What is Neuroblastoma?
Neuroblastoma is an extracranial solid malignancy that develops in the adrenal gland and is prevalent among infants and young children. It is a malignant tumor that usually develops in any of the adrenal glands but can also develop in the nerve tissues of the chest, neck, abdomen and the pelvis. Neuroblastoma on the other hand is a rare type of cancer that usually develops before the child is born and remains unrecognized until the tumor has reached a significant size and has affected the body.
Neuroblastoma arises from the nerve tissues of any of the adrenal glands. It is a rare type of cancer that is usually diagnosed in children before they reach the age of one year while it rarely affects children aged 10 years old and above. The adrenal glands function in producing a hormone that is vital in controlling the heart rate, the levels of sugar in the blood, blood pressure and is also an important factor in helping the body in reacting to stress.
Staging the cancer is an important factor in determining the type of treatment necessary for the patient. Staging is the process of determining the extent of the cancer or the spread of cancer to other parts of the body. The stage of cancer in Neuroblastoma is based on the results of imaging tests, physical exams and the biopsy of the tumor. The stage of Neuroblastoma is among the components in factors that determines the risk group of the child.
The stage of Neuroblastoma can be determined with bone marrow aspiration and biopsy to screen for any signs of cancer. A lymph node biopsy is also an integral in recognizing cancer cells while the biopsy can be done either with excision biopsy or core biopsy or may also be done with a needle biopsy. Imaging tests such as MRI, CT scan, chest X-ray, ultrasound and radionuclide scan are all important in identifying the stage of Neuroblastoma.
Stage I of Neuroblastoma is characterized with a cancer cell situated in one area only and all the tumor that can be identified can be completely removed with surgery and the lymph nodes outside the tumor remain free from cancer.
Stage II Neuroblastoma is divided into two:
- Stage IIA is defined by tumor located in one area only while the other tumors that can be seen cannot be completely removed in surgery. The cancer cell has not spread to the lymph nodes in this stage.
- Stage IIB is characterized by cancer located in only one area while the visible tumors may or may not be removed completely with surgery. Lymph nodes near the main tumor contains Neuroblastoma cells but has not spread to distant tissues of the body or other side of the body.
Stage III of Neuroblastoma has no significant spread of cancer to other parts of the body while the tumor can be identified in only one part of the body with spreads on lymph nodes in other part of the body. The tumor in this stage may also be located in the midline of the body and the tumor has spread to lymph nodes on both sides of the body. The tumor also regardless of its location cannot be completely removed with surgery.
Stage IV of Neuroblastoma is divided into 4 and 4s:
- Stage IV of Neuroblastoma has cancer that has spread to distant lymph nodes and distant tissues such as in the bone, bone marrow, liver, skin and other distant organs and parts of the body.
- Stage 4s is also termed as special Neuroblastoma and the cancer is located only in one area and the cancer has spread to the lymph nodes on the same site. The Neuroblastoma has also reached the skin, the liver and the bone marrow although a little portion of the bone marrow may have the cancerous cells. No spread in bone and bone marrow on the other hand is evident during imaging tests. Stage 4s is considered in children below the age of 1 year old. The tumor however including all evident tumors may be removed completely with surgery.
Neuroblastoma initially develops before the child is born and is only identified later or when the size of the tumor has enlarged. The increase in size of the tumor causes the symptoms which may be due to the tumor pressing on the adjacent tissues and the spread of cancer to other parts of the body. The initial onset of symptoms is indistinguishable which may only imitate similar childhood illnesses.
The symptoms of Neuroblastoma on the other hand vary depending on the site of the tumor growth. The symptoms also depend on the size of the tumor growth and the presence of spread to other parts of the body.
The manifestation of symptoms caused by the main tumor includes the following:
- Palpable mass or lump in the abdomen
- Abdominal swelling
- Loss of appetite
- Loss of weight
- Abdominal pain or the feeling of fullness
- Problems with bladder and bowel movements
- Swelling in the upper chest, face, neck and arms if the tumor is pressing on the superior vena cava
- Drooping eyelid
- Inability to feel or move the arms or the legs
The manifestation of Neuroblastoma that has spread has signs and symptoms such as the following:
- Palpable lump under the skin such as in the neck, armpit and groin
- Pain in the bone causing the child to limp or may even refuse to walk
- Weakness in the arms or in the legs
- Paralysis of the arms or the legs
- Bluish discoloration or bruising around the eyes
- Excessive bleeding from small cuts
- Recurrent bouts of infection
Neuroblasts are immature nerve cells that are generally formed during the fetal stage and which is part of the development process. Neuroblastoma occurs when the neuroblasts failed to develop into nerve cells when these neuroblasts grow and divide uncontrollably. The precise cause of this abnormal growth remains vague although most researches have implicated genetic deficit in the incidence.
The treatment of Neuroblastoma depends on the stage by the time the child was diagnosed, the age of the child, the type of cancer cells and the presence of spread. The stage of Neuroblastoma determines the plan of treatment that can be applied.
The risk group is also another factor in determining the treatment plan for the child and Neuroblastoma is composed of three risk groups.
- Low risk can be cured with the surgery alone and may resolve without treatment
- Intermediate risk is treated with a chemotherapy and surgery
- High risk is treated with surgery, chemotherapy, radiation therapy, and stem cell transplantation although this risk group is rather difficult to resolve
The survival rate in Neuroblastoma depends on which risk group the child belongs. The 5 year survival rate is the percentage of the patients who survived the disease in at least five years from the time of diagnosis.
- Low risk has the highest percentage of survival rate which accounts for about 95%
- Intermediate risk accounts for around 80% to 90% of survival rates
- High risk has a 5 year survival rate of around 30% to 50%
The prognosis or the outlook for Neuroblastoma depends on the stage by the time the disease was diagnosed and the risk group the patient belongs. High risk group has about 20% to 50% of cases that do not effectively respond to intensive or high dose chemotherapy. Both the low risk and intermediate risk group have long term survival. Hearing loss on the other hand is the drawback in patients belonging to intermediate risk and high risk.