Use of RAI for Thyroid Cancer Comes Under Scrutiny

Haymart pointed to research from others that show "if you diagnose more low-risk disease, there's an inflated belief that the treatment is working when, in fact, the patient would have done fine either way. I'm sure that's playing a role."

Haymart, an endocrinologist who specializes in thyroid disease, is the lead author of a paper published Wednesday in the Journal of the American Medical Association. The project looked at 189,219 patients with well-differentiated thyroid cancer treated at 981 hospitals between 1990 and 2008.

The researchers highlighted the rapid rise in the use of radioactive iodine to treat thyroid cancer, which went from 40% in 1990 to 56% in 2008.  "After adjusting for patient, tumor, and hospital characteristics," they wrote, "29.1% of the variance was attributable to unexplained hospital characteristics."

The issue is controversial in large part because of the unexplained rise in diagnoses of thyroid cancer in recent years. Incidences are accelerating "at a faster rate than any other malignancy," but most are very small at the earliest stage, she said.

For example, in 2009, the National Cancer Institute estimated there would be 37,200 people diagnosed with thyroid cancer. In 2011, the American Cancer Society estimates, the number will be 48,020, with expected mortality this year at a relatively low 1,740.

While some speculate that environmental changes may be at the root of increased diagnoses, Haymart and others suspect that increased use of imaging is more likely the cause.

Instead of recognizing thyroid disease by palpation, cases are being captured through tests done for other reasons, such as during examinations after accidents or to rule out heart disease.