Thyroid cancer appears to be on the rise in many areas of the world, although recent research suggests this may be more due to over-diagnosis than an actual increase in incidence.
In the US, the rate of thyroid cancer has doubled since 1994.1 In South Korea, it has become the most commonly diagnosed type of cancer, having increased 15-fold in the past 20 years.
However, some cancer experts note that the situation in South Korea is likely due to increased screening and misdiagnosis of harmless tumors. As noted in the featured article:2
“South Koreans embraced screening about 15 years ago when the government started a national program for a variety of cancers — breast, cervix, colon, stomach and liver.
Doctors and hospitals often included ultrasound scans for thyroid cancer for an additional fee of $30 to $50… Although more and more small thyroid cancers are being found, however, the death rate has remained rock steady, and low.
If early detection were saving lives, death rates should have come down. That pattern — more cancers detected and treated but no change in the death rate — tells researchers that many of the cancers they are finding and treating were not dangerous.”
The Risks of Over-Diagnosis
Finding tiny benign tumors that really do not need treatment is known as over-diagnosis—a phenomenon that is also common in other kinds of cancer screening, particularly breast cancer.
It’s emotionally difficult to take a “wait and see” approach once a tumor has been noted on a test or scan, but treating it can do far more harm than good if it’s benign. Far more people die with thyroid cancers than from them.
Left alone, a benign, slow-growing tumor might never cause a problem—indeed as many as one-third of people die with small thyroid tumors that remained undetected throughout their lives,3 and the cancer didn’t actually cause their death.
Removing and treating harmless tumors, however, can lead to a slew of cascading health problems. For example, surgical removal of your thyroid means you need to take thyroid hormones for the remainder of your life.
For many, this will lead to less than optimal hormone function. Chronic hormone deficiency, depression, and other symptoms of low thyroid function can become lifelong companions as a result… Surgical removal of the thyroid can also result in accidental damage to your vocal cords and/or parathyroid glands.
In South Korea, two percent of patients suffer vocal cord paralysis, and 11 percent end up with hypoparathyroidism as a result of damage to the parathyroid glands—the latter of which detrimentally affects calcium regulation in your body.
Experts Call for Restraint in Screening for Thyroid Cancer
The answer, some cancer experts say, is to simply reduce screening that finds these tiny, harmless cancers. One of the South Korean authors of the featured paper4 goes so far as to propose thyroid cancer screening should be banned. As noted by the New York Times:
“[C]ancer experts said the situation in South Korea should be a message to the rest of the world about the serious consequences that large-scale screening of healthy people can have.
‘It’s a warning to us in the US that we need to be very careful in our advocacy of screening,’ said Dr. Otis W. Brawley, chief medical officer at the American Cancer Society. ‘We need to be very specific about where we have good data that it saves lives.’
…These tiny cancers, called papillary thyroid cancers, are the most common kind and are the sort typically found with screening. They are known to be the least aggressive.
The epidemic was not caused by an environmental toxin or infectious agent, said Dr. H. Gilbert Welch of Dartmouth, an author of the paper.5
‘An epidemic of real disease would be expected to produce a dramatic rise in the number of deaths from disease,’ he said. ‘Instead we see an epidemic of diagnosis, a dramatic rise in diagnosis and no change in death.’
…[T]he lesson from South Korea should be heeded, said Dr. Barnett S. Kramer, director of the division of cancer prevention at the National Cancer Institute. ‘The message for so long is that early detection is always good for you,’ he said.
But this stark tale of screening gone wrong ‘should acutely raise awareness of the consequences of acting on the intuition that all screening must be of benefit and all diagnoses at an early stage are of benefit.’”
One in Eight Women Have Thyroid Disease
While the actual incidence of thyroid cancer may not be on the rise, thyroid disease has become very prevalent in today’s world, courtesy of a number of different lifestyle factors.
According to Dr. Christiane Northrup, MD, one in eight women aged 35-65 has some form of thyroid disease6—underactive thyroid being the most common. More than one-quarter of women in perimenopause are diagnosed with hypothyroidism, in which insufficient amounts of thyroid hormone is produced.
Thyroid hormones7 are used by every cell of your body, which is why the symptoms can vary so widely. For example, thyroid hormones regulate metabolism and body weight by controlling the burning of fat for energy and heat. Thyroid hormones are also required for growth and development in children. Symptoms of hypothyroidism may also include but are not limited to the following:
Written by Dr. Mercola
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