neuroblastoma

Neuroblastoma: description

Neuroblastoma is the second most common childhood cancer in Germany. It is a tumor of the so-called sympathetic nervous system, which controls involuntary tasks in the body. For example, it controls cardiovascular function, bladder and intestinal activity and energy metabolism. The sympathetic nervous system ensures that our body functions optimally in stressful situations. Since it occurs in many parts of the body, a neuroblastoma can also form in very different places:

In about half of the cases there is a neuroblastoma in the adrenal medulla. In addition, it often occurs in the nerve plexuses right and left of the spine, the limiting strand – most often at the level of the stomach, but sometimes at the level of the neck, chest or pelvis.

In the brain, on the other hand, neuroblastoma occurs only when cells separate from the original tumor, enter the brain and form secondary tumors (metastases) there. But that rarely happens. Also, settlements in the lungs are not very common. Neuroblastoma metastases are typically found in bone marrow, bone, lymph nodes, liver or skin. About half of all neuroblastomas have already been diagnosed.

Depending on the severity, neuroblastoma diseases are divided into four disease states. It takes into account how large the tumor is, whether it has spread and whether lymph nodes are affected. It is also estimated to what extent the tumor can be surgically removed. Both the therapy and the prognosis of the disease depend on this classification.

Neuroblastoma: frequency

The neuroblastoma is formed from immature (embryonic) cells. Therefore, the disease occurs primarily in early childhood. About one in every 100,000 children gets neuroblastoma every year. About 40 percent of them fall ill in their first year of life. 90 percent of affected children are younger than six years old. With age, the likelihood of developing a neuroblastoma decreases. Nevertheless, older children, adolescents and adults can get sick. Overall, boys are slightly more affected than girls.

Neuroblastoma: symptoms

Neuroblastoma does not always cause symptoms. Often, therefore, the tumor is discovered only by accident, for example as part of a routine examination at the pediatrician. If a neuroblastoma causes symptoms, the cancer is already well advanced in many cases. Discomfort then arises, for example, in that the tumor narrows surrounding structures or impairs organ functions through metastases. Since a neuroblastoma can grow in many places in the body, also the symptoms vary.

A tumor in the ribcage can cause distress. In the abdomen, a neuroblastoma can hinder the flow of urine and, in extreme cases, damage the kidneys (hydronephrosis). If the neuroblastoma grows along the marginal cord along the spine, it can displace the nerve roots and cause paralysis. A tumor in the neck area can lead to the so-called Horner syndrome. An eyelid hangs down, the eyeball falls back and the pupil narrows. Almost every fifth child with a neuroblastoma develops a Horner syndrome.

Patients with an already metastatic neuroblastoma often suffer from general symptoms such as pain, an impaired general condition, fever or paleness. Metastases in the eyeball sometimes cause bruising on the eye (monocular or glandular hematoma). In less than two percent of those affected, a neuroblastoma is manifested by a so-called opio-myoclonus syndrome. The patients involuntarily twitch their eyes, arms and legs.

Also listlessness or increased sweating may be due to a neuroblastoma. If the tumor is affected by lymph nodes, it is sometimes possible to palpate small nodules or swellings in the abdomen or neck. Infants often have a distended stomach, constipation, diarrhea, nausea or vomiting. Sometimes the blood pressure also increases due to the tumor.

Neuroblastoma: causes and risk factors

Neuroblastoma develops when immature cells of the sympathetic nervous system change malignantly. Maybe that happens before the birth. However, there are no indications that certain events during pregnancy increase the risk of neuroblastoma. Although this tumor is not a hereditary disease, experience reports for the neuroblastoma indicate that in very rare cases the disease is familial.

Neuroblastoma: examinations and diagnosis

If a neuroblastoma is suspected, the doctor first inquires about the symptoms (type, strength and time of onset) as well as other health problems (collection of the medical history = anamnesis).

Physical examination and ultrasound

He then performs a physical examination. Ultrasound examination (sonography) can also be helpful: the doctor can use it to check whether there is a mass (due to tumor growth) in the patient’s abdominal area or neck area.

laboratory tests

Also important are laboratory tests: Blood and urine samples are searched for tumor markers – substances that may be present in increased concentrations in the case of cancer. Tumor markers in neuroblastoma are degradation products of certain hormones (catecholamines) and the enzyme NSE (neuron-specific enolase). In addition, blood values ​​are examined, which may indicate an increased cell metabolism and thus a malignant tumor.

