Neuroblastoma

What is neuroblastoma?

Neuroblastoma is an aggressive cancerous tumor affecting infants and young children. These tumors start in the sympathetic nerve tissues, or the nerves responsible for the body's emergency "fight or flight" response.

The tumor usually begins in the tissues of the adrenal glands, which are in the abdomen on top of the kidneys. These glands secrete hormones and other important substances that are required for normal functions in the body such as the nervous system. The tumor also may begin in nerve tissue next to the spine in the neck, chest or pelvis.

Although neuroblastoma may be present at birth, it often isn't detected until the tumor has grown and compressed surrounding organs. It may also spread to lymph nodes, bones, the central nervous system or bone marrow. In rare cases, pediatric neuroblastoma can be detected before birth by a fetal ultrasound.

In the United States, about 600 children are diagnosed with neuroblastoma each year. It is the most common tumor found in children under 1.

Causes of neuroblastoma

Neuroblastoma is always linked to a genetic change that causes neuroblastoma cells to divide and grow uncontrollably. In most cases, the gene mutation is spontaneous, occurring for reasons unknown. In a small number of cases, the condition is caused by an inherited gene mutation.

Certain genetic conditions can increase a child’s risk of developing neuroblastoma. These include:

• Costello syndrome
• Noonan syndrome
• Neurofibromatosis type 1
• Li-Fraumeni syndrome
• Beckwith-Wiedemann syndrome
• Pheochromocytoma/paraganglioma syndromes
• ROHAAD syndromes (rapid-onset obesity, hypothalamic dysfunction, hypoventilation, and autonomic dysfunction)

Symptoms of neuroblastoma

The most common symptoms of neuroblastoma are caused by pressure from the tumor or bone pain from cancer that has spread to the bone and bone marrow.

Symptoms may include:

• Protruding eyes and dark circles around the eyes caused by cancer that has spread to the area behind the eye
• Paralysis from neuroblastoma that compresses the spinal cord
• Fever, anemia or high blood pressure

Other less common symptoms include:

• Severe diarrhea
• Uncoordinated or jerky muscle movements
• Uncontrollable eye movement

Symptoms also may include:

• A firm mass in the abdomen
• Difficulty breathing
• Weight loss
• Fever
• Bone pain
• Difficulty swallowing

Diagnosis of neuroblastoma

If your child has symptoms of neuroblastoma, blood and urine tests, tissue samples, and imaging studies will be needed. These diagnostic tests are important because many of the symptoms and signs of neuroblastoma also can be caused by other cancers or by non-cancerous diseases. The tests can confirm if your child has neuroblastoma or another condition.

Blood and urine tests for neuroblastoma

Your child's nerve cells release chemicals called neurotransmitters that control nerve activity. One type of neurotransmitter called catecholamines, is produced by the sympathetic nervous system. Elevated levels of catecholamines can be found in 90 to 95 percent of patients with neuroblastoma. Blood or urine tests measure these levels.

Your child's doctor may order additional blood tests to check liver and kidney function and salt balance. A urinalysis may be also done to further check kidney function.

Imaging tests for neuroblastoma

Imaging tests produce pictures of the body's interior. Two or more of these tests are generally used to identify tumors in areas where neuroblastomas grow or tend to spread. These tests may include:

• X-rays. This test captures images of the affected areas.
• Computed Tomography (CT) Scan. This test uses a combination of X-rays and computer technology to take cross-sectional pictures of the body.
• Magnetic Resonance Imaging (MRI). This scan is used for certain types and locations of tumors because they can produce a better image than X-rays.
• Ultrasound. An ultrasound exam uses sound waves to produce images of the affected areas.
• MIBG. A chemical called metaiodobenzylguanidine, or MIBG, that is slightly radioactive is used to identify areas where the neuroblastoma has spread. It is a very sensitive method of detecting the spread of cancer in bone and soft tissues.
• Positron Emission Tomography (PET) Scan. A PET scan is a nuclear medicine test that involves injecting a special compound to show the areas of tumor in the body. It's used in about 10 percent of the cases where the MIBG scan is negative.

