By Dr. Mercola
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:
Fatigue, loss of energy, and general lethargy Cold intolerance Muscle and/or joint pain Decreased sweating Depression Puffiness Weight gain Coarse or dry skin and hair Hair loss Sleep apnea Carpal tunnel syndrome Forgetfulness, impaired memory, and inability to concentrate Menstrual disturbances Decreased appetite Impaired fertility Constipation Fullness in the throat and hoarseness Increased risk of heart disease Increased “bad” cholesterol (LDL) Weakness in extremities Emotional instability Blurred vision Mental impairment Decreased hearing Bradycardia (reduced heart rate)
The Effect of Thyroid Disease on Mental Health
Depression and other mental health problems are perhaps particularly notable symptoms of thyroid dysfunction—if nothing else because it’s a common side effect that is easily overlooked and therefore misdiagnosed. If your depression is due to an underactive thyroid, clearly the answer to your problem is not an antidepressant but rather addressing your thyroid function... As explained by Dr. Northrup:
“The thyroid is a butterfly-shaped gland located in the area of your neck just below the Adam’s apple. It’s part of the endocrine system, and it secretes the hormones thyroxine (T4) and triiodothyroxine (T3), which regulate the body’s metabolic rate. Thyroid function is very complex and exerts a profound effect on the function of nearly every other organ in the body. Therefore, smooth functioning of the overall body chemistry depends on the health of your thyroid gland.
It is not uncommon for women with thyroid problems to suffer from depression. One explanation for this is that the most biologically active form of thyroid hormone, T3, is actually a bona fide neurotransmitter that regulates the action of serotonin, norepinephrine, and GABA (gamma aminobutyric acid), an inhibitory neurotransmitter that is important for quelling anxiety.”
It’s important to realize that thyroid dysfunction is a complex issue, with many variables. As noted by Dr. Northrup, midlife hypothyroidism can be related to underlying estrogen dominance, in which case taking thyroid hormone fails to address the root of the problem. Medications can also disrupt your thyroid function, in which case the most appropriate remedy may not be to add thyroid hormone.
Known thyroid-disrupting drugs include steroids, barbiturates, cholesterol–lowering drugs, the antiepileptic drug Dilantin, and beta-blockers. Heavy metal toxicity is yet another factor that can be part of the problem (to learn more about this, please listen to my interview with Dr. Jonathan Wright, below). Last but not least, Dr. Northrup8 also points out that thyroid disease oftentimes has an emotional/spiritual component:
“Thyroid disease is related to expressing your feelings, something that until relatively recently had been societally blocked for women for thousands of years. In order to have your say—and maintain your thyroid energy—you must take a fearless inventory of every relationship in which you feel you don’t have a say...
One more thing, thyroid disorders are also related to our relationship to time. The thyroid is adversely affected by feeling as though there’s never enough time or that you are running out of time. This feeling also results in adrenal burnout (which is related to thyroid disorders.). Our culture’s relationship to time is very unbalanced... A starting point here is to realize that you have all the time there is. Literally. And all the time that anyone else has—24 hours in a day.
You can change your relationship to time by changing the way you pay attention... Take regular moments during the day to simply put your attention on something. Notice a beautiful flower. Or a tree. Or the sky. Slow down and pay attention. Eventually this little practice will improve your relationship to time.”
Treating Overactive Thyroid
Take Control of Your Thyroid Health
Thyroid hormones are used by cells throughout your body, making it very important to address your thyroid health. Again, iodine is the key to a healthy thyroid, and it’s also important for the prevention of breast cancer. If you’re not getting enough from your diet (in the form of seafood), you’d be well advised to consider taking a supplement, ideally a high-quality seaweed supplement (be sure to check its source to avoid potential radioactive contamination), or other iodine-containing whole food supplement.
As for thyroid hormone replacement, you have two basic options: bioidentical or synthetic hormones.11 Bioidentical thyroid hormones—which are what I recommend using—include Nature-Throid and Westhroid. They’re made from desiccated pig thyroid glands and contain the full spectrum of thyroid hormones: T4, T3, T2, and T1. Synthroid (generic brand: Levothyroxine) is synthetic, and contains only T4. Keep in mind that in some cases, if you're borderline hypothyroid, you may actually only need an iodine supplement rather than a thyroid hormone replacement.
With regards to screening, there’s ample evidence suggesting that thyroid cancer screening is unnecessary unless you have reason to suspect cancer. Also remember that screening does not equate to prevention. Addressing your thyroid health is far more important and beneficial than relying on screening to alert you to a potential problem. Especially considering that the chances of over diagnosis are great, and treating an otherwise harmless tumor may result in greater harm than leaving it alone and simply focusing on lifestyle factors such as diet and detoxification to improve your thyroid health.