An international panel of doctors has agreed that a type of thyroid tumor that was classified as cancer will no longer be considered as cancer to show that the condition is non-invasive and has low risk of recurrence.
The decision, which officially downgraded and renamed the condition, is expected to impact about 10,000 thyroid cancer patients in the U.S. per year, as it is set to reduce the psychological and medical consequences linked with cancer diagnosis.
Thousands of patients, for instance, will no longer have their thyroid removed and will be spared from treatment with radioactive iodine and a lifetime of regular checkups.
The reclassified tumor is marked by a small lump in the thyroid enveloped by a capsule of fibrous tissue. Although the nucleus appears like cancer, the cells have not broken out of the capsule, which means that a surgery to remove the entire thyroid and a treatment with radioactive iodine are not just unnecessary but also harmful.
"This phenomenon is known as overdiagnosis," said Yuri Nikiforov, from University of Pittsburgh School of Medicine, who noted this may be the first instance in the modern era that a type of cancer was reclassified
"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."
Nikiforov and colleagues looked at a hundred cancer cases involving patients who had tumors that were encapsulated within fibrous capsules and those whose tumors had broken out.
Using current criteria, each of these tumors would be classified as cancer. By tracking the patients for at least 10 years, however, they found that those with the encapsulated tumors did not have evidence of cancer after a decade despite not receiving treatment.
"They do not need a thyroidectomy. They do not need radiotherapy. They do not need to be followed up every six months," Nikiforov said.
Some of the patients whose tumors have broken out, however, had complications, which even resulted in death from thyroid cancer despite having received treatment.
The panel has now renamed the reclassified tumor. From "encapsulated follicular variant of papillary thyroid carcinoma," or EFVPTC, it would be called "noninvasive follicular thyroid neoplasm with papillary-like nuclear features," or NIFTP.
"Thyroid tumors currently diagnosed as noninvasive EFVPTC have a very low risk of adverse outcome and should be termed NIFTP" Nikiforov and colleagues reported in JAMA Oncology on April 14. "This reclassification will affect a large population of patients worldwide and result in a significant reduction in psychological and clinical consequences associated with the diagnosis of cancer."
