Neuroblastoma

  • Dense cancerous tumour that originates in the nerve cells of infants and young children.
  • It can start in the nerve tissue near the spine in the neck, chest, abdomen, or pelvis, but it commonly starts in the adrenal glands.
  • The adrenal glands are located on top of both kidneys and produce hormones that help regulate body functions, such as one’s heart rate and blood pressure.
  • Neuroblasts are undeveloped nerve cells found in unborn babies.
  • Normal neuroblasts develop into nerve cells or adrenal medulla cells (cells found in the centre of the adrenal gland).
  • As a result, neuroblast that fail to mature properly can continue to grow, which leads to neuroblastoma.
  • However, babies are occasionally born with small clusters of neuroblasts that eventually mature into nerve cells and do not become cancer.
  • Neuroblastoma most often develops in infants and children younger than five.
  • It can form before the baby is born and can occasionally be identified during a prenatal ultrasound. (Herbst, 2019)

Statistics

  • Each year, an estimate of 800 children between the ages of 0 and 14 are diagnosed with neuroblastoma in the U.S.
  • It is responsible for 6% of all childhood cancers in the U.S.
  • Nearly 90% of neuroblastoma is found in children younger than 5.
  • It is the third most common type of cancer in children, with the average age of diagnosis being between 1 and 2.
  • Neuroblastoma is also the most diagnosed cancer in children younger than 1, however, it is rare in people older than 10.
  • The 5-year survival rate tells us the percentage of children that live at least 5 years post-diagnosis.
  • Percent (%) means how many out of 100.
  • The 5-year survival rate for neuroblastoma is 81%, however, a child’s survival rate depends on many factors, particularly the risk grouping of the tumour.
    • Children with low-risk neuroblastoma experience a 5-year survival rate of higher than 95%;
    • Children with intermediate-risk neuroblastoma experience a 5-year survival rate between 90% to 95%;
    • Children with high-risk neuroblastoma experience a 5-year survival rate of around 40% to 50%.
  • An estimate of 2 out of 3 children with neuroblastoma are diagnosed with the disease after it has spread to the lymph nodes or to other body parts.

(Cancer.Net, 2020)

Signs & Symptoms

The effects of neuroblastoma can vary extensively depending on where the disease had originated and the extent of its spread to other parts of the body. The initial symptoms are often unclear and may consist of irritability, fatigue, loss of appetite, and fever. But due to these early warning signs having a gradual development while also mimicking those of other common childhood illnesses, diagnosis of neuroblastoma can prove to be difficult.

In young children, neuroblastoma is frequently discovered when a parent or doctor notices an unusual lump or mass somewhere in the child’s body – usually in the abdomen, though tumours appearing in the neck, chest, and elsewhere are not uncommon. The most common signs of neuroblastoma are caused by the tumour pressing on nearby tissues as it develops or by the cancer spreading to other areas. These signs are dependent on how much the cancer has grown and where it has spread. For example, a child may have:

  • A swollen stomach, abdominal pain, and decreased appetite (if the tumour is in the abdomen)
  • Bone pain or tenderness, black eyes, bruises, and pale skin (if the cancer has spread to the bones)
  • Weakness, numbness, inability to move a body part, or difficulty walking (if the cancer presses against the spinal cord)
  • Drooping eyelid, unequal pupils, sweating, and red skin, which are signs of nerve damage in the neck known as Horner’s syndrome (if the tumour is in the neck)
  • Difficulty breathing (if the cancer is in the chest)

(Herbst, 2019)

Diagnosis

Tests and procedures used to diagnose neuroblastoma include:

  • Physical exam.Your child’s doctor conducts a physical exam to identify any signs and symptoms. The doctor will ask questions about your child’s habits and behaviours.
  • Urine and blood tests.If your child is experiencing any signs & symptoms, these tests may indicate the cause thereof. Urine tests may be used to identify 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 tumour. Imaging tests may include an X-ray, ultrasound, computerized tomography (CT) scan, metaiodobenzylguanidine (MIBG) scan and magnetic resonance imaging (MRI), to name a few.
  • Removing a sample of tissue for testing.If a mass is identified, your child’s doctor may want to remove a sample of the tissue for laboratory testing, also called a biopsy. Specialised tests on the tissue sample can reveal the types of cells involved in the tumour as well as specific genetic characteristics of the cancer cells. This information allows your child’s doctor to formulate an individualised treatment proposal.
  • Removing a sample of bone marrow for testing.Your child may also undergo bone marrow biopsy and bone marrow aspiration procedures to identify whether neuroblastoma has spread to the bone marrow – a 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 extract the marrow. (Mayo Clinic, 2019)

Risk Factors

“Risk factors” for neuroblastoma is more commonly used to describe the factors that are used to forecast tumour growth patterns and how effective treatment will be.

Neuroblastoma occurs more often in boys than in girls. Thus far, no environmental factors have been identified to increase the risk of developing neuroblastoma. In most cases, it is rare for more than one member of a family to be diagnosed with neuroblastoma.

Researchers have found inherited gene mutations, or changes, that play a role in the development of neuroblastoma for children with a family history of the disease. Other genetic changes, called single-nucleotide polymorphisms (SNPs), may contribute to the development of neuroblastoma in children who do not have prior family history.

Family history and genetic predisposition

An estimation of 1% to 2% of children with neuroblastoma have a family history of the disease. Children with a hereditary probability of neuroblastoma tend to develop the disease, on average, nine to thirteen months earlier than other children with neuroblastoma. In children who have a family history of neuroblastoma, the disease may occur in 2 or more organs. (Cancer.Net, 2018)

Treatment

  • Surgery – usually for tumours that have not spread (localised tumours)
  • Chemotherapy – If the tumour has already spread by the time of diagnosis, or is indicated as being high-risk by the tumour biology result
    • High doses of chemotherapy with stem cell support are often required if the neuroblastoma has spread to numerous body parts
  • A new monoclonal antibody treatment, known as anti-GD2 is currently being tested in high-risk cases, however the side effects are very unpleasant
  • Radiotherapy:
    • external radiotherapy may be administered if the neuroblastoma is high-risk or has spread to numerous body parts
    • internal radiotherapy may be administered at times using radioactive MIBG, which uses higher doses of radioactivity to kill the cancer cells
  • Children with stage 4S disease, for the most part, always get better with very little treatment or even none whatsoever (Herbst, 2019).

References

  1. Cancer.Net. (2018, April). Neuroblastoma – Childhood: Risk Factors.
    Retrieved from Cancer.Net: https://www.cancer.net/cancer-types/neuroblastoma-childhood/risk-factors
  2. Cancer.Net. (2020, January). Neuroblastoma – Childhood: Statistics.
    Retrieved from Cancer.Net: https://www.cancer.net/cancer-types/neuroblastoma-childhood/statistics
  3. Herbst, P. M. (2019, July). Fact Sheet on Childhood Neuroblastoma.
    Retrieved from CANSA: https://cansa.org.za/files/2019/09/Fact-Sheet-on-Childhood-Neuroblastoma-NCR-2014-web-Sept-2019.pdf
  4. Mayo Clinic. (2019, Oct). Neuroblastoma.
    Retrieved from Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/neuroblastoma/diagnosis-treatment/drc-20351022