Pediatric MIBG Therapy for Neuroblastoma

What is MIBG therapy?

MIBG therapy is a treatment for neuroblastoma that isn't responding to other therapies or has come back after treatment. It may also be used to treat pheochromocytoma or paraganglioma (two other types of cancer).

MIBG stands for metaiodobenzylguanidine, an injectable compound that attaches to and is absorbed by neuroblastoma cells. By combining MIBG with radioactive iodine, the treatment attacks neuroblastoma in a highly targeted way. When the tumor cells take in the MIBG, they also get a strong dose of radiation, which gradually destroys them.

MIBG therapy is sometimes combined with chemotherapy or other medications to make neuroblastoma cells more sensitive to the MIBG. Your child's doctor will decide whether your child should be treated with MIBG alone or in combination with other medications.

Only a few medical centers offer MIBG therapy, with UCSF Benioff Children's Hospitals among them. Currently, it's provided only through a clinical trial (a study evaluating a promising treatment with human volunteers). Learn more about the process and benefits of participating in a clinical trial.

What is MIBG scanning?

In addition to its use as a treatment, MIBG is used to detect neuroblastoma and certain other cancers in an imaging test called an MIBG scintiscan. A low dose of radioactive material is combined with the MIBG compound and then injected into a vein. Special imaging technology shows where the radioactive material gathers, indicating the presence of a tumor.

Before or during the test, your child may be given an iodine solution to protect their thyroid gland, which is especially sensitive to radiation.

What happens during MIBG therapy?

To receive MIBG therapy, your child is admitted to the hospital. The medication is injected through an intravenous (IV) catheter (a thin, flexible tube that can be placed in a vein). The procedure itself takes about two hours and is painless, except for the initial needle prick. Your child will be given iodine during and after treatment to keep the thyroid gland from absorbing radiation.

Most patients don't experience significant side effects, but they will emit radiation for four to five days after the procedure, so they have to be partially isolated during that time in a special room outfitted with lead shields. Parents are allowed some daily contact with their child each day, with the length of time depending on the amount of radiation detected.

For many kids, the most difficult part of the process is the boredom that goes with lying in bed for several days. Video games and other electronic devices are allowed, and the nurses and other staff will work with you to make sure your child is as comfortable and engaged as possible.

Does MIBG therapy have side effects?

Because MIBG therapy affects only cancer cells, it causes fewer side effects than standard chemotherapy or radiation therapy, both of which can damage healthy tissue.

MIBG makes the patient slightly radioactive, but this resolves within about a week. Some kids experience fatigue or nausea following the treatments. The most significant side effect is suppressed bone marrow activity, leading to low counts of red and white blood cells and platelets (because bone marrow makes these blood components). A transplant of stem cells – collected from the patient before the start of MIBG therapy – can restore healthy blood counts.

How effective is MIBG therapy?

MIBG therapy offers promise for patients with high-risk neuroblastoma. In a clinical trial led by UCSF researchers, the treatment decreased tumor size or the number of cancerous lesions for about 1 in 3 patients. Some patients saw all their tumorous growths disappear temporarily.

Because this therapy is not yet approved by the Food and Drug Administration (FDA), patients can access it only by participating in a clinical trial.