An estimated two-thirds of patients will develop scoliosis or kyphosis after surgical resection.2 Deformity most commonly occurs in the cervical spine as a result of laminectomy or weakness of spinal musculature.8 Osteoplastic laminotomy with replacement of the laminar roof is preferred over complete laminectomy to preserve the normal vertebral anatomy and reduce the incidence of postoperative scoliosis.4 Postoperative radiographs are recommended to evaluate for spinal deformity.5
Radiation therapy carries many risks, including damage to bone or the nervous system, delays in normal growth and development, endocrine abnormalities, vasculopathies, and alopecia.1,2,4,17 Toxic effects of radiation include cerebral necrosis and necrotizing leukoencephalopathy causing permanent neurologic damage.17 Additionally, radiation therapy has been estimated to carry a 25% risk of secondary tumor development over 30 years.6 Current recommendations call for the use of radiation only for malignant tumors or in cases of incomplete tumor resection or regrowth after initial resection.2,5 Craniospinal radiation is no longer used; instead radiation should be localized to the tumor and to 2-cm margins on either side of the tumor. Because radiation therapy has such toxic effects, it is not recommended for children younger than 3 years.17
Side effects of chemotherapy include myelosuppression and increased risk of infection, renal insufficiency, neurotoxicity, gonadal dysfunction, pulmonary toxicity, and hearing loss. Young children who receive chemotherapy are at risk of psychological and cognitive impairment as well.17
Prognosis Unfortunately, tumors of the CNS are the leading cause of pediatric cancer deaths.17 The outcome of spinal cord astrocytomas is primarily dependent on the histologic tumor grade (WHO classification) as well as the preoperative neurologic status of the patient.4 Because the child's condition at the time of surgery is the best indicator of surgical outcome,7 early-stage diagnosis of spinal cord astrocytoma is necessary in order to preserve neurologic function and improve prognosis.14
The best predictor of survival in patients with astrocytoma is the histologic grade of the tumor.7 The five-year survival rate for low-grade astrocytomas ranges from 60% to 90%,8 while high-grade lesions are associated with a worse prognosis.18 In a study of 231 children with highgrade astrocytomas of either the brain or spinal cord treated with a combination of surgery, radiation, and chemotherapy, the 5-year survival rate was only 36.6%.18 The 5-year survival rate in the previously noted retrospective study of 10 patients was significantly higher (68%).1 This was a smaller study, involving eight patients with low-grade lesions and two with high-grade lesions. Death from highgrade astrocytomas usually occurs within 2 years of diagnosis due to disease progression or dissemination into the leptomeninges (pia mater and arachnoid mater). Tumor progression often leads to hydrocephalus or respiratory failure from paralysis, and 58% of patients with grade III or grade IV tumors will die of hydrocephalus or leptomeningeal metastases. Other causes of death include pulmonary embolism and pneumonia secondary to prolonged immobility.7,8
CONCLUSION
Although rare overall, astrocytoma is the most commonly diagnosed IMSCT in the pediatric population. Most intramedullary astrocytomas occur in the cervicothoracic spine. Symptoms include back pain, sensory and motor dysfunction, and spinal cord deformity. The diagnosis is made by contrast and noncontrast MRI as well as tumor biopsy. Surgical intervention is the treatment of choice, although it is difficult to completely resect the solid tumor because of the infiltrative nature of astrocytomas. Adjunct therapies, including radiation and chemotherapy, have also been studied for use in the treatment of astrocytomas. However, more research is needed to determine the role of these therapies in children. The prognosis of astrocytomas is dependent upon the histologic tumor grade as well as the child's functional status at diagnosis. Unfortunately, the prognosis of high-grade astrocytomas is poor. As clinicians, we must consider spinal cord astrocytoma in the differential diagnosis of any child with back pain, as diagnosis at an earlier stage improves survival and functional outcome. JAAPA
Johanna Chelcun is a PA in hospital medicine at Montefiore Medical Center, Bronx, New York. Richard Pope is a senior rheumatology PA at the Arthritis Center of Connecticut, Waterbury, Connecticut, and an adjunct professor at the Quinnipiac University PA program in Hamden, Connecticut. The authors have indicated no relationships to disclose relating to the content of this article.
DRUGS MENTIONED
Carboplatin (Paraplatin, generics)
Cisplatin (Platinol, generics)
Cytarabine (Cytosar-U, DepoCyt, generics)
Etoposide (Etopophos, VePesid, generics)
Fentanyl (Sublimaze, generics)
Ifosfamide (Ifex)
Lomustine (CeeNU)
Methotrexate
Propofol (Diprivan, generics)
Temozolomide (Temodar)
Vincristine (Oncovin, Vincasar)
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