Neuroblastoma

The malignancy neuroblastoma is a condition that affects the nerve cells of the body. Based on several studies, it is found that this disease is the 3rd most common type of cancer found in children [1, 2].

What is Neuroblastoma?

From the name itself, neuroblastoma is the tumor formation involving the nerve cells of the body. These tumors usually originate in the nerve cells of the adrenal gland or in the chest area. Neuroblasts have the same characteristics as immature nerve cells that are found in fetus.

Image 1 – Nerve Innervation of different viscera

This type of tumor may start developing since early childhood but will not be detected unless it has started causing symptoms. There are cases where the tumor develops in the fetus while still inside the womb. Oftentimes, the neuroblastoma have already metastasized to other organs such as the liver, lymph nodes, bone marrow and bones when it is diagnosed [1, 3, 4].

Staging

The stage of the malignancy indicates the extent of the disease and if it has metastasized or spread to other organs. Neuroblastoma has 4 distinct stages and the further the stage, the lower is its survival rate [4, 5].

Stage I

The tumor is still confined to its original location and the area surrounding the tumor is still free from cancer cells [4, 5].

Stage II

The cancer is still on the originating organ but there are neuroblastoma cells that are found on the nearby lymph nodes. There are no traces of cancerous cells on other lymph nodes of the body [4, 5].

Stage III

The malignancy have not spread to distant parts of the body but it may be extending to the opposite side of the body. If the tumor is in the center of the body, the tumor may be extending to either sides of the body [4, 5].

Stage IV

Neuroblastoma had already spread to distant parts of the body but does not qualify for the stage IVS classification [4, 5].

Figure 2 – Neuroblastoma Stage 1 Vs Stage 4

Stage IVS

This special classification of neuroblastoma applies to children who are less than 1 year of age. It may have spread to the bone marrow but less than 10% of the marrow cells are cancerous [4, 5].

Causes

Appearance of cancerous cells may be associated with genetic errors. These mutation makes the cells to continue dividing and unable to respond to the signals to stop growing. The neuroblasts will continue to grow and develop into a tumor. Further research are required to identify which genetic errors directly cause neuroblastoma [1, 3].

Risk Factors

The risk factors for the development of neuroblastoma in adults may include cigarette smoking, physical activity, body weight and diet. Risk factors play a small role in the formation of neuroblastoma in children. Around 1% of all cases have a parent who had the same condition. The cause of all other neuroblastoma cases are unknown [1, 4].

Signs and Symptoms

The signs and symptoms that will be experienced by the patient will depend on the organ that is affected. Some of the early symptoms that can be felt by the patient includes easy fatigability, fever, loss of appetite and irritability. These symptoms are similar to other illness which makes early diagnosis of neuroblastoma to be difficult. If the mass have developed in the abdomen, there may be a lump that can be felt. Involvement of the bone may cause bone pain, paleness of the skin and appearance of bruises. If the spinal cord is affected, the patient may experience difficulty in movement and numbness in the extremities [3, 6].

Diagnosis

Health history and physical examination

The history would include previous illness and familial history of neuroblastoma. The physical examination will include assessment of the patient’s general health to identify any symptoms that can be present [2, 3].

Imaging tests

Imaging tests such as CT scan and MRI scan may be requested to visualize the tumor of the patient. This test is crucial in establishing the stage of the patient’s condition [2, 3].

Neurological exam

This tests involves some questions and tests to assess the function of the nerve. The result of this test may give the physician an idea of the effect of the neuroblastoma to the body [2, 3].

Treatment

The treatment that is required depends on the stage of the patient’s condition. Those who have stage I neuroblastoma may undergo a surgical procedure alone or a combination of surgery and chemotherapy. Patients who are diagnosed with stage II and stage III may need to undergo radiotherapy aside from the aforementioned treatments. Radiotherapy is performed to eliminate the cancer cells which may remain after the surgical procedure [1, 3].

Stage IV neuroblastoma treatment has 4 distinct parts. The goal of the first phase or induction phase is to reduce the amount of cancer cells in the body and this may be achieved with chemotherapy. The next stage, which is the local control phase, involves a surgical procedure to remove the tumor.

Radiotherapy

Radiotherapy will follow the procedure to ensure that no cancer cells will remain in the body. The third stage called consolidation treatment includes a high dose chemotherapy with stem cell transplant. After this phase, there will be a small possibility some neuroblastoma are left and may turn into a tumor.

Maintenance Treatment

The physician may advise for the patient to undergo a maintenance treatment which will lower the risk of the tumor coming back. Those who are in this phase of treatment may need to take a drug called isotretinoin and undergo immunotherapy to boost the body’s immune system. Several researches are ongoing to identify the best maintenance treatment for neuroblastoma [ 1, 3].

Prognosis and Survival Rate

The past 35 years have seen a great improvement in the 5-year survival rate of those with neuroblastoma. The rate have climbed from 86% to 95% for children less than 1 year old. Those who are between 1-14 years old used to have 34% survival rate in 1975 but became 68% in 2010. Almost a quarter of individuals with neuroblastoma have already a metastasis when they are diagnosed with the malignancy.Factors that have affected the treatment outcome of these patients include involvement of the regional lymph node, histology of the tumor and the response of the patient to the treatment and age of the patient upon diagnosis.

References

• Cancer Research UK. (2015, June 30). Neuroblastoma. Retrieved from Cancer Research UK: http://www.cancerresearchuk.org/about-cancer/cancers-in-general/cancer-questions/neuroblastoma#UEti5c5TRR2EgQbI.97
• Cunha, J. P. (2007, December 19). Neuroblastoma. Retrieved from MedicineNet.com: http://www.medicinenet.com/neuroblastoma/page6.htm
• Mayo Clinic Staff. (2015, December 4). Neuroblastoma. Retrieved from Mayo Clinic: http://www.mayoclinic.org/diseases-conditions/neuroblastoma/home/ovc-20164436
• American Cancer Society. (2015). Neuroblastoma. Retrieved from Cancer.org: http://www.cancer.org/cancer/neuroblastoma/
• National Cancer Institute. (2016, January 20). Neuroblastoma. Retrieved from National Cancer Institute: http://www.cancer.gov/types/neuroblastoma/patient/neuroblastoma-treatment-pdq
• Frantz, C. (2014, September). Neuroblastoma. Retrieved from Kid’s Health: http://kidshealth.org/en/parents/neuroblastoma.html#

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