Ependymoma


 * **Epidemiolgy:** || Ependymomas are most common in children under the age of twelve. It accounts for approximately ten percent of childhood tumors of the central nervous system and five percent of adult intracranial gliomas. It has shown to peak at the age of five in children and thirty five in adults.[1] ||
 * **Etiology:** || Ependymomas usually arise from the ependymal area of the brain or the spinal cord. The causes of development of the tumors are unknown but the gene abnormality with the loss of chromosomes is commonly seen.[2] ||
 * **Signs & Symptoms:** || The common symptoms ependymomas are headache, nausea and vomiting, loss of appetite, temporary inability to distinguish colors, uncontrollable twitching, and temporary memory loss.[1] ||
 * **Diagnostic Procedures:** || * A complete history and general physical examination.
 * Neurological examination.
 * Brain and spine MRI. MRIs are the diagnostic procedure of choice for ependymomas, since they are more sensitive for detecting the tumor.[3]
 * Complete blood counts.
 * Assessment of mental condition, coordination, sensation, reflexes and motor and cranial nerves.[2] ||
 * **Histology:** || Ependymoma arises from the ependymal, a tissue of the central nervous system. Most ependymomas in adults are intraspinal, but in children, these tumors usually develop in the posterior fossa where they arise from the fourth ventricle ependymal cells. Grade 1 ependymomas are characterized by cuboidal to elongated tumor cells. Grade II ependymomas show no mitosis. Grade III shows increased cellularity, mitotic activity and vascular proliferation.[4] ||
 * **Lymph node drainage:** || Ependymomas rarely metastasize, but may metatasisize to extraneural tissues including lymph nodes, liver and the lungs.[5] ||
 * **Metastatic spread:** || Ependymomas may develop within the brain or spinal cord near or far from the ventricular system. The metastatic spread of ependymoma occurs infrequently. [6] ||
 * **Grading:** || Graded on a scale of I to III (World Health Organization [WHO] Grading system)

Grade I Subependymomas and myxopapillary ependymomas The myxopapillary ependymoma generally present in the spinal canal of adults. Both tumors tend to grow slowly, especially the subependymoma

Grade II and III Classic ependymomas (Grade II) and anaplastic ependymoma (Grade III). These occur mainly in the brain. These tumors grow more quickly than Grade I tumors. [2] || Supratentorial: The tumor is above the membrane that covers the cerebellum known as the tentorium cerebella. Infratentorial: The tumor is growing below the tentorium cerebella. Recurrent: A recurrent tumor is a tumor that comes back after treatment. [2] || High tone hearing loss Vestibular damage Mucositis Esophagitis Nausea and vomiting Fatigue Secondary tumor Death Neurologic deterioration: Can begin 6-12 months following radiation treatment. Radiation necrosis: Can appear after 6 months following radiation treatment with a peak at 3 years.[7] Slow growth and development Alopecia Headaches Seizures Learning disabilities Short term memory deficiency Difficulty with problem solving Loss of balance and/or trouble walking Otitis externa Serous otitis media Dermatitis Decreased visual acuity Decreased visual field Retinopathy Cataract Blindness ||
 * **Staging:** || There is no formal staging system for ependymoma; however, it can be classified based on the location of the tumor and if the cancer has spread.
 * **Radiation side effects:** || Hormone insufficiency
 * **Prognosis:** || Prognostic factors include age, tumor type, tumor grade, seizure symptoms, duration of symptoms, performance status, extent of resection, radiation doses. Neurologic function at diagnosis is an important prognostic factor.[8] Survival rates for cranial ependymomas are high (80% 5 year and 50% 10 year survival rates). [8] ||
 * **Treatments:** || Gross total surgical resection should be attempted if possible with retention of neurologic function. Total resection is attainable in approximately 50% of cases.[8] Radiation therapy is necessary when total resection is not possible and for patients with low grade tumors.[8]

Cranial ependymomas should be treated with partial brain irradiation (failure will likely occur at primary tumor location). Wedged pairs should be used to minimize dose to healthy tissue. Fields should encompass preoperative tumor volume plus a 2 centimeter margin. Doses are 54-55 Gy in 1.8 - 2.0 Gy daily fractions. Tumors in the posterior fossa may extend through the foramen magnum, so radiation treatment of the upper cervical spine should be considered.

