Pathophysiology of Neuroblastoma

Elaboration , 2018 , 7 Pages , Grade: 1

Medicine - Epidemiology

Neuroblastoma refers to a malignant cancer disease that affects the nerve tissue in different parts of the body, primarily the nerve tissue of the spinal cord, adrenal glands, chest and neck. However, the disease is believed to begin from the adrenal glands and spread to the other nerve tissues. In most cases, neuroblastoma sets in the early childhood, especially in children below the age of 5 years, and persists into adulthood. In rare occasions, malignant cancer cells form during the fetal development stages of the fetus, long before the child is born, as it has been identified in ultrasound results.

In practice, neuroblastoma presents some difficulties in both management and diagnosis because this cancer spreads rapidly and this explains why diagnosis is usually done when the disease has already metastasized to the bones, lymph nodes, skin and the liver.

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Neuroblastoma refers to a malignant cancer disease that affects the nerve tissue in

different parts of the body, primarily the nerve tissue of the spinal cord, adrenal glands, chest

and neck. However, the disease is believed to begin from the adrenal glands and spread to the

other nerve tissues. In most cases, neuroblastoma sets in the early childhood, especially in

children below the age of 5 years, and persists into adulthood. In rare occasions, malignant

cancer cells form during the fetal development stages of the fetus, long before the child is

born, as it has been identified in ultrasound results. In practice, neuroblastoma presents some

difficulties in both management and diagnosis because; this cancer spreads rapidly and this

explains why diagnosis is usually done when the disease has already metastasized to the

bones, lymph nodes, skin and the liver

i

.

Currently, neuroblastoma is ranked third among the most common cancers in children

after cancer of the central nervous system and leukemia. In Ireland, the prevalence rate of

neuroblastoma has been identified as 5.6%, which is relatively higher that the prevalence

rates of the entire Europe that is estimated to be 3.4%

ii

. Research data on the prevalence of

childhood cancers in the United Kingdom indicates that, neuroblastoma has the highest

incident rate in children aged three years in which its rate is estimated to be 22% per million

children

iii

. Globally, neuroblastoma accounts for 7% of childhood cancers

iv

.

Neuroblastoma is usually manifested through numerous signs and symptoms.

Ordinarily, the most common signs and symptoms are associated to the pressure exerted by

the tumor on the adjacent tissues. Some of the most common signs and symptoms of this

disease include the formation of a lump in the neck, chest or the abdomen. In some occasions,

the disease is manifested by swollen stomach, especially in infants in which breathing

complications develop. Paralysis is also another significant sign of neuroblastoma in which

infants lose the ability to move some body parts such as the head, legs and arms. It can also

be manifested by dark circles that form around the infant's eyes. Other principal symptoms

include bleeding characterized with petechiae, severe watery diarrhea, high blood pressure

and jerky muscle movements. However, it is worth noting that, pains in the bones serve as

one of the most principal symptoms of neuroblastoma because it affects the bones and bone

marrow during its initial stages

v

.

Currently, there is no known cause of neuroblastoma, just like it is the case with most

cancers. However, some risk factors have been identified. Research indicates that age and

family history are some of the most principal risk factors that are associated with

neuroblastoma. In most cases, this cancer occurs in populations with less than 10 years in

which infants and babies are the most affected. This is so because its incidence rates have

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been found to be highest among children below the ages of 3 years, and it is relatively low in

children aged 10 years and above. Therefore, age appears to be one of the most significant

risk factors for neuroblastoma. The second risk factor for neuroblastoma is the family history

of inherited genetic abnormalities

vi

. Research indicates that, 1-2% of children who suffer

from neuroblastoma inherited the genetic abnormality from their relatives. As such, family

history of neuroblastoma is considered as one of the principal risk factors of the disease.

However, it is worth noting that, most neuroblastomas do not seem to exhibit inheritance

patterns

vii

.

