A new study about the use of imaging tests on patients who've had thyroid cancer has raised concerns about diminishing returns regarding additional imaging.

The study, published in The BMJ on Wednesday, highlights the importance of avoiding unnecessary imaging after a patient has been treated for thyroid cancer.                                            

Researchers at the University of Michigan Comprehensive Cancer Center in Ann Arbor, Michigan, used national cancer data from the Surveillance Epidemiology and End Results-Medicare databases to identify more than 28,000 patients diagnosed with thyroid cancer between 1998 and 2011 and looked at the usage of imaging on those patients.

They found that 57 percent of patients had at least one ultrasound, 24 percent had a radioiodine scan and 15 percent had a PET scan. These patients were more likely to have additional treatments like surgery, radioactive iodine treatment and radiation therapy, but were not more likely to die than those who didn’t have imaging tests performed.

"Over time, we have seen this marked increase in the use of imaging after primary treatment of thyroid cancer despite the fact that the majority of our patients have low-risk cancer,” said Megan Haymart, MD, assistant professor of medicine at the University of Michigan Medical School, in a statement. “For the most part this imaging isn't affecting survival.”

The study was observational, meaning that the researchers could not make any definitive conclusion about the effect imaging has on thyroid cancer, but they could conclude that more imaging usage is not necessarily better for the patient.

The study simply provides the foundation needed to reassess how thyroid cancer is monitored and how to reduce unnecessary imaging. The next steps include examining how cost effective the tests are and understanding whether patients or their providers are advocating for them.