Brain cancer in children

Over the past three decades, according to the International Agency for Research on Cancer (IARC), a significant concern is a significant increase in the proportion of cancer caused in childhood. In this case, brain cancer in children (along with leukemia) is the most common pathology.

For children, the primary, that is, initially developing in the brain pathological neoplasm, is characteristic. While metastatic (or secondary) brain cancer in children is diagnosed much less often.

[1], [2], [3], [4], [5]

Causes of brain cancer in children

It is considered that the etiology of malignant tumors of different localization is associated with a disruption of the work of the anticancerogenic protection of the organism, which occurs as a result of failures of the immune system when exposed to carcinogenic factors. Most often this leads to a mutation of healthy cells. However, reliable causes of brain cancer in children, or, more accurately, primary cancer, have not been established to date. A secondary brain cancer appears when other organs are affected - like 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 up to 2.5 years.

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

Among the indirect causes of brain cancer in children, an important role is played by diseases that reduce the protective forces of immunity, as well as the presence of cancer in the family history. Although, according to clinical statistics, a hereditary factor in the etiology of brain cancer in children is noted in only 5% of cases.

[6], [7]

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 glial cells of the cerebellum and brainstem - astrocytes. Medulloblastoma (melanotic or lipomatous granuloblastoma) is an innate brain tumor with localization in the middle and hemispheres of the cerebellum. This form of brain cancer, as a rule, develops in children aged from two to ten years, but is often diagnosed in adolescents.

Given the size of the lesion, its most typical localization and stage of the disease, there are such symptoms of brain cancer in children:

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

Diagnosis of brain cancer in children

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

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

In order to differentiate neoplasms for their malignant pathogenesis, and also to locate the tumor, it is necessary to conduct brain research using modern imaging techniques such as CT and MRI. Data on the malignant nature of neoplasia are also obtained by histological examination of tumor tissues, which requires a biopsy.

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

MRS - Magnetic Resonance Spectroscopy - is conducted to identify metabolites of tumor cells 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 under local anesthesia, a spinal (lumbar) puncture is performed.

[8], [9], [10]

Treatment of brain cancer in children

Among the symptomatic means of treating brain cancer in children are used: to reduce swelling of the brain tissue - corticosteroid drugs, for arresting attacks of muscle cramps - anticonvulsant drugs (anticonvulsants). All other methods of treatment are directed directly at the cancerous tumor. This is surgical removal of the neoplasm, radiation therapy and chemotherapy.

Chemotherapy is carried out by the introduction of special medications aimed at the destruction of cancer cells. These can be oral medications (in tablets or capsules), injections that are injected into a vein, muscle or artery, as well as into a cerebrospinal fluid. It should be noted that in most cases, chemotherapy is prescribed after surgical intervention or after irradiation.

Treatment of brain cancer in children is performed surgically by neurosurgeons of specialized clinics. To remove the tumor, craniotomy or trepanation of the skull necessary to access the brain is made, after which the maximum volume of cancer-affected tissues is excised, but so as not to affect the healthy parts of the brain and its important centers.

Radiation therapy or standard stereotactic radiotherapy of brain cancer in children involves external radioactive irradiation of the tumor. It should reduce the size of the tumor. And after the operation to remove the tumor - to prevent the growth of the remaining cancer cells in the brain.

Until recently, radiotherapy was the method of choice if it was impossible to get rid of brain cancer in an operative way. But now there is an alternative to surgical removal of the tumor - three-dimensional conformal radiation therapy (IMRT) and radiosurgery with the help of a cyber knife.

These non-invasive oncology technologies consist in the fact that the brain tumor undergoes the most accurately directed (due to computer detection and clear imaging of the tumor boundaries) and the optimal dose of radiation that kills cancer cells.

Chemotherapy for brain cancer in children

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

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

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, there is hyperemia of the face (due to hot flashes), nausea and vomiting. Further, there are side effects of the drug, such as loss of appetite, diarrhea, difficult and painful urination, abdominal pain, changes in the blood (leukopenia, thrombocytopenia, anemia, acute leukemia), bleeding and hemorrhage, swelling, skin rash, ulcers oral mucosa, etc.

In the treatment of brain cancer in children with the help of Carmustine - like many other anti-cancer drugs-cytostatics - the likelihood of developing cumulative toxicity of the blood. Chemotherapy courses are held once every 6 weeks - to restore the hematopoietic function of the bone marrow. In addition, if this remedy for cancer has been used for a fairly long time, the probability of a "distant effect" in the form of the appearance of secondary cancers, including acute leukemia, is not ruled out.

Temozolomide (other trade names - Temodal, Temomide, Temtital) is available in capsules, operates on a similar principle and has almost the same side effects as Carmustine. The use in the treatment of brain cancer in children under the age of three is limited. The drug Lomustine is also intended for oral use. Selection of the dose for children and adults with brain tumors is carried out by the doctor individually and during the treatment is constantly adjusted - depending on the therapeutic effect, and also taking into account the severity of the intoxication. Side effects of Lomustin are the same as those of Carmustine.

Cytostatic drug for intravenous injections - Vincristine - is of vegetable origin and is an alkaloid of vinca pink. Dosage individually, but the average weekly dose for children is 1.5-2 mg per square meter. Meter body surface, and for children weighing up to 10 kg - 0.05 mg per kilogram of weight.

Side effects in the treatment of Vincristine are expressed in the form of increased or decreased blood pressure, seizures, headache, dyspnea, bronchospasm, weakening of muscle tone, sleep disorders, nausea, vomiting, stomatitis, intestinal obstruction, bladder atony and urinary retention, puffiness, etc. However The negative impact of Vincristine on the hemopoietic system is much less significant than that of the drugs mentioned above.

When relapsing glioblastoma - one of the most common forms of brain cancer in children and adults - an antitumor drug is administered in the form of a solution for the infusions of Bevacizumab (Avastin). This agent is a recombinant monoclonal antibody. It is capable of intervening in certain biochemical processes in the cells of a cancerous tumor, blocking its growth. Due to the low volume of distribution and the long half-life of Bevacizumab (Avastin) is used once for 2-3 weeks (intravenously and only drip). Among the side effects of Bevacizumab, there was an increase in blood pressure; perforation of the gastrointestinal tract; 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 most drugs for 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 is not exactly established, prevention of brain cancer in children is impossible.

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

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

Prognosis of brain cancer in children

Brain cancer in children develops very quickly. Many sick children who have a malignant brain tumor - glioma or medulloblastoma - were discovered untimely, the therapeutic effect can weaken the manifestation of the symptoms of a deadly disease and prolong life by constant medical monitoring of the tumor.

But at the same time, brain cancer in children, compared with 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.