Thyroid cancer rates triple, and scientists look for cause

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THYROID cancer rates are rising faster than any other cancer in the United States, a new study found: Between 1975 and 2013, the number of thyroid cancer cases diagnosed yearly more than tripled.
The numbers have prompted many epidemiologists to caution in recent years that the increase in cases is really just a matter of doctors catching more cases. This includes cases that are slow-growing and that would be unlikely to cause symptoms that affect a person’s life. Doctors refer to the diagnosis of cases like this as the “overdiagnosis” of a condition. But in the new analysis, scientists argued that the alarming rise isn’t just due to improvements in detecting thyroid cancer.
“While overdiagnosis may be an important component to this observed epidemic, it clearly does not explain the whole story,” said Dr. Julie Sosa, one of the authors of the new study and the chief of endocrine surgery at Duke University in North Carolina.
Sosa, along with epidemiologists at the National Cancer Institute, acknowledged in their new study that better tools — from diagnostic ultrasound to fine-needle biopsies — have improved doctors’ ability to detect thyroid cancers. But the study, published today (March 31) in the Journal of the American Medical Association (JAMA), said that thyroid cancer is a real, growing threat, as shown by the increasing cases of a type of thyroid cancer called advanced stage papillary thyroid cancer, along with a steady rise in deaths from the disease.
In the study, the team analyzed more than 77,000 cases of thyroid cancer documented in a National Cancer Institute (NCI) database between 1974 and 2013. Along with the tripling in cases over that period, the researchers noted that between 1994 and 2013, cases of advanced forms of thyroid cancer rose by about 3 percent each year, and deaths from the disease rose by about 1 percent each year.
In the period from 1974 to 1977, there were 4.6 cases of thyroid cancer per 100,000 people diagnosed yearly in the U.S. That number reached 14.4 cases per 100,000 people yearly in the period from 2010 to 2013. Currently, more than 60,000 Americans are diagnosed each year with a form of thyroid cancer, according to the NCI. About 75 percent of these patients are women, and 82 percent are white, the researchers found. That deaths from thyroid cancer are increasing, despite it being among the most treatable and least lethal forms of cancer, is worth noting, Sosa said.