Brain cancer in children

Over the past three decades, according to the International Agency for Research on Cancer (IARC), a significant increase in the proportion of oncological diseases occurring in childhood has caused particular concern. At the same time, brain cancer in children (along with leukemia) is the most common pathology.

Primary, i.e. initially developing pathological neoplasm in the brain, is typical for children. While metastatic (or secondary) brain cancer in children is diagnosed much less frequently.

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Causes of Brain Cancer in Children

It is generally accepted that the etiology of malignant neoplasms of various localizations is associated with a disruption of the body's anti-cancer defenses, which occurs as a result of immune system failures when exposed to carcinogenic factors. Most often, this is what leads to the mutation of healthy cells. However, reliable causes of brain cancer in children, or rather primary cancer, have not been established to date. And secondary brain cancer appears when other organs are affected - as metastases.

For example, secondary brain cancer in children develops in the presence of retinoblastoma, a genetically determined congenital neoplasia of the retina, which usually occurs between the ages of 18 and 2.5 years.

Experts attribute the effects of ionizing and long-wave ultraviolet radiation, as well as the carcinogenic effects of certain chemicals (formaldehyde, vinyl chloride, asbestos, benzopyrene, arsenic compounds, chromium, nickel, etc.) to factors that increase the risk of developing malignant brain tumors in children.

Among the indirect causes of brain cancer in children, diseases that reduce the immune system's defenses, as well as the presence of oncological diseases in the family history, play an important role. Although, according to clinical statistics, the hereditary factor in the etiology of brain cancer in children is noted in only 5% of cases.

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Symptoms of Brain Cancer in Children

The most common forms of primary brain cancer in children are gliomas (astrocytomas) and medulloblastomas.

In glioma, the tumor develops in the glial cells of the cerebellum and brainstem - astrocytes. Medulloblastoma (melanotic or lipomatous granuloblastoma) is a congenital brain tumor localized in the middle and in the hemispheres of the cerebellum. This form of brain cancer usually develops in children aged two to ten years, but is often diagnosed in adolescents.

Taking into account the size of the lesion, its most typical location and the stage of the disease, the following symptoms of brain cancer in children are noted:

• constant headaches (in the morning - intense);
• weakness, increased fatigue, apathy and drowsiness;
• decreased appetite and body weight;
• nausea and vomiting;
• impaired coordination of movements;
• convulsions, fainting and hallucinations;
• partial unilateral paralysis (hemiparesis);
• decreased sensitivity of one half of the body (hemihypesthesia);
• speech disorders, decreased vision and double vision
• behavioral deviations
• accumulation of excess cerebrospinal fluid in the cranial cavity (hydrocephalus).

Diagnosis of brain cancer in children

All methods of diagnosing brain cancer in children are aimed at determining the specific type of tumor, its exact location and the extent of tissue damage.

First of all, the doctor examines the patient and checks his neurological functions - reflex reactions, muscle tone, coordination of movements, etc. To detect possible inflammation of the optic nerve, an eye examination should be performed (using an ophthalmoscope).

In order to differentiate neoplasms for their malignant pathogenesis, as well as to determine the tumor localization, a brain examination is mandatory using modern visualization methods such as CT (computer tomography) and MRI (magnetic resonance imaging). Data on the malignant nature of neoplasms are also obtained using a histological examination of tumor tissue, for which a biopsy is required.

According to neuro-oncologists, a biopsy to diagnose brain cancer in children is a serious surgical intervention performed under general anesthesia. During this operation, it is possible not only to take a tissue sample for examination, but also - depending on the nature of the tumor - to try to remove it. But this is quite rare.

MRS - magnetic resonance spectroscopy - is performed to identify tumor cell metabolites and determine the type of brain cancer in children. And to determine the extent of the spread of cancer cells and the level of intracranial pressure, a spinal (lumbar) puncture is performed under local anesthesia.

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Treatment of brain cancer in children

Symptomatic treatments for brain cancer in children include: corticosteroids to reduce brain tissue swelling, and anticonvulsants to stop muscle spasms. All other treatments are aimed directly at the cancerous tumor. These include surgical removal of the tumor, radiation therapy, and chemotherapy.

Chemotherapy is performed by administering special medications aimed at destroying cancer cells. These can be oral medications (in tablets or capsules), injections that are administered into a vein, muscle or artery, as well as into the cerebrospinal fluid. It should be noted that in most cases, chemotherapy is prescribed after surgery or radiation.

Surgical treatment of brain cancer in children is performed by neurosurgeons of specialized clinics. To remove the tumor, a craniotomy or craniotomy is performed to access the brain, after which the maximum volume of tissue affected by cancer is excised, but in such a way as not to affect healthy areas of the brain and its important centers.

Radiotherapy or standard stereotactic radiotherapy for brain cancer in children involves external radiation exposure to the tumor. It should reduce the size of the tumor. And after surgery to remove the tumor, it should prevent the growth of cancer cells remaining in the brain.

