November 10, 2014 — The Downside of Early Diagnosis

I read in the New York Times the other day about an “epidemic” of thyroid cancer in South Korea: a fifteen-fold increase in what had been, until recently, a relatively rare cancer. Thyroid cancer is now the leading cancer in that country.  (H. Gilbert Welch, "An Epidemic of Thyroid Cancer?" New York Times, November 5, 2014.)

How to account for the increase? A team of researchers set out to discover the reason.

After gathering their data and running the numbers they came up with the culprit: increased diagnosis.

Yes, diagnosis. Beginning in 1999, the government health program started paying for cancer screenings. Many doctor’s offices are equipped with relatively inexpensive ultrasound machines, so they naturally ordered up the test. Drastically increase the number of screenings and you’ve got — you guessed it — a greater number of diagnoses.

It’s not that there was an increase in thyroid cancer. There was an increase in the ability to diagnose the cancers that were already there.

That may seem like a good thing, but it’s actually a bit more complicated than that. As the article goes on to explain:

“Where did all those new thyroid cancers come from? They were always there. As early as 1947 pathologists recognized that, although it was a very rare cause of death, thyroid cancer was a frequent finding during autopsies. Studies have since shown that over a third of adults have thyroid cancer. Virtually all of these cancers are small ‘papillary thyroid cancers,’ many of which will never become evident during a person’s life.

Unless that person receives a screening ultrasound. In fact, virtually all the newly identified thyroid cancers in Korea are papillary thyroid cancers. How do we know this is not a real epidemic of disease? Because the number of Koreans dying from thyroid cancer has not changed. If the screening were saving lives, the death rate would decline, or increase more slowly as the epidemic spread — but not stay perfectly flat.”

I was diagnosed with papillary thyroid cancer a few years ago and had my thyroid gland removed. I had no physical complaint at the time. I wouldn’t have known I had it, were it not for the regular CT scans I was having at the time (monitoring me for a recurrence of lymphoma).

I take a thyroid-hormone replacement pill (Synthroid) every day, and calcium supplements (Extra-Strength Tums) twice a day, because my blood tests following the surgery indicated calcium deficiency (a common side effect of thyroid surgery, due to damage to the nearby parathyroid glands). That’s no great inconvenience, but if I went a couple of weeks without my Synthroid, I’d be pushing up the daisies.

Was my surgery necessary? Would watch-and-wait have been more appropriate? There’s no way to tell for sure. Complicating the decision, of course, was the fact that I was already a cancer survivor at the time the thyroid tumors were found.

Still, I wonder...