Neuroblastoma

Neuroblastoma is a type of cancer that arises from immature nerve cells prevalent throughout the body.

The adrenal glands, which have comparable beginnings to nerve cells and reside atop the kidneys, are where neuroblastoma most usually originates. Neuroblastoma can also grow in other parts of the abdomen, such as the chest, neck, and around the spine, where there are clusters of nerve cells.

Neuroblastoma is most frequent in children aged 5 and under, while it can also afflict older children. Some types of neuroblastoma will go away on their own, while others will require numerous treatments. The neuroblastoma treatment options for your child will be determined by a number of factors.

Signs and symptoms of neuroblastoma

Signs and symptoms of neuroblastoma vary depending on what part of the body is affected.

Neuroblastoma in the abdomen — the most common form — may cause signs and symptoms such as:

• Abdominal pain
• A mass under the skin that isn’t tender when touched
• Changes in bowel habits, such as diarrhea or constipation

Neuroblastoma in the chest may cause signs and symptoms such as:

• Wheezing
• Chest pain
• Changes to the eyes, including drooping eyelids and unequal pupil size

Other signs and symptoms that may indicate neuroblastoma include:

• Lumps of tissue under the skin
• Eyeballs that seem to protrude from the sockets (proptosis)
• Dark circles, similar to bruises, around the eyes
• Back pain
• Fever
• Unexplained weight loss
• Bone pain

Causes of neuroblastoma

In general, cancer begins with a genetic mutation that allows normal, healthy cells to continue growing despite the fact that normal cells respond to signals to halt. Cancer cells proliferate and reproduce uncontrollably. The aberrant cells that are collecting form a bulk (tumor).

Neuroblastoma develops with neuroblasts, which are immature nerve cells produced by a foetus as part of its development.

Neuroblasts mature into nerve cells and fibres, as well as the cells that make up the adrenal glands, as the foetus grows older. Although a small number of immature neuroblasts can be discovered in infants, most neuroblasts develop by birth. These neuroblasts mature or die in the majority of cases. Others, on the other hand, develop a tumour called a neuroblastoma. 

The cause of the initial genetic mutation that leads to neuroblastoma is unknown.

Causes

Children with a family history of neuroblastoma may be more likely to develop the disease. Yet, familial neuroblastoma is thought to comprise a very small number of neuroblastoma cases. In most cases of neuroblastoma, a cause is never identified.

Complications

Complications of neuroblastoma may include:

• Spread of the cancer (metastasis). Neuroblastoma may spread (metastasize) to other parts of the body, such as the lymph nodes, bone marrow, liver, skin and bones.
• Spinal cord compression. Tumors may grow and press on the spinal cord, causing spinal cord compression. Spinal cord compression may cause pain and paralysis.
• Signs and symptoms caused by tumor secretions. Neuroblastoma cells may secrete certain chemicals that irritate other normal tissues, causing signs and symptoms called paraneoplastic syndromes. One paraneoplastic syndrome that occurs rarely in people with neuroblastoma causes rapid eye movements and difficulty with coordination. Another rare syndrome causes abdominal swelling and diarrhea.

Diagnosis of neuroblastoma

Tests and procedures used to diagnose neuroblastoma include:

• Physical exam. Your child’s doctor conducts a physical exam to check out any signs and symptoms. The doctor will ask you questions about your child’s habits and behaviors.
• Urine and blood tests. These may indicate the cause of any signs and symptoms your child is experiencing. Urine tests may be used to check for high levels of certain chemicals that result from the neuroblastoma cells producing excess catecholamines.
• Imaging tests. Imaging tests may reveal a mass that can indicate a tumor. Imaging tests may include an X-ray, ultrasound, computerized tomography (CT) scan, metaiodobenzylguanidine (MIBG) scan and magnetic resonance imaging (MRI), among others.
• Removing a sample of tissue for testing. If a mass is found, your child’s doctor may want to remove a sample of the tissue for laboratory testing (biopsy). Specialized tests on the tissue sample can reveal what types of cells are involved in the tumor and specific genetic characteristics of the cancer cells. This information helps your child’s doctor devise an individualized treatment plan.
• Removing a sample of bone marrow for testing. Your child may also undergo bone marrow biopsy and bone marrow aspiration procedures to see if neuroblastoma has spread to the bone marrow — the spongy material inside the largest bones where blood cells are formed. In order to remove bone marrow for testing, a needle is inserted into your child’s hipbone or lower back to draw out the marrow.

