Certain Thyroid Tumors Reclassified As Non-Cancerous

A new study says non-invasive thyroid tumors do not need intensive cancer treatment.

Thousands of people who woke up cancer patients on Wednesday no longer were by Thursday.

That’s because a large cohort of doctors, including several from Boston hospitals, have reclassified a specific type of thyroid tumor as non-cancerous. Until Thursday, the tumors—a subtype that remain totally enclosed within tissue—were considered cancer; now, however, they’re to be called a “noninvasive follicular thyroid neoplasm with papillary-like nuclear features.”

The name hardly rolls of the tongue, but removing the cancer designation will change thousands of patients’ courses of treatment, and ease the psychological burden associated with receiving a cancer diagnosis. Indeed, since the tumors are no longer considered cancerous, patients who have them will not have to swallow radioactive iodine, a common treatment for thyroid cancer that, while minimally invasive, can come with its own drawbacks.

“It’s basically swallowing a hefty dose of a radioactive isotope that, otherwise, you would have tried to stay away from,” says Jochen Lorch, director of the Thyroid Center at Dana-Farber Cancer Institute. “There is a small but real risk of developing either leukemia, or something that resembles leukemia, as a result of that dose of radioactivity. That risk is real, so it’s real progress if people don’t have to do that.”

How, though, can something that was considered a cancer magically become something less? The doctors involved in the study, published Thursday in JAMA Oncology, retroactively reviewed the treatment results of 268 patients with thyroid tumors. They found that, of the roughly 100 patients with non-invasive tumors, there were no recurrences within a median of 13 years, suggesting that totally encapsulated tumors do not need aggressive treatment.

“These things basically looked like thyroid cancer under the microscope, but they didn’t behave like cancer at all,” Lorch, who was not involved in the study, explains. “[Now] there will be people out there, every day, who will not be treated with radioactive iodine unnecessarily.”

Though Lorch notes that thyroid cancer is something of a unique case—few other types of disease see totally encapsulated tumors, and radioactive iodine is used only to treat thyroid cancer—other experts say the reclassification may have ramifications across oncology.

“To my knowledge, this is the first time in the modern era a type of cancer is being reclassified as a non-cancer,” Senior Investigator Yuri Nikiforov said in a statement. “I hope that it will set an example for other expert groups to address nomenclature of various cancer types that have indolent behavior to prevent inappropriate and costly treatment.”