Over-diagnosing thyroid cancer

In last week’s post, I mentioned that in the US, thyroid cancer rates have more than doubled since 1994. But cancer experts agree that cases of thyroid cancer have not actually increased; they have simply been over-diagnosed. In South Korea, the reason they’re over-diagnosed is that doctors are actively looking for cancer through screening. In the US and Europe, where screening for thyroid cancer is not a common practice, small tumors may be discovered when patients are scanned for other conditions, such as when performing ultrasound exams of the carotid artery. The result of all this screening for this and that is that the doctors are in fact finding very tiny tumors—tumors that are non-aggressive and unlikely to amount to anything. (In fact, on autopsy, as many as a third of all people were found to have thyroid cancers that were never a problem.)

But here’s the thing: even though more tumors are being detected, the death rate from thyroid cancer has remained both low and steady. If early detection were saving lives, death rates should have come down. They have not.

What’s more, unnecessary screening for thyroid cancer has led to some aggressive and unnecessary surgical procedures—some of which have been disastrous (“Oops. Cut a vocal cord.” This happened in two percent of the surgeries in South Korea.)

Many in the medical profession counsel a “wait and see” approach—just leaving a newly-detected tumor alone. However, they’re finding it a tough sell. For one thing, fearful patients are reluctant to take the “do nothing” advice. What’s more, as one doctor said, “In the US, we have a fear that if we miss a cancer, the patient will sue.”

Doing nothing would definitely be my choice.

Next week: Tests as a revenue source for doctors.

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