What is neuroblastoma?
Neuroblastoma is cancer that changes from undeveloped nerve cells that are found in various areas of the body.
Neuroblastoma most often arises in and around the adrenal glands, which have origins similar to nerve cells and are located above the kidneys. However, neuroblastoma can also develop in other areas of the abdomen and in the chest, neck, and near the spine, where clusters of nerve cells exist.
Neuroblastoma most often affects children 5 years and younger, although it can rarely occur in older children. Some forms of neuroblastoma go gone on their own, while others may require numerous treatments. Your child’s neuroblastoma treatment options will rest on several factors.
Symptoms of neuroblastoma
The signs and symptoms of neuroblastoma vary depending on the part of the body affected. Neuroblastoma in the abdomen, the most common form, can cause signs and symptoms such as:
• Abdominal pain
• A mass under the skin that is not tender to touch.
• Variations in bowel habits, such as diarrhoea or constipation
NB is the chest can cause signs and symptoms such as:
• Chest pain
• Eye changes, including drooping eyelids and uneven-sized pupils
Other signs and symptoms that may specify NB include:
• Lumps of tissue under the skin
• Eyeballs that appear to protrude from the orbits (proptosis)
• Dark, bruise-like circles around the eyes
• Back pain
• Unexplained weight loss
Causes of neuroblastoma
In general, cancer begins with a gene mutation that allows normal healthy cells to continue growing without responding to the signals to stop, which normal cells do. Cancer cells grow and multiply out of control. The abnormal cells build up to form a mass (tumor). It begins in neuroblasts – immature nerve cells that the fetus produces as part of its development process.
As the fetus matures, neuroblasts eventually develop into nerve cells and fibres and into the cells that make up the adrenal glands. Most neuroblasts mature at birth, although a small number of immature neuroblasts can be found in newborns. In most cases, these neuroblasts mature or disappear. Others, however, form a tumor: neuroblastoma. It is not clear what causes the initial genetic mutation that leads to this disease.
Children with a family history of NB may be additional likely to mature the disease. However, familial neuroblastoma is believed to comprise a very small number of NB cases. In most cases of neuroblastoma, a source is never identified.
Complications of neuroblastoma
Neuroblastoma complications can include:
- Spread of cancer (metastasis): Neuroblastoma can spread (metastasize) to other parts of the body, such as the lymph nodes, bone marrow, liver, skin, and bones.
- Compression of the spinal cord: Tumors can grow and press on the spinal cord, causing compression of the spinal cord. The compression of the spinal cord can cause pain and paralysis.
- Signs and symptoms caused by tumorous secretions: Neuroblastoma cells can secrete certain chemicals that irritate other normal tissues, causing signs and symptoms called paraneoplastic syndromes. A paraneoplastic syndrome that occurs rarely in people with neuroblastoma causes rapid eye movements and difficulty with coordination. Another rare syndrome causes abdominal bloating and diarrhoea.
Diagnosis of neuroblastoma
The tests and procedures used to diagnose neuroblastoma include:
- Physical exam: Your child’s doctor performs a physical exam to check for any signs and symptoms. The doctor will ask you questions about your child’s habits and behaviours.
- Blood and urine tests: These can indicate the cause of any signs and symptoms your child is experiencing. Urinalysis can be used to detect high levels of certain chemicals that result from neuroblastoma cells producing excess catecholamines.
- Imaging tests: Imaging tests can reveal a mass that may indicate a tumor. Imaging tests may include X-rays, ultrasound, computed tomography (CT), metaiodoben zylguanidine (MIBG) scan, and magnetic resonance imaging (MRI), among others.
- Extraction of a tissue sample for analysis: If a mass is found, your child’s doctor may want to remove a sample of the tissue for laboratory tests (biopsy). Specialized tests on the tissue sample can reveal what types of cells are involved in the tumor and the specific genetic characteristics of the cancer cells. This information helps your child’s doctor design an individualized treatment plan.
- Extraction of a bone marrow sample for analysis: Your child may also have a bone marrow biopsy and bone marrow aspiration procedures to see if the neuroblastoma has spread to the bone marrow, the spongy material within the larger bones where blood cells form. In order to collect the bone marrow for analysis, a needle is inserted into your child’s hip bone or lower back to remove the marrow.
