A study from the Mayo Clinic Center for the Science of Health Care Delivery finds that advances in imaging technologies, including ultrasound, computed tomography, and magnetic resonance imaging, are fueling an epidemic in the diagnosis and treatment of thyroid cancers that are unlikely to ever cause symptoms or death, exposing patients to unnecessary and harmful treatments.1
The new technologies can detect thyroid nodules as small as 2 mm, many of which are papillary thyroid cancers, the most indolent form of thyroid cancer. According to the study, in the United States, the incidence of thyroid cancer has increased from 3.6 cases per 100,000 in 1973 to 11.6 cases per 100,000 in 2009, with small papillary thyroid cancers accounting for 90% of the cases.
“High-tech imaging technologies such as ultrasound, CT, and MRI can detect very small thyroid nodules many of which are slow-growing papillary thyroid cancers. This is exposing patients to unnecessary and harmful treatments that are inconsistent with their prognosis,” said Juan Pablo
Brito, MBBS, in a statement. Dr. Brito is an Endocrine Fellow and Health-Care Delivery Scholar at Mayo Clinic and lead author of the study.
The researchers said the expanding gap between the incidence of thyroid cancer and stable death rates from papillary thyroid cancer (0.5/100,000 in both 1979 and 2009) suggests that low-risk cancers are being overdiagnosed and overtreated. Overdiagnosing and overtreating these low-risk cancers, said the researchers, often results in unnecessary thyroidectomies, which are costly, carry a risk of physical complications, such as low calcium levels and nerve injury, and require lifelong thyroid replacement therapy.
Coining a New Term
Rather than labeling these small lesions as cancer, Dr. Brito and his colleagues suggest a new term that connotes a favorable prognosis for low-risk thyroid cancers: micropapillary lesions of indolent course (microPLIC). The new term, said the researchers, would make it easier for clinicians to offer patients the choice of active surveillance instead of immediate and often intensive and expensive treatment. ■
Disclosure: The study authors reported no potential conflict of interest.
1. Brito JP, Morris JC, Montori VM: Thyroid cancer: zealous imaging has increased detection and treatment of low risk tumors. BMJ 347:4706, 2013.