Using MRS chemical composition of the tumor and the metabolite intensities can also be ascertained along with the morphological characterisitcs. Thus MRI provides better information which is useful in grading the tumor. For grade 4 astrocytoma's spectroscopic studies reveal high Cho, high lipid, high lactate and low NAA values. However, the MRI testing is time consuming (40 to 90 minutes) and is problematic for claustrophobic patients. [eMedicine] Biopsy of the affected brain tissue will also help in determining the nature of the abnormal tissue growth. Treatment

Treatment for astrocytoma includes, surgery, chemotherapy, radiation and gluco corticoid medication. Treatment improves the survival rates for patients and the type of treatment depends on the growth and location of the tumor. First grade tumors such as Pilocytic Astrocytomas are easily treated by resection. In most cases removal of the affected part would be sufficient. However, if the location of the tumor makes surgery an impossible choice then the condition is treated by chemotherapy and radiotherapy. In fibrillary, anaplastic astrocytoma and Glioblastoma complete removal by surgery is followed by chemotherapy and radiation. Total cure is possible for Pilocytic Astrocytomas after surgery while the prognosis for fibrillary astrocytoma depends on whether or not the tumor cells are transformed into more malignant types. Also recurrence is high in fibrillary astrocytoma.

With the advancements in medical technology such as intraoperative neuronavigation that allows the surgeon to see the surgical region on the computer screen, and the use of high power microscopes to magnify the surgical zone, it is possible to limit damage to adjacent healthy tissues while doing a tumor resection. Radiation therapy may be both external and internal. In the later case, radioactive materials are implanted near the tumor zones. It is now common to use biodegradable BCNU polymer wafer implants for radiation therapy. Also, the use of scalpel for tissue extraction can be eliminated by using the 'ultrasonic aspiration' method. Ultrasonic waves are focused on the tumor area to break it down and the fragments are removed by suction. [IRSA]

Radiosurgery

Stereotactic radiosurgery is a non-invasive form of therapy, which can be done in a session by a neurosurgeon. The aim of the therapy is to destroy the tumor cells by concentrating a series of cobalt 60 beams from different angles onto a spot. Since individual beams are not strong enough to destroy healthy cells the therapy does not affect healthy cells that is passes thorough but only affects the area on the brain where all the beams converge (the tumor zone). However, this therapy has its limitations and only an area of 4 cm can be treated at any one time so it might involve multiple sessions. Radiosurgery is typically recommended for patients who do not have the need for surgical intervention. However, this therapy is also used post surgery to remove traces of tumor cells that might still exist. Though the radiation does not destroy healthy cells, multiple sessions of radiotherapy are not recommended for children in view of the possible long-term damage to a brain which is still in the developmental stage. [IRSA]

Chemotherapy

Chemotherapy is a much older form of treatment and involves a combination of drugs to destroy the cancerous cells. The usefulness of drugs in the treatment of tumors is largely affected by the 'blood brain barrier' that filters of most toxic substances from entering the brain. Chemotherapy is usually given as a secondary therapy after surgery and alongside radiotherapy. Chemotherapy requires that the patient be healthy enough for the treatment. [IRSA] Drugs can be given orally...

Glucocorticoids are one of the main pharmacological interventions in providing symptomatic relief for patients affected by brain tumor. The edema that results from brain tumor increases the intra-cranial pressure and gives severe forms of headache. Glococorticoids and other cortisone drugs help in alleviating the symptoms by reducing the water level in the 'peritumoral zone' of the edema. [Sosuke Minamikawa et.al, 2004]
Conclusion

Glial tumors are the most common and dangerous forms of brain tumors. Treatment by a combination of methods may improve the prognosis and the quality of life for the patient. While in some tumors such as the Pilocytic Astrocytomas and Fibrillary Astrocytomas, total recovery maybe possible we are still a long way from providing complete relief for all the different types of astrocytomas. Treatments for astrocytoma may also result in serious side effects as it involves the brain. Advancements in the diagnostic methods such as MRS, ultrasonic aspiration and in surgical procedures such as intraoperative neuronavigation, Gamma Knife radiosurgery, etc. have improved the precision for the surgeon and outcome for the patient to a significant extent. However, significant advancements in molecular biology could only yield us the victory over the battle with tumor. It is hoped that with the huge volume of research that is currently underway in understanding the pathology of the disease it would not be long before successful treatment and prevention methods could be developed for astrocytoma and all other forms of brain tumors.

Bibliography

Capodano AM. Nervous system: Astrocytic tumors. Atlas Genet Cytogenet Oncol Haematol. November 2000. Available at, http://AtlasGeneticsOncology.org/Tumors/AstrocytID5007.html

BTS, "Brain Tumor Facts & Statistics," Accessed Nov 18th 2007, available at http://www.tbts.org/itemDetail.asp?categoryID=384&itemID=16535

Karen T. Barker and Richard S. Houlston, "Overgrowth syndromes: Is dysfunctional P. 13 Kinase signalling a Unifying mechanism," European Journal of Human Genetics (2003) 11, 665-670. Available online at, http://www.nature.com/ejhg/journal/v11/n9/full/5201026a.html

Medscape, " a Review of Astrocytoma Models: Molecular pathologies of Astrocytoma," Neurosurgical Focus 8(4), 2000 eMedicine, "Astrocytoma, Brain," Accessed on Noiv 18th 2007, available at http://www.emedicine.com/radio/topic60.htm

Nobuaki Ishii and N. de Tribolet, "Are p53 mutations and p53 over expression prognostic factors for astrocytic tumors? Critical reviews in Neurosurgery, vol 8 / no 5, Sept 1998.

Pamela a. Silver PhD, "RNA Binding Proteins in the Progression of Adult Astrocytic Tumors," Accessed Nov 18th 2007, Available online at, http://www.goldhirshfoundation.org/project_summaries_2002.htm

NCI, "Adult Brain Tumors: Classification," Accesed Nov 18th 2007, available at http://www.cancer.gov/cancertopics/pdq/treatment/adultbrain/HealthProfessional/285.cdr#Section_285

Sosuke Minamikawa et.al,' Glucocorticoid treatment of brain tumor patients: changes of apparent diffusion coefficient values measured by MR diffusion imaging ', Neuroradiology, Vol 46, No 10, Oct 2004

CancerWise, "Glioblastoma Brain Tumors Puzzle Doctors: Studies Continue on How to Treat Formidable Disease," Accessed 19th Nov 2007, Available at, http://www.cancerwise.org/december_2002/display.cfm?id=dbb59002-1a31-48c6-b6823d1c45bff4b8&method=displayfull&color=green

IRSA, "Astrocytomas," Accessed Nov 18th 2007, available at http://www.irsa.org/astrocytoma.html

ISCID, "The Glial Cell," Accessed Nov 18th 2007, available at http://www.iscid.org/encyclopedia/The_Glial_Cell