Mayo Clinic researchers say people are being over-diagnosed with low-risk thyroid cancers.

Many, as a result, have unnecessary surgery that risks complications.

"An increasing gap between the incidence of thyroid cancer and deaths from the disease suggests that low-risk cancers are being over-diagnosed and over-treated," says a Mayo statement about study results that appear in the current issue of the British Medical Journal. The study focused on diagnoses worldwide.

Juan P. Brito, a Mayo endocrine fellow and health-care-delivery scholar, said high-tech imaging techniques like CT and MRI have made it possible to detect very-small thyroid nodules, many of which are slow-growing.

Often, the diagnosis happens when someone gets a CT scan for some other reason and small thyroid nodules are noticed. The patient gets referred for more tests and is eventually told that the thyroid should be removed, a costly procedure that riskscomplications like low calcium levels and nerve damage.

Newsletter signup for email alerts

"This is exposing patients to unnecessary and harmful treatments that are inconsistent with their prognosis," Brito said.

Surgical removal of the thyroid has more than tripled in the past 30 years from 3.6 in 1973 to 11.6 per 100,000 people in 2009, according to Mayo.

The study was conducted by the Mayo Center for the Science of Health Care Delivery.

In an interview, Brito emphasized the importance of adding a new name for the subcategory of tumors that are small and non-aggressive.

The new term Brito and his team recommends connotes a favorable prognosis for low-risk thyroid cancers and might be coined "microPapillary Lesions of Indolent Course" or microPLIC, he said.

If physicians have a "micro" name to differentiate such lesions from aggressive forms of thyroid cancer, Brito said, it will help trigger a recognition that treatment should involve shared decision-making between the health provider and patient.

The patient will be educated about risk, watchful surveillance versus surgery and potential complications.

Brito said patients newly diagnosed with thyroid cancer should ask their physicians:

• What kind of cancer is this?

• What is the risk of not doing surgery?

• What is the risk of doing surgery?

• After surgery happens, what types of followup will be needed?

• Without surgery, what types of followup will be needed?

Already, Brito said, Mayo researchers are using data from the Rochester Epidemiology Project to study the risk factors of thyroid-cancer over-diagnosis and, according to Mayo, he calls for research to identify the appropriate care for patients with low-risk cancers.