Staging of neuroblastoma

Following a diagnosis of neuroblastoma, your child’s doctor may request more tests to evaluate the cancer’s extent and if it has spread to other organs, a procedure known as staging. Knowing the cancer’s stage aids the doctor in determining the best course of treatment.

X-rays, bone scans, CT, MRI, and MIBG scans are among the imaging procedures used to stage cancer.

The stages of neuroblastoma are represented by Roman numerals ranging from 0 to IV, with the lowest stages denoting cancer that is localised. By stage IV, the cancer has spread to other parts of the body and is termed progressed.

Treatment of neuroblastoma

Your child’s doctor decides on a treatment plan depending on a number of factors that influence his or her prognosis. The age of your child, the stage of the disease, the type of cells implicated in the cancer, and whether or not there are any chromosome or gene abnormalities are all factors to consider.

This information is used by your child’s doctor to classify the cancer as low, middle, or high risk. The type of neuroblastoma treatment or combination of treatments your child receives is determined by the risk group.

Surgery

Surgeons use scalpels and other surgical tools to remove cancer cells. In children with low-risk neuroblastoma, surgery to remove the tumor may be the only treatment needed.

Whether the tumor can be completely removed depends on its location and its size. Tumors that are attached to nearby vital organs — such as the lungs or the spinal cord — may be too risky to remove.

In intermediate-risk and high-risk neuroblastoma, surgeons may try to remove as much of the tumor as possible. Other treatments, such as chemotherapy and radiation, may then be used to kill remaining cancer cells.

Chemotherapy

Chemotherapy is a treatment that uses chemicals to kill cancer cells. Chemotherapy is a type of treatment that targets fast developing cells in the body, such as cancer cells. Chemotherapy, however, can create adverse effects by damaging healthy cells that develop quickly, such as those in hair follicles and the gastrointestinal tract.

Before surgery, children with intermediate-risk neuroblastoma often receive a combination of chemotherapy medications to increase the odds of removing the entire tumour.

High-dose chemotherapy medications are given to children with high-risk neuroblastoma to reduce the tumour and kill any cancer cells that have spread elsewhere in the body. Chemotherapy is commonly given prior to surgery and bone marrow transplantation.

Bone marrow transplant

Children with high-risk neuroblastoma may be eligible for a bone marrow stem cell transplant (autologous stem cell transplant).

Your child will have a treatment that filters and gathers stem cells from his or her blood before the bone marrow transplant, commonly known as a stem cell transplant. The stem cells are kept in a freezer until they are needed. The remaining cancer cells in your child’s body are then killed with large doses of chemotherapy. Your child’s stem cells will then be infused into his or her body, where they will be able to generate new, healthy blood cells.

Immunotherapy uses drugs that work by signaling your body’s immune system to help fight cancer cells. Children with high-risk neuroblastoma may receive immunotherapy drugs that stimulate the immune system to kill the neuroblastoma cells.

Newer treatments

Doctors are studying a newer form of radiation therapy that may help control high-risk neuroblastoma. The treatment uses a radioactive form of the chemical metaiodobenzylguanidine (MIBG). When injected in to the bloodstream, the MIBG travels to the neuroblastoma cells and releases the radiation.

MIBG therapy is sometimes combined with chemotherapy or bone marrow transplant. After receiving an injection of the radioactive MIBG, your child will need to stay in a special hospital room until the radiation leaves his or her body in the urine. MIBG therapy usually takes a few days.