In South Korea, more people were diagnosed with thyroid cancer between 1993 and 2011—not because more people were getting sick, but because doctors started using ultrasound scans to check everyone’s necks, even if they felt fine, and found lots of tiny, harmless tumors that would never have caused problems.

In South Korea, more and more people started finding thyroid cancer through routine scans between 1999 and 2008 — and this happened right after doctors began using ultrasound machines much more often thanks to new health rules.

In South Korea, more people were diagnosed with tiny thyroid lumps between 1999 and 2008—not because more people got sick, but because doctors started scanning for them more often with fancy tests.

In South Korea, more people were getting their thyroids checked with scans between 1999 and 2008, and as a result, way more thyroid cancers were found—way more than would’ve been found just by doctors noticing symptoms. This suggests the rise in diagnoses is mostly because of all the extra screening, not because more people were actually getting sick.

In South Korea, between 1999 and 2008, doctors started finding a lot more tiny thyroid cancers—so many that the overall number jumped more than six times. But almost all of these were very small tumors that probably wouldn’t have caused any harm if left alone.

In South Korea, most of the rise in thyroid cancer diagnoses between 1999 and 2008 was from tiny tumors that almost never kill people — doctors were just finding them more often, not because more people were getting deadly cancer.