Gliomas

Gliomas are primary tumors that develop from the brain parenchyma. Symptoms and diagnosis are the same as for other brain tumors.

Treatment of gliomas is surgical, radiological, and for some tumors, chemotherapeutic.

Excision rarely results in a cure.

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Symptoms glioma

Symptoms and signs of the disease depend on the location.

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Forms

Gliomas include astrocytomas, oligodendrogliomas, medulloblastomas, and ependymomas. Many gliomas infiltrate brain tissue diffusely and irregularly.

For all astrocytomas, the universal grading system (WHO) is used according to the histological criterion of "grade of malignancy". Grade 1 (astrocytoma): there should be no signs of anaplasia. Grade 2 (astrocytoma): 1 sign of anaplasia, most often nuclear atypia. Grade 3 (anaplastic astrocytoma): 2 signs, most often nuclear atypia and mitoses. Grade 4 (glioblastoma): 3-4 signs - nuclear atypia, mitoses, vascular endothelial proliferation and/or necrosis.

Astrocytomas are the most common gliomas. In order of increasing severity, they are classified as grades 1 and 2 (low-grade astrocytomas: pilocytic and diffuse), grade 3 (anaplastic astrocytomas), and grade 4 (glioblastomas, including the most malignant glioblastoma multiforme). Astrocytomas 1-3 tend to develop in younger individuals and may degenerate into secondary glioblastomas. Glioblastomas are composed of chromosomally heterogeneous cells. Primary glioblastomas develop de novo, usually in middle or old age. The genetic characteristics of primary and secondary glioblastomas may change as the tumor evolves.

Oligodendrogliomas are the most benign tumors. They primarily affect the cerebral cortex, especially the frontal lobes.

Medulloblastomas occur mainly in children and young adults, usually in the region of the fourth ventricle. Ependymomas are rare, occurring mainly in children, usually in the region of the fourth ventricle. Medulloblastomas and ependymomas predispose to occlusive hydrocephalus.

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Diagnostics glioma

The diagnosis is the same as for other brain tumors.

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Treatment glioma

Anaplastic astrocytomas and glioblastomas are treated with surgery, radiation, and chemotherapy to reduce tumor mass. Removal of as much tumor mass as possible is safe, prolongs survival, and improves neurologic function. After surgery, radiation therapy is indicated at a course dose of 60 Gy per tumor in the form of conformal radiation therapy, which targets the tumor and spares normal brain tissue. Chemotherapy is carried out with nitrosoureas (eg, carmustine, lomustine) alone or in combination. Instead of combination chemotherapy, temozolomide can be given 5 days a month at 150 mg/m orally once a day in the first month and 200 mg/m in the following months.

During chemotherapy, a complete blood count should be taken at least 24 or 48 hours before each session. New techniques (eg, chemotherapy capsules, stereotactic radiosurgery, new chemotherapeutic agents, gene or immune therapy) should be considered. After combination therapy, the survival rate for anaplastic astrocytomas or glioblastomas is 1 year in 50% of cases, 2 years in 25%, and 5 years in 10-15%. Favorable prognostic factors include age under 45 years, anaplastic astrocytoma histology rather than glioblastoma multiforme, complete or nearly complete tumor resection, and evidence of improved neurologic function after surgery.

Low-grade astrocytomas are excised if possible and then irradiated. The timing of radiation therapy is a matter of debate: early treatment is more effective, but also carries the risk of earlier neurotoxicity. Five-year survival is achieved in 40-50% of cases.

Oligodendrogliomas are treated surgically and radiologically, as are low-malignancy astrocytomas. Chemotherapy is sometimes used. Five-year survival is achieved in 50-60% of cases.

Medulloblastomas are treated with whole-brain irradiation at a dose of approximately 35 Gy, posterior cranial fossa - 15 Gy, and spinal cord - 35 Gy per course. Chemotherapy is prescribed as an adjuvant treatment and in case of relapses. Nitrosourea derivatives, procarbazine, vincristine are prescribed separately and in combination, intrathecal methotrexate, combined polychemotherapy (for example, according to the MOPP protocol: mechlorethamine, vincristine, procarbazine and prednisolone), cisplatin and carboplatin, but none of the schemes gives a sustainable effect. Five-year survival is achieved in 50% of cases, and 10-year survival in 40%.

Ependymomas are usually treated with surgery to excise the tumor and restore the CSF drainage pathway, followed by radiation therapy.

In histologically benign ependymomas, radiation therapy is directed at the tumor itself; in malignant tumors and incomplete tumor removal, the entire brain is irradiated during surgery. If there are signs of seeding, both the brain and spinal cord are irradiated. The degree of completeness of tumor excision determines survival. After treatment, 5-year survival can be achieved in 50% of cases, and in more than 70% of cases if the tumor is completely removed.