Answer to Question #11382 Submitted to "Ask the Experts"

Category: Radiation Effects — Effects on Tissues and Organs

The following question was answered by an expert in the appropriate field:

Q

In 1972, I received a radioactive iodine test because I was having seizures. Afterwards it was discovered that I had been two months pregnant at the time of the test. I was given the choice to have an abortion but chose not to. My son grew up healthy but at the age of 38 he developed a glioblastoma Grade IV brain cancer. Is it possible that the iodine test contributed to this?

A

The types of cancers that may be associated with ionizing radiation exposure are a small percent of all the different types of cancer that we may develop in a lifetime. The gamma-ray radiation that comes from iodine testing, used to look at possible thyroid conditions, is a source of radiation. Glioblastoma brain cancer is not one of the types of cancer associated with radiation exposure. Additionally, the few types of cancers that may be linked to radiation should appear sooner than 20 years after the exposure, and those exposed while still in the womb have lower risks than those exposed during childhood.

The types of cancer that may be associated with radiation exposure are listed by the American Cancer Society which states:

"Much of what we know about cancer risks from radiation is based on studies of the survivors of the atomic bombs in Nagasaki and Hiroshima. These people had higher risks of some, but not all cancers. Studies have found an increased risk of the following cancers (from higher to lower risk):

  • Most types of leukemia (although not chronic lymphocytic leukemia)
  • Multiple myeloma
  • Thyroid cancer
  • Bladder cancer
  • Breast cancer
  • Lung cancer
  • Ovarian cancer
  • Colon cancer (but not rectal cancer)
  • Esophageal cancer
  • Stomach cancer
  • Liver cancer
  • Lymphoma
  • Skin cancer (besides melanoma)

For most of these cancers, the risk was highest for those exposed as children, and was lower as the age at exposure increased. Those exposed while still in the womb (in utero) had lower risks than those exposed during childhood.

Higher radiation exposure was linked to higher risk of cancer, but even low amounts of radiation were linked to an increased risk of getting and dying from cancer. There was no clear cut-off for safe radiation exposure.

These cancers took years to develop, but some cancers appeared sooner than others. Deaths from leukemia went up about two to three years after exposure, with the number of cases peaking after about 10 years and going down after that. Solid tumors took longer to develop. For example, excess deaths from lung cancer began to be seen about 20 years after exposure."

John Hageman, CHP

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