What is it ?
Anaplastic oligoastrocytoma, or anaplastic astrocytoma, is a malignant tumor of the brain. It is specifically a glioma, that is to say a tumor from the nervous tissue, in the brain or spinal cord. The World Health Organization classifies gliomas from I to IV, according to their morphology and degree of malignancy. Anaplastic astrocytomas represent grade III, between grades I and II considered benign and glioblastomas (grade IV). Anaplastic Astrocytoma may result from the complication of a grade II benign tumor or may develop spontaneously. It has a strong tendency to progress to glioblastoma (grade IV) and life expectancy is approximately two to three years, despite treatment with surgery and radiotherapy / chemotherapy. Anaplastic anatomy and glioblastomas affect 5 to 8 per 100,000 people in the global population.
Most symptoms of anaplastic oligoastrocytoma result from increased pressure in the brain, caused either by the tumor itself or by the abnormal accumulation of cerebrospinal fluid it causes. Symptoms vary depending on the exact location and size of the tumor:
- Memory disorders, personality changes and hemiplegia when the tumor develops in the frontal lobe;
- Seizures, impaired memory, coordination and speech when in the temporal lobe;
- Motor disorders and sensory abnormalities (tingling and burning) when in the parietal lobe;
- Visual disturbances when the tumor concerns the occipital lobe.
The origins of the disease
The precise cause of anaplastic astrocytoma is unknown to date, but researchers believe that it is the result of a combination of genetic predisposition and environmental triggers of the disease.
Anaplastic oligoastrocytoma is slightly more common in men than women and often occurs between 30 and 50 years of age. It should be noted, however, that the disease is likely to affect children, usually between 5 and 9 years of age. Anaplastic astrocytomas and glioblastoma multiforme (grades III and IV) represent about 10% of childhood tumors in the central nervous system (80% of these tumors being grade I or II).
Hereditary genetic diseases such as neurofibromatosis type I (Recklinghausen disease), Li-Fraumeni syndrome, and tuberous sclerosis of Bourneville increase the risk of developing anaplastic astrocytoma.
As with many cancers, environmental factors such as exposure to ultraviolet light, ionizing radiation and certain chemicals, as well as poor diet and stress are considered risk factors.
Prevention and treatment
The treatment of anaplastic oligoastrocytoma depends essentially on the general condition of the patient, the location of the tumor and the speed of its progression. It involves surgery, radiation and chemotherapy alone or in combination. The first step is to perform a surgical removal of as much of the tumor as possible (resection), but this is not always possible because of the previously mentioned parameters. After surgery, radiotherapy and possibly chemotherapy are used to try to remove tumor residues if, for example, malignant cells have spread to brain tissue.
The prognosis is related to the state of health of the patient, the characteristics of the tumor, and the response of the body to chemotherapy and radiotherapy treatments. Anaplastic astrocytoma has a strong tendency to progress to glioblastoma in about two years. With standard therapy, the median survival time of people with anaplastic astrocytoma is two to three years, which means that half of them will die before this time.