A childhood cancer treated with radioactive iodine that hunts the cells down

Neuroblastoma forms in neuroblasts — immature nerve tissue that would
normally become working nerve cells. In neuroblastoma they form a tumour
instead.

It usually begins in the adrenal glands, one on top of each kidney, which
make the hormones controlling heart rate, blood pressure, blood glucose and
the body's response to stress. It may also begin in the **neck, chest or
spinal cord**.

It is caused by changes in genes. **In most cases the cause of the mutation is
unknown**; sometimes it is inherited from a parent.

Symptoms, and why they are so scattered

**Neuroblastoma often begins in early childhood, and sometimes before a child
is born.** Most symptoms come from the tumour pressing on nearby tissue as
it grows, or from spread to the bone — which is why the list looks
unrelated:

• A lump in the abdomen, neck or chest
• Bulging eyes, and dark circles around the eyes
• Bone pain
• Swollen stomach and trouble breathing in babies
• Painless, bluish lumps under the skin in babies
• Weakness or paralysis

There is no single symptom to watch for; the presentation depends entirely on
where the tumour is and what it is pressing against.

The MIBG trick

Diagnosis uses a medical history, a neurological exam, blood and urine tests,
a biopsy, bone marrow aspiration and biopsy, and imaging — x-ray, CT,
ultrasound, MRI, or an MIBG scan.

In an MIBG scan, a small amount of a radioactive substance is injected,
travels through the bloodstream, and **attaches itself to neuroblastoma
cells**, which a scanner then detects.

And the treatment list contains iodine 131-MIBG therapy: the same
attraction, with a therapeutic dose. **The radioactive iodine collects in
neuroblastoma cells and kills them with the radiation it gives off.**

One biological property — these cells take up MIBG and other cells do not —
serves as both the way to find the disease anywhere in the body and the way to
treat it there.

The other treatments

• Observation (watchful waiting), with no treatment until signs or
  symptoms appear or change
• Surgery
• Radiation therapy
• Chemotherapy
• High-dose chemotherapy and radiation with stem cell rescue — the high
  doses kill cancer cells and healthy cells alike, so a **stem cell
  transplant**, usually of the child's own cells collected earlier, replaces
  what was lost
• Targeted therapy, attacking specific cancer cells with less harm to
  normal ones

Source: National Cancer Institute, via MedlinePlus.