MRI, CT & Co.

When these first examinations reveal the diagnosis of neuroblastoma, the patient is usually referred to a cancer center (oncology). This is followed by further investigations to determine the exact size and location of the tumor and to detect any metastases. Magnetic resonance tomography (MRI), computed tomography (CT), bone marrow and tissue examinations as well as so-called scintigraphy are of particular help here.

scintigraphy

Scintigraphy is a nuclear medical examination in which a radioactively labeled substance is injected via a vein into the bloodstream and then accumulates in certain organs. These can then be visualized because the radiation emitted by the radioactive substance can be detected and visualized with a special camera.

To mark and detect neuroblastoma cells, the radioactively labeled substance MIBG (methyl iodobenzylguanidine) is used. Almost all tumors accumulate this substance (MIBG-positive neuroblastomas), but only a few do not (MIBG-negative neuroblastomas).

Bone marrow examination

Bone marrow cancer cells are easily overlooked in scintigraphy if their numbers are low. Therefore, a bone marrow examination is performed in some patients. Under local anesthesia, the doctor used a long hollow needle to extract a small amount of bone marrow from the bone. Often this investigation is carried out in several places. The tissue obtained is examined under the microscope for cancer cells.

Other tests

For later therapy it is also sometimes necessary to check the heart, hearing and kidney function.

Neuroblastoma: treatment

A neuroblastoma can be operated on, irradiated or treated with special anticancer drugs (chemotherapeutic agents). Often, these three methods are combined. In addition, some patients are receiving MIBG therapy, stem cell transplantation, and retinoic acid medications. Which treatment is recommended in a particular case depends mainly on the stage of the disease and the age of the patient.

Neuroblastoma: surgery

As part of an operation, the surgeon tries to remove the neuroblastoma as completely as possible without injuring other structures. If the tumor is very large or unfavorable, it is sometimes reduced with chemotherapy before surgery (neoadjuvant chemotherapy). Although the tumor can not be completely removed, surgery is often followed by chemotherapy or radiation (adjuvant therapy).

Neuroblastoma: chemotherapy

If a neuroblastoma can not be completely removed or there are already metastases, chemotherapy is usually performed. In order to capture as many malignant cells as possible, we combine various chemotherapeutic agents. They are administered via a vein at regular intervals.

Neuroblastoma: stem cell transplantation

If a neuroblastoma attacks the bone marrow, stem cell transplantation may become necessary. For this, the patient is first taken from the bone marrow healthy stem cells and stored safely. Then there is a high-dose chemo that is supposed to destroy all malignant cells. This is also the basis of the remaining healthy cells in the bone marrow. To allow blood to be re-formed in the bone marrow, the patient then receives back his stem cells taken before chemotherapy via an infusion. They should settle again in the bone marrow and form blood cells. Throughout treatment, patients are very susceptible to pathogens. Therefore, special protective measures must be observed.

Neuroblastoma: MIBG therapy

The radiolabelled substance MIBG used in scintigraphy (see above) can also be used to treat neuroblastoma patients. It is chosen so high a radioactive dose that the neuroblastoma cells that attach the MIBG, thereby destroyed. For example, MIBG therapy may be used if malignant tumor cells are still present in the body after chemotherapy.

Neuroblastoma: disease course and prognosis

In the case of neuroblastoma, the course of the disease mainly depends on the age of the patients and the stage of the disease. Young patients and those in early disease stages therefore have a better prognosis. About 75 percent of neuroblastoma patients survive the next 15 years. In low-risk patients, the survival rate is over 95 percent. Of the high-risk patients, however, only 30 to 40 percent live five years after the diagnosis.

Even if the tumor could be completely removed, it returns in some patients after a certain time (recurrence). Most recurrences occur in the first years after therapy. For this reason, regular check-ups should always be carried out, especially during the first ten years. Physical examinations, laboratory examinations and imaging procedures can be used early on neuroblastoma discover.