Once neuroblastoma is diagnosed, your child’s doctor may order more tests to find out the amount of cancer and whether it has spread to distant organs, a process called staging. Knowing the stage of cancer helps the doctor decide which treatment is the most appropriate.
Imaging tests used to know the stage of cancer include X-rays, bone scans and CT scans, MRIs, and MIBGs, among others.
The periods of neuroblastoma are indicated by Roman numerals ranging from 0 to IV, and the lower stages indicate cancer that is limited to one area. In stage IV, cancer is considered advanced and has spread to other areas of the body.
Treatment of neuroblastoma
Your child’s doctor selects a treatment plan based on several factors that affect your child’s prognosis. Factors contain your child’s age, the stage of cancer, the kind of cells involved in cancer, and whether there are any abnormalities in the chromosomes and genes.
Your child’s doctor uses this information to classify cancer as low risk, intermediate-risk, or high risk. The treatment or combination of treatments your child receives for NB depends on the risk category.
Surgeons use scalpels and other surgical instruments to remove cancer cells. In children with low-risk neuroblastoma, surgery to eliminate the tumor may be the only treatment wanted.
The complete removal of the tumor depends on its location and size. Tumors that are attached to nearby vital organs, such as the lungs or spinal cord, can be too risky to remove.
In intermediate-risk and high-risk neuroblastoma, surgeons may attempt to remove as much of the tumor as possible. Then other treatments, such as chemotherapy and radiation, can be used to kill the remaining cancer cells.
Chemotherapy uses chemicals to kill cancer cells. Chemotherapy targets quickly growing cells in the body, as well as cancer cells. Unfortunately, chemotherapy also damages rapidly-growing healthy cells, such as cells in the hair follicles and the gastrointestinal system, which can cause side effects.
Children with intermediate-risk neuroblastoma frequently receive a grouping of chemotherapy drugs before surgery to improve the chances that the entire tumor can be removed.
Children with high-risk neuroblastoma, typically receive high doses of chemotherapy drugs to shrink the tumor and end any cancer cells that have spread to other parts of the body. Chemotherapy is generally used before surgery and before bone marrow transplantation.
Radiation therapy usages high-energy rays, such as X-rays, to kill cancer cells. Children with low- or intermediate-risk neuroblastoma may receive radiation therapy if surgery and chemotherapy have not been helpful. Children with high-risk neuroblastoma may receive radiation therapy after chemotherapy and surgery to prevent cancer recurrence.
Radiation therapy mainly affects the area where it is targeted, but radiation can damage some healthy cells. The side effects your child experiences depend on where the radiation is directed and how much radiation is given.
Bone marrow transplant
Children with high-risk neuroblastoma may receive a transplant with stem cells taken from the bone marrow (autologous stem cell transplantation).
Before the bone marrow transplant, also known as a stem cell transplant, your child undergoes a procedure that filters and collects stem cells from her blood. Stem cells are stored for later use. Then, high doses of chemotherapy are used to kill the remaining cancer cells in your child’s body. Your child’s stem cells are then vaccinated into your child’s body, where they can form new, healthy blood cells.
Immunotherapy uses drugs that work by sending signals to 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 destroy neuroblastoma cells.
Doctors are studying a newer form of radiation therapy that can help control high-risk neuroblastoma. The treatment usages a radioactive form of the chemical metaiodobenzylguanidine (MIBG). When injected into the bloodstream, MIBG travels to neuroblastoma cells and releases radiation.
MIBG therapy is sometimes combined with chemotherapy or bone marrow transplantation. After receiving an injection of the radioactive MIBG, your child will need to stay in a special hospital room until the radiation leaves her body in the urine. MIBG therapy usually takes a few days.
The risk of many cancers in adults can be reduced with certain lifestyle changes (such as maintaining a healthy weight or quitting smoking), but at this time there are no known ways to prevent most cancers in children.
The only recognized risk factors for NB (age and heredity) cannot be changed. At this time, there are no known environmental or lifestyle causes of neuroblastomas.
Some studies suggest that getting mothers to take prenatal multivitamins or folic acid could reduce the risk of NB, but more research is needed to confirm this. Getting care from a doctor during pregnancy is always important to the health of your baby.
If there is a history of NB in your family, you may want to speak with a genetic counsellor about the risks of your children developing the disease. However, it is important to remember that familial neuroblastoma is very rare.