In 2015, South Korea decided not to routinely scan healthy people’s necks with ultrasound to check for thyroid cancer, because they thought it wasn’t helpful for most people.

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.

Getting an ultrasound of the thyroid if you have no symptoms doesn’t seem to help people live longer or prevent them from dying of thyroid cancer, according to a study in Korea.

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, many people and doctors didn’t want to stop checking for thyroid cancer so often, even when it might not be needed—some even said it was a right everyone should have, suggesting that money and institutions might be pushing unnecessary tests.

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.