Noninvasive papillary thyroid carcinoma renamed to remove cancer label

Noninvasive thyroid tumors currently diagnosed as encapsulated follicular variant of papillary thyroid carcinoma had a very low probability of adverse outcomes and should no longer be classified as a cancer, according to researchers of a retrospective study.

The researchers suggested that the condition should be renamed “noninvasive follicular thyroid neoplasm with papillary-like nuclear features,” or NIFPT.

A body of evidence suggests that the encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) is largely indolent, according to study background. However, patients with the condition currently are treated as having conventional thyroid cancer.

“A large population of patients — over 10,000 in the United States alone — are diagnosed with this disease,” Yuri E. Nikiforov, MD, PhD, vice-chair for molecular pathology and director of the division of molecular and genomic pathology at University of Pittsburgh Medical Center, told HemOnc Today. “They experience the psychological distress of being labeled as having cancer.”

Nikiforov and colleagues of an Endocrine Pathology Society working group conducted an international, multidisciplinary retrospective study of 109 patients with noninvasive EFVPTC (mean age, 45.9 years; range, 21-81; 83% women) and 101 patients with invasive EFVPTC (mean age, 42.8 years; range, 8-78; 70% female).

Twenty-four working group pathologists independently reviewed patients’ digitized histologic slides — collected at 13 sites in five countries — and provided their diagnosis in accordance with existing criteria. Other members of the working group — which, in addition to the pathologists, included two endocrinologists, one surgeon, one psychiatrist, one molecular pathologist, a biostatistician and a survivor/patient advocate — met to review related molecular and clinical outcome information to discuss new nomenclature.

Key study outcomes included the frequency of adverse outcomes, which included death from disease, distant or locoregional metastases, and structural or biochemical recurrence.

The mean follow-up was 14.4 years (range, 10-26) for patients with noninvasive EFVPTC and 5.6 years (1-18) for patients with invasive EFVPTC.

All patients with noninvasive EFVPTC remained alive at the end of follow-up, with no evidence of disease. Sixty-seven of these patients underwent lobectomy alone; the remaining 42 underwent total thyroidectomy. No patient in this cohort received radioactive iodine ablation.

In contrast, 12 patients with invasive EFVPTC experienced an adverse event, including two deaths and five cases of distant metastases. Other adverse outcomes included lymph node recurrence (n = 1), persistent disease (n = 1) and detectable serum thyroglobulin (n = 5).

Eighty-six patients in this cohort underwent total thyroidectomy and 85 received radioactive iodine ablation.

Based on these data, the researchers endorsed a nomenclature revision for noninvasive EFVPTC.

The researchers designed and validated a diagnostic nuclear scoring system for NIFPT, consisting of reviewing a lesion’s size and shape, nuclear membrane irregularities and chromatin characteristics.

The scoring system yielded a sensitivity of 98.6% (95% CI, 96.3-99.4), a specificity of 90.1% (95% CI, 86-93.1) and overall classification accuracy of 94.3% (95% CI, 92.1-96) for NIFPT.

Researchers estimated that renaming noninvasive EFVPTC as NIFPT would affect 45,000 patients worldwide yearly.

“Many patients diagnosed with noninvasive EFVPTC undergo additional surgery and radioactive iodine ablation,” Nikiforov said. “They have to come for checkups every 6 months or 12 months for the rest of their lives. We know that these are not necessary now.”

The change in nomenclature makes medical, financial and psychosocial sense, Kepal N. Patel, MD, director of the division of endocrine surgery at NYU Langone Medical Center, wrote in an accompanying editorial.

“The reclassification of noninvasive EFVPTC to NIFPT is a timely and appropriate change,” Patel wrote. “It highlights the true biologic nature of this tumor, lessens the emotional and psychological burden associated with the term cancer, and results in increased cost savings by potentially decreasing overtreatment that exposes patients to unnecessary risks.” – by Cameron Kelsall

For more information:

Yuri E. Nikiforov, MD, PhD, can be reached at nikiforovye@upmc.edu.

Disclosure: Nikiforov reports a consultant role with Quest Diagnostics. Please see the full study for a list of the other researchers’ relevant financial disclosures. Patel reports no relevant financial disclosures.