Anaplastic astrocytoma

Anaplastic astrocytoma
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Field	Neurosurgery
Symptoms
Complications
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Duration
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Differential diagnosis
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Rare genetic disorder affecting albumin production

Anaplastic Astrocytoma

Anaplastic astrocytoma is a rare WHO grade III type of astrocytoma, which is a type of brain tumor. In the United States, the annual incidence rate for anaplastic astrocytoma is 0.44 per 100,000 people.

Signs and Symptoms

Initial presenting symptoms most commonly include headache, depressed mental status, focal neurological deficits, and/or seizures. The growth rate and mean interval between onset of symptoms and diagnosis is approximately 1.5–2 years but is highly variable, being intermediate between that of low-grade astrocytomas and glioblastomas. Seizures are less common among patients with anaplastic astrocytomas compared to low-grade lesions.

Causes

Most high-grade gliomas occur sporadically or without identifiable cause. However, a small proportion (less than 5%) of individuals with malignant astrocytoma have a definite or suspected hereditary predisposition. The main hereditary predispositions include neurofibromatosis type I, Li-Fraumeni syndrome, hereditary nonpolyposis colorectal cancer, and tuberous sclerosis. Anaplastic astrocytomas have also been associated with previous exposure to vinyl chloride and high doses of radiation therapy to the brain.

Pathology

Anaplastic astrocytomas are classified as high-grade gliomas (WHO grade III-IV), which are pathologically undifferentiated gliomas that carry a poor clinical prognosis. Unlike glioblastomas (WHO grade IV), anaplastic astrocytomas lack vascular proliferation and necrosis on pathological evaluation. Compared to grade II tumors, anaplastic astrocytomas are more cellular, exhibit more atypia, and display increased mitotic activity.

Treatment

The standard initial treatment involves surgical resection to remove as much of the tumor as possible without worsening neurological deficits. Radiation therapy has been shown to prolong survival and is a standard component of treatment. There is no proven benefit to adjuvant chemotherapy or supplementing other treatments for this type of tumor. Although temozolomide is effective for treating recurrent anaplastic astrocytoma, its role as an adjuvant to radiation therapy has not been fully tested.

Quality of life after treatment depends heavily on the affected area of the brain. In many cases, patients with anaplastic astrocytoma may experience various types of paralysis, speech disorders, difficulties in executive function, and altered sensory perception. Most cases of paralysis and speech difficulties can be rehabilitated with speech therapy, occupational therapy, physical therapy, and vision therapy.

Prognosis

The age-standardized 5-year relative survival rate for anaplastic astrocytoma is 23.6%. Patients with this tumor are significantly more likely to succumb to the disease compared to matched members of the general population. Prognosis varies across age groups, particularly during the first three years post-diagnosis. Older adults are at a significantly higher risk of mortality within the first year post-diagnosis compared to young adults (aged 15 to 40), but after three years, this difference is markedly reduced.

Typical median survival for anaplastic astrocytoma is 2–3 years. Secondary progression to glioblastoma multiforme is common. Factors associated with improved survival in anaplastic astrocytoma patients include radiation therapy, younger age, female sex, treatment after the year 2000, and surgery.