An increasing gap between the incidence of thyroid cancer and deaths from the disease suggests that low-risk cancers are being overdiagnosed and overtreated, according to researchers from the Mayo Clinic in Rochester, MN (BMJ, August 27, 2013).
Imaging modalities such as ultrasound, CT, and MRI can detect very small thyroid nodules, many of which are slow-growing papillary thyroid cancers, according to lead author Juan Pablo Brito, MBBS, an endocrine fellow and healthcare delivery scholar at Mayo.
Even though small papillary thyroid cancers are unlikely to cause morbidity or premature mortality in patients without a family history of thyroid cancer or radiation exposure, their diagnosis usually triggers intensive and unnecessary treatment, according to Dr. Brito and colleagues.
"This is exposing patients to unnecessary and harmful treatments that are inconsistent with their prognosis," he said in a news release.
Surgical removal of all or part of the thyroid gland is a costly procedure and includes a risk of complications such as low calcium levels and nerve injury, Dr. Brito noted. Surgical removal procedures in the U.S. have tripled in the past 30 years -- from 3.6 per 100,000 people in 1973 to 11.6 per 100,000 people in 2009.
Uncertainty about the benefits and harms of immediate treatment for low-risk papillary thyroid cancer should spur clinicians to engage patients in shared decision-making to ensure treatment is consistent with the research evidence and patient goals, according to Dr. Brito.
Dr. Brito and his colleagues have proposed that low-risk lesions be given a new name to convey their favorable prognosis and to help avoid overtreatment. The group defines these lesions as those smaller than 20 mm in patients with no family history of thyroid cancer or personal history of radiation exposure and no ultrasound evidence of extraglandular invasion.
