Thyroid cancer among women is skyrocketing all over the world. Incidence is growing faster than for any other cancer. This has been going on for a long time, and the reasons why remain elusive.

The prevailing view is that there’s been an “epidemic of diagnosis” —that is, overdiagnosis— particularly following a screening program. The tumors have always been there, the argument goes, but new and better detection tools (ultrasound, for example) have made it easier to spot small ones, many of which would likely never present a real threat. In any case, thyroid cancer is not one of the bad ones; 98-99 percent of those diagnosed survive at least five years, the highest for all cancers. Watchful waiting is often the best prescription.

The only recognized cause for thyroid cancer is ionizing radiation.