A neuroblastoma is one of the most common solid tumors in children. We speak of extra-cerebral malignant tumor because it starts in the nervous system but is not localized in the brain. Several treatment options can be considered depending on the case.

Definition of neuroblastoma

A neuroblastoma is a type of cancer. This malignant tumor has the particularity of developing at the level of neuroblasts, which are immature nerve cells of the sympathetic nervous system. The latter constitutes one of the three pillars of the autonomic nervous system which directs the involuntary functions of the organism such as respiration and digestion.

A neuroblastoma can develop in very different areas of the body. However, this type of cancer most often appears in the abdomen at the level of the adrenal glands (located above the kidneys), as well as along the spine. More rarely, it can occur in the neck, thorax or pelvis (small pelvis).

As it grows, a neuroblastoma can cause metastasis. These are secondary cancers: the cells of the primary tumor escape and colonize other tissues and / or organs.

Classification des neuroblastomes

Cancers can be classified according to many parameters. For example, staging helps assess the extent of cancer. In the case of neuroblastoma, two types of staging are used.

The first stage is the most frequently used. It classifies neuroblastomas from stages 1 to 4 and also includes a particular stage 4s. This is a classification by severity, from the least severe to the most severe:

• stages 1 to 3 correspond to localized forms;
• stage 4 designates metastatic forms (migration of cancer cells and colonization of other structures in the body);
• stage 4s is a specific form characterized by metastases in the liver, skin and bone marrow.

The second stage also has 4 stages: L1, L2, M, MS. It not only makes it possible to differentiate localized (L) from metastatic (M) forms, but also to take into account certain surgical risk factors.

Causes du neuroblastome

Like many other types of cancer, neuroblastomas have an origin that is not yet fully established.

To date, it has been observed that the development of a neuroblastoma could be due or favored by various rare diseases:

• type 1 neurofibromatosis, or Recklinghausen’s disease, which is an abnormality in the development of neural tissue;
• Hirschsprung’s disease which is the consequence of an absence of nerve ganglia in the wall of the intestine;
• Ondine syndrome, or congenital central alveolar hypoventilation syndrome, which is characterized by a congenital absence of central control of breathing and diffuse damage to the autonomic nervous system.

In rare cases, neuroblastoma has also been seen in people with:

• Beckwith-Wiedemann syndrome which is characterized by excessive growth and birth defects;
• Di-George syndrome, a birth defect in the chromosomes that usually results in heart defects, facial dysmorphism, developmental delay and immunodeficiency.

Diagnostic du neuroblastome

This type of cancer can be suspected due to certain clinical signs. The diagnosis of neuroblastoma can be confirmed and deepened by:

• a urine test which evaluates the levels of certain metabolites whose excretion increases during a neuroblastoma (eg homovanilic acid (HVA), vanillylmandelic acid (VMA), dopamine);
• imaging of the primary tumor by ultrasound, CT scan or MRI (magnetic resonance imaging);
• MIBG (metaiodobenzylguanidine) scintigraphy, which corresponds to an imaging test in nuclear medicine;
• a biopsy which consists of taking a piece of tissue for analysis, especially if cancer is suspected.

These tests can be used to confirm the diagnosis of a neuroblastoma, to measure its extent and to check for the presence or absence of metastases.

Neuroblastomas most often occur in infants and young children. They represent 10% of childhood cancer cases and 15% of malignant tumors in children under 5 years old. Each year, around 180 new cases are identified in France.

• Asymptomatic: A neuroblastoma can go unnoticed, especially during its early stages. The first symptoms of neuroblastoma are most often seen when the tumor is spreading.
• Localized pain: The development of neuroblastoma is often accompanied by pain in the affected area.
• Local swelling: A lump, lump, or swelling may appear in the affected area.
• Alteration of the general condition: A neuroblastoma disrupts the proper functioning of the nervous system, which can result in loss of appetite, weight loss, slower growth.

To date, three main treatments can be implemented:

• surgery to remove the tumor;
• radiation therapy, which uses radiation to destroy cancer cells;
• chemotherapy, which uses chemicals to limit the growth of cancer cells.

After the treatments mentioned above, a stem cell transplant can be put in place to restore the proper functioning of the body.

Immunotherapy is a new avenue for treating cancer. It could be a complement or an alternative to the treatments mentioned above. Much research is underway. The goal of immunotherapy is to stimulate the body’s immune defenses to fight the development of cancer cells.

The origin of neuroblastomas remains poorly understood to this day. No preventive measure could be identified.

Prevention of complications relies on early diagnosis. It is sometimes possible to identify a neuroblastoma during the antenatal ultrasound. Otherwise, vigilance is essential after birth. Regular medical monitoring of the child is essential.