Medulloblastoma is the most common malignant tumor of posterior cranial fossa (cerebellum) in children, and it is also the second most common among all childhood malignant brain tumors (about 20% of all cases). Medulloblastoma has 2 peaks of incidence – at the age of 3-4 years and 8-10 years, but can occur throughout childhood, and sometimes in young people. Medulloblastoma is a simple neuroectodermal tumor (PNET) in origin.
Medulloblastoma is an aggressive tumor that grows rapidly and spreads to adjacent areas of brain and spinal cord. Most of these tumors are primarily located inside cerebellum near the 4th ventricle of brain.
Medulloblastoma is a serious disease, but with timely diagnosis and correctly chosen treatment tactics, it is completely curable. Establishing such a diagnosis or suspicion of it, it is extremely important to find a highly specialized doctor with experience in managing patients with medulloblastomas. These are the specialists who work in Pediatric Hematology Oncology Department of Tel Aviv Medical Clinic. Thanks to work of a professionals team, we are able to achieve success even in the most difficult cases.
Our specialists are highly qualified and have rich practical experience; most of them have repeatedly trained at the best oncology centers in the world, where they gained invaluable experience working with children and acquired professional communication skills with young patients.
In their work, doctors are guided only by modern clinical recommendations and global treatment protocols. At the same time, we practice a purely individual approach to each clinical situation. Developing a treatment regimen, doctor takes into account both the characteristics of the child and certain characteristics of his neoplasm. This makes it possible to create the most effective personalized treatment regimen for each individual child, which in future only has a positive effect on the long-term prognosis.
Another medulloblastoma treatment advantage at TAMC is the multidisciplinary approach. One patient with a brain tumor is immediately assisted by a whole team of highly specialized doctors: oncologists, neurosurgeons, neurologists, radiation therapists, chemotherapists, rehabilitation specialists, psychologists and other doctors if necessary. Thus, in one medical institution you can receive all the necessary medical procedures, starting from the diagnostic stage, ending with complex treatment and the necessary amount of rehabilitation measures.
Medulloblastoma causes
Unfortunately, the true causes of medulloblastoma development have not been established to date. But there are certain genetic syndromes in which this tumor develops more often. These include:
- Fanconi anemia,
- Turcot syndrome,
- Gorlin syndrome,
- Rubinstein-Taybi syndrome,
- Li-Fraumeni syndrome.
Tumor cells of medulloblastoma have some characteristic genetic features that make it possible to distinguish several types of this neoplasm:
- type WNT,
- type SHH,
- type 3,
- type 4.
The specific molecular subtype of medulloblastoma affects the prognosis of the disease, and this information also helps doctors to create the most effective treatment plan in each specific case, since different types of tumor differ in their sensitivity to certain treatment methods.
Symptoms of medulloblastoma in children
Medulloblastoma clinical manifestations primarily depend on tumor size, its location in brain and child’s age. Most often you can notice the following pathological symptoms:
- constant or frequent headache;
- nausea and vomiting due to headache;
- increased fatigue, inability to concentrate;
- imbalance; change in gait;
- frequent falls;
- dizziness;
- various visual impairments;
- impairment of written language skills;
- backache;
- various motor disorders (paralysis and paresis of limbs);
- dysfunction of pelvic organs.
As the tumor grows in size, it disrupts normal circulation of cerebrospinal fluid and leads to increased intracranial pressure, which causes most of disease symptoms.
Modern diagnostic methods
In of Pediatric Hematology Oncology Department at TAMC, only modern expert-class diagnostic equipment is used, making the diagnostic process surprisingly comfortable and accurate.
Diagnostic program begins with a face-to-face consultation with department’s leading oncologist. Taking a medical history and examining the patient can help us to understand more about symptoms, general health, past illnesses, and risk factors.
Without fail, patient undergoes a thorough examination by the best pediatric neurologist in the department. A neurological examination evaluates various aspects of brain and spinal cord, identifying symptoms and syndromes that help the doctor to realize where exactly the tumor is located.
At the next stage of diagnostics, doctors prescribe modern examinations for neuroimaging – CT, MSCT, MRI. They allow us to accurately determine tumor location, its size and distribution. After surgery to remove a tumor, it is mandatory to perform a biopsy and pathohistological examination of tissue samples. This allows us to confirm the diagnosis, as well as determine the molecular subtype of tumor. Pathological examination can help in predicting the outcome of treatment. This information also helps specialists to categorize patients into risk groups and prescribe appropriate comprehensive treatment.