On the other hand, diagnosis of neuroblastoma encompasses numerous tests and

investigations ranging from blood tests, biopsy and bone marrow tests to scans. Ideally, tests

are usually done to ascertain whether a child has neuroblastoma or not. They also help in

determining the spread of the cancer because neuroblastomas exhibit rapid metastasis. On the

other hand, nuclear medicine scans are done to identify the exact location of the tumor, in

order to decide on the most appropriate treatment option. Some of the most reliable tests for

diagnosing neuroblastoma are Vanillylmandelic acid (VMA) test and Homovanillic acid

(HVA) test, in which urine samples are collected and analyzed for the presence of

homovanillic acid and vanillylmandelic acid levels. These tests are essential in the diagnosis

of neuroblastoma because; 9 of 10 children with neuroblastoma show increased levels of

these two metabolites in their urine; thus, it helps in confirming diagnosis. In addition, VMA

and HMA tests play a significant role in monitoring the progress of treatment by observing

the decrease of these compounds in urine samples of neuroblastoma patients. Other reliable

diagnostic methods are biopsies and metaiodobenzyl guanine (MIBG) scans. In biopsy

diagnosis, tissue lesions are collected during an operation for microscopic and histological

investigations. On the other hand, MIBG scans employ the principle of radiation scanning to

determine the exact location of neuroblastoma tumors. In this diagnostic approach,

metaiodobenzyl guanine, a radioactive substance is injected into the patient's blood

circulation, whereby it is taken up by tumor cells; thus allowing easy location. Therefore,

radiation scanning determines the levels of radioactive iodine to identify the location of the

tumor

viii

.

Treatment for neuroblastoma involves numerous treatment modalities. These

treatment options usually depend on the size and position of the tumor, as well as, the age of

the child. They also depend on the tumor biology, primarily regarding the extent of

metastasis. Over the years, chemotherapy, surgery and radiotherapy have been the mainstay

of neuroblastoma treatment. However, new therapies including stem cell therapy and

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monoclonal antibody treatment are currently being incorporated in the treatment of

neuroblastoma.

In practice, surgery is usually used as the most appropriate treatment option for

localized tumors. This approach involves the removal of the tumor to prevent neuroblastoma

from spreading to other parts of the body. In most cases, localized tumors are observed

during the early stages of neuroblastoma. During the early stages of the cancerous tumor

development, lymph nodes and the bones are not affected so, an operation to remove the

tumor prevents further development of malignant tumor cells. Evidence shows that surgery in

combination with chemotherapy results into cure of neuroblastoma when diagnosis is done

during its onset. However, it is worth noting that, some of the localized tumors are difficult to

remove owing to their locations such as within the bone tissue or the spinal cord.

In high-risk neuroblastoma, radiotherapy is used as the most appropriate treatment

option. Radiotherapy is also useful in treating metastasized tumors in which high-energy

radiation rays are used to destroy the cancerous cells. However, it is worth noting that there

are two forms of radiotherapy: external and internal radiotherapy. In external radiotherapy,

high-energy rays from an external machine are directed to the affected regions; thus, causing

destruction to the tumor cells while preserving normal cells. On the other hand, internal

radiotherapy involves the use of radioactive MIBG, in which high doses of radioactivity kills

the cancer cells

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.

On the other hand, chemotherapy is used in metastasized, as well as, in high-risk

tumors. This therapy aims at killing cancer cells in the body through the use of cytotoxic

(anti-cancer) drugs. Evidence shows that, cytotoxic drugs shrink tumors; thus, preventing the

spread of neuroblastoma in the body. However, it is worth noting that, intensive

chemotherapy is required in achieving appreciable treatment outcomes.

Moreover, new therapies have been developed including the stem cell coupled high-

dose chemotherapy and monoclonal antibody treatment. In treating metastasized

neuroblastoma, stem cell support is coupled with high-dose chemotherapy, primarily after the

initial stages of chemotherapy treatment

x

. Ordinarily, high-dose chemotherapy destroys

cancer cells, although it causes harm to the normal cells because high levels of cytotoxic

drugs are lethal to both cancerous and healthy cells, especially the bone marrow cells. This

implies that, the synthesis of blood cells is impaired by the use of high-dose chemotherapy

xi

.

Therefore, stem cells are given in the form of a drip to a child after high-dose chemotherapy

to restore proper hematopoietic processes of the bone marrow leading to the replacement of

• College: Egerton University
• Grade: 1
• Author: Patrick Kimuyu (Author)
• Publication Year: 2018
• Pages: 7
• Catalog Number: V388315
• ISBN (eBook): 9783668624429
• ISBN (Book): 9783668624436
• Language: English
• Tags: Neuroblastma, cancer