Until recently, radiation therapy was the method of choice when it was impossible to get rid of brain cancer by surgery. But now there is an alternative to surgical tumor removal - three-dimensional conformal radiation therapy (IMRT) and radiosurgery using the CyberKnife.

These non-invasive oncological technologies consist of the fact that the brain tumor is subjected to the most precisely targeted (thanks to computer detection and clear imaging of the tumor borders) and optimally dosed radiation, which kills cancer cells.

Chemotherapy for brain cancer in children

The main drugs currently used in chemotherapy for brain cancer in children include Carmustine, Temozolomide (Temodal), Lomustine, Vincristine, Bevacizumab (Avastin).

The antitumor drug Carmustine acts cytostatically, i.e. it penetrates cancer cells, reacts with their nucleotides, inhibits enzyme activity and disrupts DNA synthesis. Thus, mitosis (indirect cell division) of the tumor stops.

The treatment is carried out by a doctor, who determines the dose based on the level of leukocytes and platelets in the blood plasma. Carmustine in the form of a solution is administered intravenously; an hour or two after its administration, facial hyperemia (due to blood flow), nausea and vomiting appear. Further side effects of the drug are observed, such as loss of appetite, diarrhea, difficult and painful urination, abdominal pain, changes in the blood (leukopenia, thrombocytopenia, anemia, acute leukemia), bleeding and hemorrhage, edema, skin rash, ulcers on the oral mucosa, etc.

When treating brain cancer in children with Carmustine – as with many other cytostatic anticancer drugs – there is a high probability of developing cumulative blood toxicity. Chemotherapy courses are given once every 6 weeks – to restore the hematopoietic function of the bone marrow. In addition, if this cancer drug has been used for a sufficiently long time, the probability of a “remote effect” in the form of the appearance of secondary cancerous tumors, including acute leukemia, cannot be ruled out.

Temozolomide (other trade names - Temodal, Temomid, Temcital) is available in capsules, acts on a similar principle and has almost the same side effects as Carmustine. Use in the treatment of brain cancer in children under three years of age is limited. The drug Lomustine is also intended for oral use. The dosage for both children and adults with brain tumors is selected by the doctor individually and is constantly adjusted during treatment - depending on the therapeutic effect, as well as taking into account the severity of intoxication. The side effects of Lomustine are the same as those of Carmustine.

Cytostatic drug for intravenous injections - Vincristine - is of plant origin and is an alkaloid of pink periwinkle. The dosage is individual, but the average weekly dose for children is 1.5-2 mg per square meter of body surface, and for children weighing up to 10 kg - 0.05 mg per kilogram of weight.

Side effects of Vincristine treatment are expressed in the form of increased or decreased blood pressure, convulsions, headaches, shortness of breath, bronchospasm, decreased muscle tone, sleep disorders, nausea, vomiting, stomatitis, intestinal obstruction, atony of the bladder and urinary retention, swelling, etc. However, the negative impact of Vincristine on the hematopoietic system is much less significant than that of the drugs mentioned above.

In case of relapse of glioblastoma – one of the most common forms of brain cancer in children and adults – an antitumor drug in the form of an infusion solution Bevacizumab (Avastin) is prescribed. This drug is a recombinant monoclonal antibody. It is capable of interfering with certain biochemical processes in cancer cells, blocking its growth. Due to the low distribution volume and long half-life, Bevacizumab (Avastin) is used once for 2-3 weeks (intravenously and only by drip). Side effects of Bevacizumab include increased blood pressure; gastrointestinal perforation; hemorrhage; rectal, pulmonary and nasal bleeding; arterial thromboembolism; leukopenia and thrombocytopenia; skin discoloration, increased lacrimation, etc. But all these side effects are not as intense as those of most drugs for the drug treatment of brain cancer in children.

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Prevention of brain cancer in children

According to doctors, since the etiology of this disease has not been precisely established, prevention of brain cancer in children is impossible.

However, it should be kept in mind that there is already considerable evidence that vitamins A, C, E, β-carotene (provitamin A), as well as compounds of the chemical element selenium (Se, atomic number 34) have a strong anti-carcinogenic effect on the body. So these substances should be used for primary prevention of cancer.

By the way, selenium is found in meat, liver, lard, milk (and dairy products), seafood, as well as in cereals and legumes, mushrooms, olive oil and almost all nuts.

Childhood Brain Cancer Prognosis

Brain cancer in children develops very quickly. For many sick children whose malignant brain tumors – glioma or medulloblastoma – were detected late, therapeutic intervention can reduce the symptoms of the deadly disease and prolong life with the help of constant medical monitoring of the tumor.

But at the same time, brain cancer in children, compared to similar tumors in adults, is treated more successfully. Therefore, this diagnosis is not a death sentence. The main thing is to detect cancer in time and make every effort to fight it.