Epidemiology:
Incidence of Disease: The median age at diagnosis is 9 to 10 years old. These tumors occur in equal numbers in male and females. These tumors primarily occur in the in the cerebral hemispheres 65% of the time. In about 20% percent of the time in the thalamus, hypothalamus, and diencephalon. Another 15% can occur in the cerebellum and brain stem.⁶
Etiology:
Risk & Causative Factors: There is a small associated risk with exposure to vinyl chloride and to high doses of radiation therapy to the brain. Gennetics are believed to play a role in the cause of brain tumors. There is an association between hereditary syndromes and brain tumors. There is an increased frequency in families with neurofibromatosis type I.⁶
Signs & Symptoms:
Detection and Diagnosis: Headache and lethargy, increased pressure within the brain, vomiting in the morning, seizures, weakness, motor dysfunction, neuroenendocrine abnormalities, and changes in behavior.⁶
Diagnostic Procedures:
Diagnosis may be accomplished by use of physical and neurologic examinations, CT or MRI. Physical and neurological examinations are indicated with new onset of any of the symptoms listed above. CT is almost universally available and, with contrast enhancement, is a reliable screening and diagnositc method in many cases. MRI is now more frequently used in patients with malignant brain tumors and may more accurately show the extent of the tumor.⁸
Histology:
​Neuroepithelial.¹
​Please see Table 15-3 (below) for the histologic classificaton of tumors.¹

AnaplaAstroTumorClass_rev.jpg
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.³
Grading:
​World Health Organization (WHO) Grade III astrocytoma.²
​Please see Table 15-1 (below) for comparison of grades.⁴

CompGradingAstrocy_rev.jpg
Staging:
​Staging is not performed or described for patients with astrocytoma. The histologic grade of the tumor is of primary importance when determining prognosis.³
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.¹,⁷

Prognosis:
Poor Prognosis. Median survival is 2-5 years.³
Treatments:
The approach to treatment of anaplastic astrocytoma has been similar to that of gioblastoma and gross total resection is recommended if possible. Approximately 60 Gy radiation is delivered to the tumor with a 2 to 3 cm margin. There appears to be a survival benefit with adjuvant chemotherapy.¹

As with glioblastoma, many other agents have been studied in patients with newly diagnosed or recurrent anaplastic astrocytoma. Temozolomide holds great promise for this disease. For example, Yung and associates demonstrated an objective response rate of 35 % in patients with recurrent anaplastic astrocytoma, and a median oerall survival of 13.6 months from the time of recurrence.⁸

Radiation treatment fields include either the contrast-enhanced volume with a 3 cm margin or the peritumeroal edema with a 2-3 cm margin. The recommended dose is 60-64 Gy.¹

TD5/5:
The following organs have the potential of being in the treatment field depending on tumor size and location.
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

Planning Photos:
PET-CT-Hirntumor_308.jpg
CT/PET fusion for treatment planning


Digital reconstructed radiographs (DRR) of an example of 3D treatment planning conformal irradiation technique in patient with large mass in frontal region using 5 beams.⁹


Brain_ap.png
AP Beams eye view

Brain_pa.png
PA Beams eye view

Brain_rt_lat.png
RT Lat Beams eye vieew

Brain_lt_lat.png
LT Lat Beams eye view

Brain_ant_inf_oblqi.png
Anterior Inferior Oblique Beams eye view


References
1. Chao KS, Perez CA, Brady LW. Radiation Oncology - Management Decisions. 2nd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002:129-156.
2. University of Virginia Health System. http://www.healthsystem.virginia.edu/internet/braintumor/current_site/btclassification.cfm. Accessed January 14, 2010.
3. eMedicine. http://emedicine.medscape.com/article/283453-overview . Accessed January 15, 2010.
4. Prados M. Brain Cancer Atlas of Clinical Oncology. 1st ed. Hamilton, ON: BC Decker; 2002:280.
5. Wikibooks. Radiation Oncology/Toxicity/Emami. http://en.wikibooks.org/wiki/Radiation_Oncology/Toxicity/Emami . Accessed January 15, 2010.
6. Children's Hospital Boston. http://www.childrenshospital.org/az/Site565/mainpageS565P0.html. Accessed January 14, 2010.
7. Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 2nd ed. Philadelphia, PA: Mosby, Inc; 2004:736-7.
8. Rubin P. Clinical Oncology -- A Multidisciplinary Approach for Physicians and Students. Eighth edition. W.B. Saunders Company. 2001:793-809.
9. Digitally Reconstructed Radiographs courtesy of Ginnie Dea, RT(T), Alta Bates Summit Comprehensive Cancer Center.


Ginnie is bright blue.
Bridget is green.
Sheri is brown.
Zack is purple.