Panel Reclassifies Thyroid Tumor to Reduce Overdiagnosis of Cancer and Unnecessary Aggressive Treatment
Commentary by Lead Investigator Yuri Nikiforov, MD, PhD and John C. Morris, III, MD
An international panel of experts recommends reclassifying noninvasive encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) as “noninvasive follicular thyroid neoplasm with papillary-like nuclear features” (NIFTP). The panel expects the name change to reduce the psychological and medical consequences of a cancer diagnosis in patients with these low-risk tumors.
The American Thyroid Association has not yet officially endorsed the reclassification, but supports the idea of using less treatment for low-risk lesions such as EFVPTC and reserving more aggressive treatment for higher-risk lesions, explained John C. Morris, III, MD, Professor of Medicine and Endocrinology at Mayo Clinic Rochester, and President Elect of the American Thyroid Association.
Dr. Morris noted that the panel’s paper was based on 109 patients, and that the ATA is “waiting for additional data, additional independent support of the findings of this paper.”
EFVPTC is Noninvasive and Nonprogressive
Diagnosis of EFVPTC has increased in incidence by an estimated two- to three-fold over the past 20 to 30 years and currently accounts for 10% to 20% of all thyroid cancers diagnosed in Europe and North America, the panel noted. Although studies have shown EFVPTC is noninvasive, has indolent behavior, and is genetically distinct from infiltrative tumor types, the panel wrote.
At the recommendation of a National Cancer Institute supported conference, the panel sought to revise the terminology and to see if the classification “cancer” could be dropped from its name.
Panel Reviewed 109 Cases of Noninvasive EFVPTC
The panelists—24 experienced thyroid pathologists from 7 countries—independently reviewed 268 tumor samples diagnosed as EFVPTC from 13 institutions. The experts established diagnostic criteria, including cellular features, tumor invasion and other factors. In a group of more than 109 cases of noninvasive EFVPTC, there were no recurrences or other manifestations of the disease at a median follow-up of 13 years, the panel found.
Based on these findings, the panel suggested renaming EFVPTC as "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" or NIFTP, indicating that it need not be treated with radioiodine or other aggressive approaches.
The panel also proposed a 3-point scoring scheme based on nuclear features that showed high sensitivity (98.7%) and specificity (90.1%). The scoring scheme had an overall classification accuracy of 94.3%. The diagnostic criteria were based on the following nuclear features:
- Encapsulation or clear demarcation (ie, thick, thin, or partial capsule or well circumscribed with a clear demarcation from adjacent thyroid tissue)
- Follicular growth pattern:
- <1% Papillae
- No psammoma bodies
- <30% Solid/trabecular/insular growth pattern
- Nuclear score of 2-3
- No vascular or capsular invasion
- No tumor necrosis
- No high mitotic activity
“We determined that if NIFTP is carefully diagnosed, the tumor’s recurrence rate is extremely low, likely less than 1% within the first 15 years,” Yuri Nikiforov, MD, PhD said. “The cost of treating thyroid cancer in 2013 was estimated to exceed $1.6 billion in the U.S. Not only does the reclassification eliminate the psychological impact of the diagnosis of ‘cancer,’ it reduces the likelihood of complications of total thyroid removal, and the overall cost of health care.” Dr. Nikiforov is Vice-Chair for Molecular Pathology and Director, Division of Molecular and Genomic Pathology at the University of Pittsburgh Medical Center.
“To my knowledge, this is the first time in the modern era a type of cancer is being reclassified as a non-cancer,” explained senior investigator Yuri Nikiforov, MD, PhD, in a news release. “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,” said Dr. Nikiforov.
While most experienced physicians have been treating EFVPTC as a low-risk lesion (ie, not with radioiodine or other aggressive treatments), the name change will have the biggest impact for less experienced physicians or those who less frequently see patients with thyroid cancer.
“For those less experienced physicians, perhaps by removing the word ‘cancer’ from the name will make them less likely to pursue or recommend additional surgery or radioiodine treatment in cases where these treatments clearly don’t offer any benefit because the risk is so very low.”
Impact on Patients
For some patients, the name change can have a psychological benefit, Dr. Morris added.
“All patients are all different. Some patients understand when we say, ‘It is a very low-risk cancer, and it has been cured by the surgery you’ve already had. You don’t need any other treatment.’ Some patients are quite happy with that and not troubled,” Dr. Morris explained.
“But other patients, when they hear the word ‘cancer,’ can become quite alarmed and have trouble getting beyond that, even with the reassurance of their physicians. For these patients, removing the word ‘cancer’ for could have some significant psychological benefit,” Dr. Morris said.
“I think it is important for physicians and patients to understand that there is still surgery involved in the management of these tumors,” Dr. Morris said. “This is not a diagnosis made from a needle biopsy. This is a nodule that probably would be called ‘suspicious’ on needle biopsy or possibly positive for papillary cancer on biopsy, and the patient would require surgery to remove it.
“It is only after the tumor is surgically removed that the diagnosis can be made, whether with the old or new terminology,” Dr. Morris said, reiterating that management does not change despite the proposed name change.
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May 5, 2016