Neuroblastoma is the most common extracranial solid cancer in infancy and childhood. It is a neuroendocrine tumor, arising from any neural crest element of the sympathetic nervous system. Close to 50 percent of neuroblastoma cases occur in children younger than two years old.

Neuroblastoma is a cancer of the sympathetic nervous system -- a nerve network that carries messages from the brain throughout the body. Its solid tumors, which take the form of a lump or mass, commonly begin in one of the adrenal glands, though they can also develop in nerve tissues in the neck, chest, abdomen, or pelvis.

The cause of neuroblastoma is unknown, though most physicians believe that it is an accidental cell growth that occurs during normal development of the adrenal glands.

Neuroblastoma is one of the rare human malignancies known to demonstrate spontaneous regression from an undifferentiated state to a completely benign cellular appearance.

Neuroblastoma comprises 6-10% of all childhood cancers, and 15% of cancer deaths in children. The annual mortality rate is 10 per million children in the 0- to 4-year-old age group, and 4 per million in the 4- to 9-year old age group
The highest incidence is in the first year of life, and some cases are congenital. The age range is broad, including older children and adults, but less than 10% of cases occur in people older than 10 years of age.

The etiology of neuroblastoma is not well understood. Several risk factors have been proposed and are the subject of ongoing research. Due to characteristic early onset many studies have focussed on parental factors aroundconception and during gestation. Factors investigated have included occupation (i.e. exposure to chemicals in specific industries), smoking, alcohol consumption, use of medicinal drugs during pregnancy and birth factors, however results have been inconsistent.

The first symptoms of neuroblastoma are often vague and may include fatigue and loss of appetite. Later symptoms depend on tumor locations. In the abdomen, a tumor may cause a swollen belly and constipation. A tumor in the chest may cause breathing problems. Tumors pressing on the spinal cord cause a feeling of weakness. A tumor in the head may cause the eyes to start to swell outwards and turn black due to the pressure from behind. Often because symptoms are so unclear, half of all neuroblastomas have already spread (metastasized) to other parts of the body by the time suspicions are raised and a diagnosis is made.

 

Another way to detect neuroblastoma is the mIBG scan (meta-iodobenzylguanidine), but it doesn't diagnose the disease in 100% of the cases. It works like this: mIBG is taken up by sympathetic neurons, and is a functioning analog of the neurotransmitter norepinephrine. When it is radio-ionated with I-131 (a radioactive iodine), it is a very good radiopharmaceutical for diagnosis of this disease.

Neuroblastoma is stratified according to its anatomical presence at diagnosis:

When the lesion is localized, it is generally curable. However, long-term survival for children with advanced disease is poor despite aggressive multimodality therapy.

Recent biologic and genetic characteristics have been identified, which, when added to classic clinical staging, has allowed accurate patient assignment to risk groups so that treatment strategies can be more effectively undertaken. These criteria include the age of the patient, extent of disease spread, microscopic appearance, and several other biological features, most importantly MYCN oncogene amplification, into low, intermediate, and high risk disease. The therapy for these different risk categories is very different. Low risk patients can frequently be observed without any treatment at all, while intermediate risk patients are treated with chemotherapy. High-risk neuroblastoma is treated with intensive chemotherapy, surgery, radiation therapy, bone marrow / Hematopoietic stem cell transplantation and biological-based therapy with Cys-Retinoic acid (Accutane). With current treatments, patients with low and intermediate risk disease have an excellent prognosis with cure rates above 90%. In contrast, therapy for high-risk neuroblastoma results in cures only about 30% of the time.

After it is declared that the disease is gone, it often comes back. Further treatment is then required. This can be problematic because some treatments, such as chemotherapy, have cumulative effects and side-effects therefore can increase significantly if used again.

Intensive chemotherapy and radiation therapy have known long-term negative consequences. An estimated two of three survivors of childhood cancer will ultimately develop at least one chronic and sometimes life-threatening health problem within 20 to 30 years after the cancer diagnosis.