Astrocytoma natural history
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Risk calculators and risk factors for Astrocytoma natural history |
Overview
Natural History
Complications
Prognosis
Low-grade astrocytomas
- Low-grade astrocytomas (grade I [pilocytic] and grade II) have a relatively favorable prognosis, particularly for circumscribed, grade I lesions where complete excision may be possible.[11,12,51-55] Tumor spread, when it occurs, is usually by contiguous extension; dissemination to other CNS sites is uncommon, but does occur.[56,57] Although metastasis is uncommon, tumors may be of multifocal origin, especially when associated with NF1.
- Unfavorable prognostic features for childhood low-grade astrocytomas include the following:[58,59]
- Young age.
- Fibrillary histology.
- Inability to obtain a complete resection.
- In patients with pilocytic astrocytoma, elevated MIB-1 labeling index, a marker of cellular proliferative activity, is associated with shortened PFS.[8] A BRAF-KIAA fusion, found in pilocytic tumors, confers a better clinical outcome.[28]
- Children with isolated optic nerve tumors have a better prognosis than those with lesions that involve the chiasm or that extend along the optic pathway.[60-63]; [64][Level of evidence: 3iiC] Children with NF1 also have a better prognosis, especially when the tumor is found in asymptomatic patients at the time of screening.[60,65]
High-Grade Astrocytomas
- Biologic markers, such as p53 overexpression and mutation status, may be useful predictors of outcome in patients with high-grade gliomas.[5,66,67] MIB-1 labeling index is predictive of outcome in childhood malignant brain tumors. Both histologic classification and proliferative activity evaluation have been shown to be independently associated with survival.[68]
- Although high-grade astrocytomas generally carry a poor prognosis in younger patients, those with anaplastic astrocytomas in whom a gross-total resection is possible may fare better.[53,69,70]
- For low grade astrocytomas, removal of the tumor will generally allow functional survival for many years.
- In some reports, the five-year survival has been over 90% with well resected tumors.
- To date, complete resection of high grade astrocytomas is impossible because of the diffuse infiltration of tumor cells into normal parenchyma. Thus, high grade astrocytomas inevitably recur after initial surgery or therapy, and are usually treated similarly as the initial tumor.