The Increase in Thyroid Cancer

While the incidence of many cancers is declining, thyroid cancer is one that is steadily soaring, especially in women. It’s got everyone wondering why this hormonal powerhouse is taking such a hit.

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Why is Thyroid Cancer on the Rise?
It's not clear what is causing this upward trend in thyroid cancer diagnoses. Some think the increase is attributed to improved and more precise diagnostic technology, like imaging and biopsy techniques, because the increase incidence was primarily from hard to detect, tiny tumors. Still, there are some reasons to believe that other factors may be involved.

When the number of people diagnosed with a condition climbs inexplicably, doctors look for clues to help explain it. Thyroid cancer is 4 times more common in women then men, so the finger naturally points to estrogen. And it has been suggested in some studies that estrogen might fuel the growth of thyroid cancer cells, which have surface receptors with a particular affinity for estrogen. (Estrogen also fuels some types of breast cancers.)

Interestingly, the increase in thyroid cancer also began to rise just as X-ray radiation was being routinely used to diagnose and treat disease. This was a time when X-rays were not only stronger, but also used indiscriminately for some unworthy conditions such as acne and tonsillitis. It was even used to measure foot size in the local shoe store.

The thyroid gland however, is very sensitive to radiation; it is a leading risk factor for the condition, especially if exposure occurred during childhood. Additionally, the thyroid can be inadvertently exposed during high-dose radiation therapy targeted to treat other types of cancer, particularly if the radioactive beam enters an area close to the gland such as the chest, neck and head, or from total body radiation used prior to bone marrow transplantation.

And although routine dental X-rays, chest X-rays and mammograms of today use much lower and safer amounts of radiation, some worry about this as a thyroid-damaging source. Some professionals say to protect the thyroid people should wear a lead thyroid shield (and apron when possible) when undergoing these procedures block radiation reaching the thyroid gland, and to limit tests using X-rays to those that are absolutely necessary.

Other risk factors for thyroid cancer include hereditary conditions and iodine deficiency (rare in the US because of iodized salts).