Biopsies for neuroblastoma

Blood and urine tests and imaging studies may indicate that a neuroblastoma is likely present. However, to confirm a diagnosis your child will need a biopsy – a test where the tumor cells are collected and analyzed under a microscope.

If blood or urine levels of catecholamines or their metabolites are higher than normal, then finding cancer cells in a bone marrow biopsy is enough evidence to diagnose neuroblastoma. The disease spreads to bone marrow in about a quarter of patients. Bone marrow can be sampled in two ways, and both are generally done at the same time:

• Bone marrow biopsy. A large needle is used to remove a small sample of marrow, the soft tissue in the hollow part of bone.
• Bone marrow aspiration. A thinner needle and a syringe is used to extract a small amount of marrow in liquid form from inside the bone.

Your doctor may also take tissue samples from the primary tumor. If these samples show certain features of neuroblastoma, the doctor can make a clear diagnosis, even if catecholamine levels are normal. A doctor experienced in testing children's tumor samples can easily recognize neuroblastoma under a microscope.

Additional tests for neuroblastoma

Sometimes, the features of neuroblastoma can be easily confused with other types of children's cancers, making diagnosis more challenging. In those cases, special tests of the tissue samples are done, including:

• Immunohistochemistry. This test uses special laboratory antibodies to identify chemicals found in neuroblastoma cells. It can also use other antibodies that recognize chemicals of other cancer cells.
• Electron microscopy. This test uses a special microscope that is hundreds of times more powerful than a standard laboratory microscope and that can reveal otherwise undetectable abnormalities that indicate neuroblastoma.

Staging of neuroblastoma

When diagnosing neuroblastoma, your child's doctor may describe the cancer using the following categories or terms:

• Localized resectable. The cancer is confined to the original site. There is no evidence of spread, and the cancer can be surgically removed.
• Localized unresectable. The cancer is confined to the original site, but the cancer cannot be completely removed surgically.
• Regional. The cancer has extended beyond the original site to regional lymph nodes and/or surrounding organs or tissues. It has not spread to distant parts of the body.
• Disseminated. The cancer has spread from the original site to distant lymph nodes, bone, liver, skin, bone marrow and/or other organs (except as defined for stage 4S).
• Stage 4S. The cancer is localized, with spreading limited to liver, skin and to a very limited extent the bone marrow. Stage 4S also is called special neuroblastoma because it is treated differently.
• Recurrent. This means the cancer has come back or has continued to spread after treatment. It may come back in the original site or in another part of the body.

In addition to staging the cancer, the doctors will determine if the cancer is low-, intermediate- or high-risk. Risk is determined by various factors including the stage of the cancer, the child’s age, the aggressiveness of the cancer and how much of the tumor can be surgically removed. The risk level can affect the treatment plan. Low- and intermediate-risk patients have a good chance at being cured. High-risk neuroblastoma is more difficult to cure.

Treatment of neuroblastoma

Treatment options will depend on your child's age, the location and biology of the tumor, stage of the disease and the impact on surrounding lymph nodes. More than one method of treatment may be used, depending on your child's condition.

Surgery for neuroblastoma

If surgery is an option, it is used to remove as much of the cancer as possible. If the cancer can't be removed, surgery may be limited to a biopsy.

Radiation therapy for neuroblastoma

Radiation therapy uses high-energy rays to damage or kill cancer cells and shrink tumors. Radiation usually comes from a machine outside the body, an approach called external beam radiation therapy.

Chemotherapy for neuroblastoma

Chemotherapy uses drugs to kill cancer cells and shrink tumors. Chemotherapy drugs may be taken by mouth or injected into a vein or a muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body and can kill cancer cells throughout the body.

Chemotherapy may be given after the tumor has been surgically removed to kill any remaining cancer cells. This is called adjuvant chemotherapy. Chemotherapy also can be used to shrink the tumor before surgery. This is called neoadjuvant chemotherapy.

Bone marrow transplant for neuroblastoma

A bone marrow transplant (BMT) is a procedure where healthy bone marrow is used to replace bone marrow destroyed by anti-cancer drugs or radiation. At UCSF Benioff Children's Hospitals, the Bone & Marrow Transplant (BMT) Clinic offers autologous bone marrow stem cell transplants to treat children with high-risk neuroblastoma. This procedure uses high-dose chemotherapy to kill the tumor. Afterwards, the bone marrow is infused with the patient's own healthy bone marrow cells, which were previously removed and stored.

