Why NIFTP is Nifty

On April 14, 2016 JAMA Oncology published a landmark article entitled Nomenclature Revision for Encapsulated Follicular Variant of Papillary Thyroid Carcinoma: A Paradigm Shift to Reduce Overtreatment of Indolent Tumors (http://oncology.jamanetwork.com/article.aspx?articleid=2513250).  The Encapsulated Follicular Variant of Papillary Thyroid Carcinoma (EFVPTC) was initially defined by Lindsay during the 1950’s and became well recognized during the 1970s after a paper about it was published by Chen and Rosai (1).   EFVPTC was classified as a papillary thyroid carcinoma due to these tumors sharing nuclear features with that type of thyroid cancer. Previous to that, it was classified as a type of follicular carcinoma because it generally lacked papillary structures. The new paper in JAMA proposed that EFVPTC, when noninvasive and when meeting certain other criteria, should be reclassified as a benign tumor called NIFTP.

Since the 1970s, many articles were published about difficulties in diagnosing the encapsulated follicular variant when the tumor did not display invasive properties.  There were disputes about the  necessary criteria and thresholds for the diagnosis to be made, but also reports about poor inter-observer agreement between expert pathologists on whether specific specimens were benign or malignant.  Efforts to resolve these problems have never been successful.  As a result, a patient could receive a benign or malignant diagnosis on the same tumor, depending upon which pathologist was consulted.  There were also published articles stating that the threshold for diagnosis was becoming lower and lower because pathologists feared litigation from patients in the event of a missed cancer (2).

Thus, it is disconcerting for a patient to learn that the diagnosis of non-invasive EFVPTC has historically been based solely on expert opinion rather than on a scientific study of a series of such tumors. The method of arriving at tumor classifications via a system of consensus among experts means that power dynamics, processes, and methodologies that are not transparent to lay people will often dictate the lines between” benign” and “malignant”.  In this opaque climate, it can take decades for any meaningful actions  leading to  revisions in classifications to take place.  In the meantime, thousands of individual patients could be diagnosed with cancer and subjected to unnecessary treatments and other negative effects.  The facts surrounding the establishment noninvasive EFVPTC also call into  question whether it could be claimed that there was ever an objective basis for the “standard of care” that’s often  invoked by doctors in justification of  interventions  that patients have received.

A piece about NIFTP, by Gina Kolata, appeared in the New York Times last week (http://www.nytimes.com/2016/04/15/health/thyroid-tumor-cancer-reclassification.html). It detailed the process by which the reclassification proposal was initiated by pathologist Yuri Nikiforov of the University of Pittsburgh.  According to the article, Nikiforov became fed up with the “standard of care” for noninvasive EVPTC when he was told by a surgeon colleague that a nineteen year old patient with the tumor needed a completion thyroidectomy and radioactive iodine treatment.

Nikiforov lead an approximately two year investigation into EFVPTC cases involving 24 pathologists from seven countries.  The results of their study showed a zero recurrence rate for their series of the non-invasive type over a median followup of thirteen years.

In order to undo “expert opinion” arrived at  by dubious methods, a meticulous process had to be implemented by someone who had the courage to do the right thing.  Otherwise, what once was called noninvasive EFVPTC may have continued its trajectory as a “cancer” for another decade.

That’s why NIFTP is big news for many thousands of patients who have been diagnosed with thyroid cancer.

Notes:

  1. http://journals.lww.com/ajsp/abstract/1977/06000/follicular_variant_of_thyroid_papillary_carcinoma_.3.aspx
  2. http://www.kakudok.jp/pdf/object/2011ejkakudo_new.pdf

 

 

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