Anaplastic astrocytoma is a rare WHO grade III type of

astrocytoma Astrocytoma is a type of brain tumor. Astrocytomas (also astrocytomata) originate from a specific kind of star-shaped glial cell in the cerebrum called an astrocyte. This type of tumor does not usually spread outside the brain and spinal cord, an ...

, which is a type of cancer of the brain. 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 are 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

The best-known risk factor is exposure to ionizing radiation, and CT scan radiation is an important cause.Smoll NR, Brady Z, Scurrah KJ, Lee C, Berrington de González A, Mathews JD. Computed tomography scan radiation and brain cancer incidence. Neuro-Oncology. 2023 Jan 14;https://doi.org/10.1093/neuonc/noad012Smoll NR, Brady Z, Scurrah K, Mathews JD. Exposure to ionizing radiation and brain cancer incidence: The Life Span Study cohort. Cancer Epidemiology. 2016 Jun;42:60–5. The dose-response for the relationship between low-dose ionising radiation and anaplastic astrocytoma risk is a risk increase of 115% per 100 milligray of radiation. Most high-grade gliomas occur sporadically or without identifiable cause. However, a small proportion (less than 5%) of persons with malignant astrocytoma have a definite or suspected hereditary predisposition. The main hereditary predispositions are mainly

neurofibromatosis type I Neurofibromatosis type I (NF-1), or von Recklinghausen syndrome, is a complex multi-system neurocutaneous disorder caused by a subset of genetic mutations at the neurofibromin 1 (''NF1'') locus. Other conditions associated with mutation of the ...

, Li-Fraumeni syndrome,

hereditary nonpolyposis colorectal cancer Hereditary nonpolyposis colorectal cancer (HNPCC) is a hereditary predisposition to colon cancer. HNPCC includes (and was once synonymous with) Lynch syndrome, an autosomal dominant genetic condition that is associated with a high risk of colon ...

and

tuberous sclerosis Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combinatio ...

. Anaplastic astrocytomas have also been associated with previous exposure to

vinyl chloride Vinyl chloride is an organochloride with the formula H2C =CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. It is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC). Vinyl chloride is a ...

and to high doses of

radiation therapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a therapy, treatment using ionizing radiation, generally provided as part of treatment of cancer, cancer therapy to either kill or control the growth of malignancy, malignant cell (biology), ...

to the brain.

Pathology

Anaplastic astrocytomas fall under the category of high grade

gliomas A glioma is a type of primary tumor, primary Neoplasm, tumor that starts in the glial cells of the Human brain, brain or spinal cord. They are Malignancy, malignant but some are extremely slow to develop. Gliomas comprise about 30% of all brain ...

(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 pathologic evaluation. Compared to grade II tumors, anaplastic astrocytomas are more cellular, demonstrate more atypia, and mitoses are seen.

Treatment

The standard initial treatment is to remove as much of the tumor as possible without worsening neurologic deficits.

Radiation therapy Radiation therapy or radiotherapy (RT, RTx, or XRT) is a therapy, treatment using ionizing radiation, generally provided as part of treatment of cancer, cancer therapy to either kill or control the growth of malignancy, malignant cell (biology), ...

has been shown to prolong survival and is a standard component of treatment. There is no proven benefit to adjuvant

chemotherapy Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy re ...

or supplementing other treatments for this kind 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 area of the brain that housed the tumor. In many cases, patients with anaplastic astrocytoma may experience various types of paralysis, speech impediments, difficulties planning and skewed sensory perception. Most cases of paralysis and speech difficulties can be rehabilitated with speech, occupational, physical, and vision therapy.

Prognosis

The age-standardized 5-year relative survival rate is 23.6%. Patients with this tumor are 46 times more likely to die than matched members of the general population. It is important to note that prognosis across age groups is different especially during the first three years post-diagnosis. When the elderly population is compared with young adults, the excess hazard ratio (a hazard ratio that is corrected for differences in mortality across age groups) decreases from 10.15 to 1.85 at 1 to 3 years, meaning that the elderly population are much more likely to die in the first year post-diagnosis when compared to young adults (aged 15 to 40), but after three years, this difference is reduced markedly. Typical median survival for anaplastic astrocytoma is 2–3 years. Secondary progression to glioblastoma multiforme is common. Radiation, younger age, female sex, treatment after 2000, and surgery were associated with improved survival in AA patients.

References

{{Nervous tissue tumors Brain tumor Cancer Types of cancer Oncology