After biopsy, we send all materials for revision to the best pathohistological laboratories in Israel, where they are examined by a qualified specialist. Thanks to such checks, we are absolutely sure of diagnosis correctness and the further chosen treatment tactics. Also, after biopsy, innovative molecular genetic tests are carried out to identify the characteristics of tumor cells, which makes it possible to select the most effective treatment regimen and innovative targeted drugs. One such test is Foundation One Comprehensive Genomic Tumor Profiling.
Prognosis for medulloblastoma
The five-year survival rate of children with medulloblastoma in the absence of tumor spread to neighboring areas is 70-80%. For patients with high-risk tumors, the 5-year survival rate is 60-65%.
Factors that influence on prognosis for medulloblastoma development in a child:
- histological type and molecular subtype of tumor;
- neoplasm is localized or has already spread to neighboring areas of nervous tissue;
- if complete surgical removal of tumor ispossible;
- child’s age at the time of diagnosis;
- this is a primary tumor or a recurrence of the disease.
Medulloblastoma modern treatment
Children with brain tumors such as medulloblastoma should only be treated by doctors from clinics that have a specialized department of pediatric oncology and neurosurgery. Tel Aviv Medical Clinic is just such a medical center. We employ highly qualified specialists who are proficient in modern comprehensive treatment programs. The goal of any therapy program is to treat the child as sparingly as possible and at the same time reduce the risks of possible side complications during treatment and long-term consequences after its completion.
Medulloblastoma treatment includes surgery to remove the tumor, radiation therapy to brain and spine (except for infants and young children), chemotherapy, and sometimes experimental therapies in clinical trials.
Neurosurgical interventions is the main type of treatment for medulloblastoma. Its goal is the most complete removal of tumor conglomerate, and if this is not possible, resection of accessible part of tumor.
Modern neurosurgery in Israel has achieved incredible development, so patients with central nervous system tumors have access to innovative and effective surgical interventions on brain, including:
- stereotactic radiosurgery, for example, using gamma knife installation, cyber knife, X-knife and nano knife, when surgery is performed precisely without a single incision with a scalpel;
- cryosurgery is a neurosurgical procedure that uses liquid nitrogen-cooled probes that are inserted directly into the tumor to destroy it while completely sparing healthy surrounding tissue.
Also, neurosurgical intervention can be carried out by craniotomy – this is a certain part of skull bones removal so that the surgeon can gain access to the part of brain that interests him and carry out all the necessary manipulations. With the help of modern neuroimaging equipment (intraoperative MRI), surgeon is able to obtain in real time an accurate map of brain zones location in a particular patient. This ensures delicate removal of tumor conglomerate and preservation of functionally important areas of brain.
Sometimes neurosurgical interventions are performed in the awake mode, when patient is not put under general anesthesia and remains fully conscious. This approach allows us to control important brain functions during surgery and avoid their disruption.
The next step after surgical treatment is radiation therapy. Due to the high risk of severe long-term consequences developing, radiation is not used in children under 3 years of age. The intensity of radiation and its type depend on disease stage.
Proton radiation therapy has been shown to be particularly effective. This type of radiation allows us to achieve the maximum dose of radiation in tumor area, while the surrounding healthy tissues receive a minimum amount of ionizing radiation. TAMC has the most modern facilities for proton beam therapy, which are not only effective, but also safe for application in pediatric practice.
Chemotherapy is also included in t medulloblastoma he treatment. It is especially relevant for young children, who are contraindicated for radiation therapy. In our department chemotherapy doctors will calculate the optimal number of sessions and dosage of drugs, depending on the child’s age, risk degree of pathology and its stage.
Children with recurrent medulloblastoma or an initially resistant tumor to standard treatment protocols after surgery and radiation may be offered treatment in clinical trials. The latter include the application of innovative immunotherapy drugs, including targeted therapy. Among targeted drugs today, signal transduction inhibitors (Vismodegib) are used to treat medulloblastoma; they block molecular signals inside malignant cells, which leads to their irreversible death.
Autologous hematopoietic stem cell transplantation is also used in treatment of patients with relapsed medulloblastoma. The procedure is carried out after high-dose chemotherapy and allows us to replace damaged bone marrow cells with healthy ones (these are the child’s own cells, prepared before chemotherapy start).
In each individual case, the decision on a combination of treatment methods for medulloblastoma is made jointly by a multidisciplinary team of specialists from Pediatric Hematology Oncology Department of TAMS. Thanks to this approach, we are able to achieve excellent survival rates among patients with this cancer, even in the most difficult cases.
