Low+Grade+Astrocytoma

•protoplasmic •gemistocytic •fibrillary •mixed || ​Please see Table 15-1 for comparison of grades.³
 * Epidemiology: || Incidence of Disease: The median age for patients diagnosed with low grade astrocytomas, is about 35 years old. In the United States these tumors are slightly more common in whites. There is also a slight male predominance (55% - 65%).² ||
 * Etiology: || Risk & Causative Factors: Their cause is unknown, and current research indicates that the environment does not seem to play a role in their origin. Families with neurofibromatosis are at an increased risk of developing these tumors.² ||
 * Signs & Symptoms: || Detection and Diagnosis: headache, seizure, elevating intercranial pressure (ICP) caused by mass effect or obstructing cerebrospinal fluid (CSF), hydrocephalus, neurologic abnormalities, paralysis, sensory deficits,and odd behavior.² ||
 * Diagnostic Procedures: || The first step in evaluating patients suspected of having an astrocytoma is MRI. This could be performed in any adult who presents with an unprovoked seizure for which no immediate explanation is available. A normal MRI scan essentially rules out a diffuse astrocytoma. Difficulty in interpreting the MRI scan may occur in older patients who have multiple areas of white-matter hyperintensity related to vascular disease. Usually, malignant gliomas, glioblastoma multiforme, and anaplastic tumors contrast enhance whereas lower-grade tumors do not.⁶ ||
 * Histology: || ​Four histologic variants of low-grade astrocytoma are recognized:²
 * Lymph Node Drainage: || Absence of lymphatics in the brain; therefore no lymphatic drainage due to the blood brain barrier. ||
 * Metastatic Spread: || Unlike other systemic tumors, distant or extracranial metastasis of astrocytomas is exceedingly rare. Clinical decline and tumor associated morbidity and mortality are almost always associated with local mass effects on the brain by a locally recurrent intracranial tumor.² ||
 * Grading: || World Health Organization (WHO) Grade II astrocytoma.²

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 * Staging: || Staging is not performed or described for patients with astrocytoma. The histologic grade of the tumor is of primary importance when determining prognosis.² ||
 * Radiation Side Effects: || The following side effects are possible with irradiation to the brain. The presence of these side effects varies due to tumor location, tumor size, and treatment technique/total dose.

Fatigue, decrease in blood counts, nausea, vomiting, headaches, skin irritation (on scalp) and short term memory loss can all occur during and shortly after the course of radiation treatment. Hair loss (temporary or permanent) can occur with doses of 20-40 Gy and doses greater than 40 Gy, respectively. Hormone insufficiency (if pituitary gland is in the field) will occur at a dose of 20 Gy. If the retina or lens is in the field, doses greater than 54 Gy can result in vision changes, cataracts or blindness. Serous otitis can occur when the ear falls in the treatment field at doses of 50 Gy. Neurologic deteriorations may be noticeable 6-12 weeks after treatment. Radiation necrosis may become evident 6 months to 3 years post radiation treatment.¹,⁴ || 5 year survival rate is 65-85% 10 year survival rate is 20-45% -Younger age, better performance status, and lower grade tumors all have a positive influence on prognosis. -Total resection also has a positive influence on prognosis.² || The treatment of patients with low-grade astrocytomas is controversial. Some clinicians would argue that patients who are otherwise well, and who present with CT or MRI findings consistant with a low-grade astrocytoma, may be observed without biopsy. In symptomatic patients, gross total resection improves the outcome. Likewise, radiation therapy treatment of low-grade astrocytoma is controversial. Most of the studies are retrospective reviews, and the groups of patients who are or are not treated with radiation therapy are not comparable. In general, most retrospective studies suggest a benefit to postoperative radiation therapy following incomplete resection, especially if the patients are symptomatic or older than 35 to 40 years of age. However, following complete resection, the benefit of radiation is more controversial and may be reserved until recurrence. The recommended post-op radiation dose is 50-55 Gy. There is no proven benefit of chemotherapy in the treatment of low-grade astrocytomas.⁷ || Brain: 45Gy (whole), 50Gy (2/3), 60Gy (1/3) Brainstem (large tumors): 50Gy (whole), 53Gy (2/3), 60Gy (1/3) Ear (acute serous otitis): 30Gy Ear (chronic serous otitis): 55Gy Lens: 10 Gy Optic Chiasm: 50 Gy Optic Nerve: 50 Gy Retina: 45 Gy⁵ || Photos: || Images of 3D treatment planning conformal irradiation technique using rapid arc in patient with brainstem mass.⁸
 * Prognosis: || Median survival: 7.5 years
 * Treatments: || **Surgery**
 * Radiation therapy**
 * Chemotherapy**
 * TD5/5: || The following organs have the potential of being in the treatment field depending on tumor size and location.
 * Planning





|| 1. Chao KS, Perez CA, Brady LW. //Radiation Oncology - Management Decisions.// 2nd ed. Philadelphia, PA//:// Lippincott, Williams & Wilkins; 2002:129-156. 2. eMedicine. http://emedicine.medscape.com/article/1156429-overview. Accessed January 15, 2010. 3. Prados M. //Brain Cancer Atlas of Clinical Oncology.// 1st ed. Hamilton, ON: BC Decker; 2002:280. 4. Washington CM, Leaver D. //Principles and Practice of Radiation Therapy//. 2nd ed. Philadelphia, PA: Mosby, Inc; 2004:73-7. 5. Wikibooks. Radiation Oncology/Toxicity/Emami. []. Accessed January 15, 2010. 6. Lenhard RE, Osteen RT, Gansler T. //The American Cancer Society's Clinical Oncology//. American Cancer Society; 2001:666. 7. Rubin P. //Clinical Oncology -- A Multidisciplinary Approach for Physicians and Students.// Eighth edition. W.B. Saunders Company; 2001:810. 8. Digitally Reconstructed Radiographs courtesy of Ginnie Dea, RT(T), Alta Bates Summit Comprehensive Cancer Center.
 * References**

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