A study published this week in the New England Journal of Medicine revealed that radiation therapy, the cornerstone of thyroid cancer care, may be of no benefit for low risk thyroid cancers. Researchers suggest that for this population, surgery alone might be sufficient without the need for follow-up treatment with radioactive iodine.

According to STAT News, David Cooper, M.D., an endocrinologist at the Johns Hopkins University School of Medicine, said that for decades it has been a “given that once patients have their thyroid taken out, they get radioactive iodine.” He said that recently experts have been wondering whether the potential harm is worth the potential benefit.

In the past, research found that radioactive iodine reduced mortality and chance of relapse in thyroid cancer patients, said Sophie Leboulleux, M.D., co-author of the study and an oncologist at Gustave-Roussy Cancer Institute in France.  “But times have changed. Thyroid cancers are not discovered at the same stages they were 25 years ago.”

Thyroid cancers are now detected earlier and more frequently, and often incidentally, thanks to CT scans and ultrasounds of the head and neck. Often these are small, low-risk cancers said Leboulleux, and clinicians started to wonder if surgery alone would be sufficient to treat them without the added expense of radiation.

Leboulleux and her team recruited 730 patients with low risk differentiated thyroid cancer with tumors two centimeters or less in width. The study subjects were divided into two groups. One group received no radioactive iodine after surgery, while the second the typical dose of radiation used for thyroid cancer treatment.

After three years, according to STAT News, there was no difference in the two groups when it came to needing new treatments, relapses, or abnormal biological markers. The study subjects will continue to be monitored, but Leboulleux does not expect to see any changes.

This study provides the first hard evidence that postoperative radiation is likely useless in low-risk thyroid cancer, says Cooper. The study further bolsters the current recommendation to skip radioactive iodine in treating low-risk thyroid cancer patients.

That should help doctors and patients feel more comfortable about not having radiation after thyroid surgery.

“Radiation is just one more worry for a patient,” said Leboulleux. “Once you know you don’t need it, I don’t think you should receive it.”

Radioactive iodine is still prescribed for high-risk thyroid cancer that has spread throughout the body. It’s still questionable whether the treatment is of benefit for intermediate-risk patients, but that is something Leboulleux plans to investigate next.