MIBG therapy for neuroblastoma

UCSF Benioff Children's Hospitals are one of the few centers in the country to offer MIBG therapy. This treatment is used for high-risk neuroblastomas that have not responded to chemotherapy or that have recurred after treatment. It may be provided alone or in combination with chemotherapy or other medication that make the neuroblastoma cells more sensitive to MIBG. The treatment is only available to patients participating in a clinical trial.

Intraoperative radiation therapy (IORT) for neuroblastoma

At UCSF, radiation oncologists are pioneering intraoperative radiation therapy (IORT) to treat challenging cases of neuroblastoma. We are one of the few medical centers in the United States that offers this treatment option.

IORT delivers a concentrated beam of radiation directly to neuroblastoma tumors during surgery. This targeted approach means that nearby healthy organs are protected from radiation exposure. Unlike traditional radiation therapy, which requires multiple sessions over weeks, IORT often only requires one treatment.

Advancements in high-dose therapy are improving survival rates for neuroblastoma patients. However, there are still challenges with high-risk tumors.

Treatment by category

As described earlier, neuroblastoma is categorized as localized resected, localized unresected, regional, disseminated and special. The treatment plan will vary, depending on the type of neuroblastoma.

Localized resectable neuroblastoma

Your child's treatment may be one of the following:

• Surgery to remove the cancer
• Surgery plus chemotherapy
• Surgery plus radiation therapy

Localized unresectable neuroblastoma

Initial treatment generally consists of surgery to remove as much of the cancer as possible, followed by chemotherapy. A second surgery may be performed to remove any cancer that remains. Radiation therapy also may be prescribed.

Regional neuroblastoma

Treatment depends on your child's age. If your child is younger than 1, treatment may include the following:

• Surgery to remove the cancer
• Chemotherapy

If your child is older than 1, treatment may be one of the following:

• Surgery to remove the cancer
• Surgery followed by chemotherapy
• Chemotherapy with or without radiation therapy to reduce the tumor, followed by surgery
• Multi-drug chemotherapy
• Radiation therapy
• New methods of treatment in a clinical trial or study

Disseminated neuroblastoma

Your child's treatment may be one of the following:

• Multi-drug chemotherapy with or without surgery and/or radiation therapy
• Chemotherapy followed by peripheral stem cell transplantation and 13-cis retinoic acid
• New methods of treatment in a clinical trial or study

Stage 4S neuroblastoma

Children with this special type of neuroblastoma may not require therapy. You may want to have your child take part in a clinical trial that provides new methods of treatment.

Recurrent neuroblastoma

The selection of treatment for recurrent or progressive neuroblastoma depends on the location and extent of the recurrence and previous therapy as well as individual circumstances. A clinical trial may be appropriate. UCSF Benioff Children's Hospitals participates in national and local studies for recurrent neuroblastoma, including new therapies with targeted radiation (I-131-MIBG), phase I trials of the New Approaches to Neuroblastoma Therapy (NANT) consortium and phase I and II trials of the Children's Oncology Group.

Recurrent or refractory neuroblastoma

Sometimes, neuroblastoma comes back after treatment (recurrent) or doesn't respond to initial treatment (refractory). The treatment options then depend on the location and extent of the cancer, previous therapy as well as individual circumstances.

• Low-risk recurrent or refractory neuroblastoma. Treatment may include surgery, chemotherapy and/or observation.
• Intermediate-risk recurrent and refractory neuroblastoma. Treatment options include surgery, radiation therapy, chemotherapy and options typically reserved for high-risk cases.
• High-risk recurrent or refractory neuroblastoma. There is no standard treatment for these cases; patients may benefit from therapy offered only in a clinical trial.

The Pediatric Oncology Clinic participates in national and local studies for these tumors, including new therapies with targeted radiation (I-131-MIBG), phase I trials of the New Approaches to Neuroblastoma Therapy (NANT) consortium and phase I and II trials of the Children's Oncology Group.