Patients with neuraxial spread should be treated with craniospinal irradiation with a boost to the primary tumor site and gross disease. Craniospinal doses are 36-40 Gy (1.6-1.8 Gy daily fractions) with boost to 50-54 Gy.

Spinal cord ependymomas should be treated with surgical gross total resection if possible, with preservation of neurologic function. If complete resection is not possible, adjuvant radiation is necessary. In children who are still growing, a well differentiated, slow growing ependymoma may be carefully watched after partial resection, with radiation treatment only after a second surgery for recurrence. Radiation dose to 50 Gy in 1.5-2.0 Gy daily fractions. If more than half of the entire spinal cord is involved, total tumor dose should not be over 45 Gy. Smaller segments may tolerate treatment to 55 Gy. To be sure of adequate coverage, radiation fields should include two vertebral bodies above and below the tumor as demonstrated with myelogram or with MRI imaging, tumor plus 2 centimeters margin for boost.

Cervical spine: treated with lateral fields, lower energy (4-6 Mv) beams give homogeneous coverage. Thoracic spine: A direct posterior field can be used if doses to anterior structures can be limited. A mix of low and high energy beams will give homogeneous dose coverage of thoracic tumors with a PA only technique. Posterior oblique wedge pairs will offer better dose distribution for thoracic spine fields. Posterior wedged pairs or APPA may give homogeneous coverage with low energy beams. Lumbar spine: A direct posterior field can be used if doses to anterior structures can be limited. A mix of low and high energy beams will give homogeneous dose coverage of lumbar tumors with a PA only technique. Posterior oblique wedge pairs will offer better dose distribution for lumbar spine fields. Posterior wedged pairs or APPA may give homogeneous coverage with low energy beams. Female patients may benefit from lateral fields on lumbar spine fields to avoid dose to radiosensitive ovaries and uterus. Cauda equina: Ependymomas in the cauda equina are treated to a dose of 45-50 Gy and the treatment fields need to include the sacroilliac joints.

**Spinal cord dose should be calculated at multiple points along the field because of the curvature of the spine and cord.

Chemotherapy drugs have shown a benefit in children under the age of 3. Drugs that have been studied include cisplatin, etoposide, carboplatin, vincristine, cyclophosphamide and CCNU. [8] || Brain 45 Gy 50 Gy 60 Gy Brainstem 50 Gy 53 Gy 60 Gy  Cauda equina 60 Gy  Ear 55 Gy 55 Gy 55 Gy  Lens 10 Gy  Optic chiasm 50 Gy  Optic nerve 50 Gy  Retina 45 Gy  Spinal cord 47 Gy(20 cm) 50 Gy(10 cm) 50(5 cm) [8] || [2] Chao KS, Perez CA, Brady KW. //Radiation Oncology-Management Decisions//. 2nd edition. Philiadelphia, PA: Lippincott, Williams & Wilkins; 2002. [3] Grewal J, Grewal H, Kesari S. Spinal Ependymoma. MedMerits. []. Accessed June 1, 2012. [4] Vaishali SS. Histological Spectrum of Ependymomas and Correlation of p53 and Ki-67 Expression with Ependymoma Grade and Subtype. Indian Journal of Cancer. 2004; 41(2): 66-71. [5] Estlin E, Gilbertson R, Wynn R. Pediatric Hematology and Oncology: Scientific Principles and Clinical Practice. Hoboken, NJ: Wiley-Blackwell Publishing; 2010. [6] Ependymoma. Cancer.net. http://www.cancer.net/. Accessed May 29, 2012. [7] Chao KS, Perez CA, Brady LW. //Radiation Oncology-Management Decisions//. 2nd edition. Philadelphia, PA: Lippincott, Williams & Wilkins; 2002. [8] Enhard RE, Osteen RT, Gansler T. //The American Cancer Society's Clinical Oncology//. Atlanta, GA: The American Cancer Society; 2001. [9] http://www.pedsoncologyeducation.com/img/postfossaboostsag1.jpg Accessed May 30, 2012.
 * TD 5/5: || __ ORGAN WHOLE ⅔ ⅓ __
 * References: || [1] Hansen KE, Roach M. //Handbook of Evidence-Based Radiation Oncology//. 2nd Edition. New York, NY: Springer; 2010.

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