplasm tend to grow tiny microscopic tentacles that spread into the surrounding brain tissue. Those tentacles intermingle with brain cells that are performing their normal functions and cannot always be seen during surgery, thus impeding complete tumor ressection.

In an article published on Emedcine^[1] George I Jallo, MD,^[2] describes lowgrade astrocytoma : "Low-grade astrocytomas are a heterogeneous group of intrinsic central nervous system (CNS) neoplasms that share certain similarities in their clinical presentation, radiologic appearance, prognosis, and treatment. The most common intrinsic brain tumor, glioblastoma multiforme, is high grade and malignant. This contrasts with low-grade astrocytomas, which are less common and therefore less familiar to practitioners. The strategies for diagnosis and treatment are also more controversial. Improvements in neuroimaging permit the diagnosis of many low-grade astrocytomas that would not have been recognized previously. Low-grade astrocytomas are, by definition, slow growing, and patients survive much longer than those with high-grade gliomas. Proper management involves recognition, treatment of symptoms (eg, seizures), and surgery, with or without adjunctive therapy. Low-grade astrocytomas are found in both the brain and the spinal cord."

Symptoms

Seizures, frequent mood changes and headaches are among the earliest simptoms of the tumor, hemiparesis is common.

Occurence

Diagnosis

Usually - depending on the interview of the patient and after a clinical exam which includes a neurological exam, an EEG can help for children experiencing seizures (through a continuous EEG recording of the brain's electrical activity in order to identify and localize seizure activity). A CT scan and or MRI scan of the brain may show the presence of a mass which doesn't light up when a contrast dye is given. Once a scan shows mass suspected of being a low-grade astrocytoma, the next step is a consultation with a neurosurgeon. The neurosurgeon may recommend a biopsy to help to confirm the diagnosis or surgery to remove the tumor.

Visual aspect

On CT scan or MRI images a diffuse actrocytoma looks like a diffuse outlined mass which doesn't light up when a contrast dye is given.

Treatment

Treatment options include surgery, radiation, radiosurgery and chemotherapy.

The main goal of surgery is to remove as much of the tumor as possible without injuring brain tissue needed for neurological function (such as the ability to speak, walk, motor skills, etc.). The infiltrating growth of microscopic tentacles might make complete tumor removal difficult to impossible. If the tumor cannot be completely removed, surgery can still reduce or control tumor size.

The extent an planning of surgery depends on

medical history and overall health condition
type, location, and size of the neoplasm
age and tolerance for specific medications, procedures or therapy
expected progress of the neoplasm

The goal of radiation therapy is to selectively kill tumor cells, while leaving the normal brain tissue unharmed. Radiation therapy consists of multiple treatmentsessions of pre-calculated doses of radiation applied to the area of the tumor. Each dose causes intracellular damage to healthy and normal cells indiscriminately. By the time the next treatment is applied, most of the normal cells have repaired the damage, but the tumorcells haven't. This process is repeated for a total of 10 to 30 treatments, depending on the type of tumor. Sometimes this treatment is performed after ressection provides some patients with improved outcomes and longer survival rates.

Radiosurgery is a treatment method that focusses minimal radiation doses (through computerized modelling) at the exact location of the tumor (or the rim of the former - ressected - neoplasm and while minimizes the radiation dose to the surrounding healthy (brain)tissue. Radiosurgery may be a complementary treatment after surgery, or it may represent the primary treatment technique.

Patients undergoing chemotherapy are given special (highly toxic) drugs designed to kill the tumor cells, and has strong side-effects. Although chemotherapy may improve overall survival (in patients with the most malignant primary brain tumors) it's effective only for about 20 percent of patients.

Presently researcher are investigating a number of promising new treatment tehniques including gene therapy, highly focused radiation therapy, immunotherapy and novel chemotherapies.

Side effects

Persons suspected of or diagnosed with with diffuse astrocytomas may experience side effects related to the tumor itself and related to the treatment.

Effects like seizures might progressively improve as recovery progresses, but will be medicated from the symptom onset and even while definitive diagnosis is still underway .
Symptoms related to increased pressure in the brain often disappear after surgical removal of the tumor.
Steroid-treatment is often used to control tissue swelling that may occur pre- and post-operatively.

Side effects of treatment

epileptic seizures

People may experience seizures as a symptom of their desease, but any person undergoing brain surgery is at risk from epileptic seizures.

Medication is administered to minimize and eliminate (completely) the occurence of seizures.

Parents of children after surgery should be made aware of this fact and should be prepared to take adequate action in case of the seizure (see brain tumor)

radiation therapy

Radiation therapy may cause swelling related to tissue inflammation.

This inflammation may lead to symptoms like headaches and may be treated with oral medication.

chemotherapy

Chemotherapy often has side-effects due to the toxicity of the medication, and is treated symptomatically.

expected outcome after treatment

Lowgraded (Fibrillic/Diffuse) Astrocytomas are associated with a fairly high rate of cure, after complete ressection. Incomplete ressection most commonly is the cause for the tumor to recur, requiring more surgery or other complmentary treatments.

how to respond to progressive or recurrent disease?

The recommended course of action according to different literature sources is to monitor and reattempt either complete surgical removal or any combination of the therapies discussed before.

Mortality

References

^ http://emedicine.medscape.com
^ George I Jallo, MD, Associate Professor of Neurosurgery, Pediatrics and Oncology, Director, Clinical Pediatric Neurosurgery, Department of Neurosurgery, Johns Hopkins University School of Medicine,

Additional images

External links

PLGA Pediatric Lowgrade Astrocytoma's
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[2]
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Category:Diseases and disorders Category:Brain Category:Oncology Category:Disorders causing seizures Category:Nervous system neoplasms

[Emedcine-1] ttp://emedicine.medscape.com

[gallo-2] George I Jallo, MD, Associate Professor of Neurosurgery, Pediatrics and Oncology, Director, Clinical Pediatric Neurosurgery, Department of Neurosurgery, Johns Hopkins University School of Medicine,

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