What's in a Name: Expert Re-Examines Papillary Thyroid Carcinoma's Classification as Cancer


Encapsulated follicular variant of papillary thyroid cancer may actually not be cancer at all, according to Yuri E. Nikiforov.

The word “cancer” undoubtedly triggers a negative psychological effect when uttered to patients. However, according to a recent study led by Yuri E. Nikiforov, M.D, Ph.D, 10 to 20 percent of patients diagnosed with thyroid cancer may not actually have cancer.

Nikiforov, the vice chair of the Department of Pathology at University of Pittsburgh Medical Center, presented his findings at the 86th Annual Meeting of the American Thyroid Association, claiming that encapsulated follicular variant of papillary thyroid cancer (EFVPTC) should not be classified as a type of cancer.

What are you presenting on here at the meeting?

CURE sat down with Nikiforov to further discuss his study.I'm presenting the results of a study that we recently published in JAMA Oncology which allowed us to reclassify one type of thyroid cancer as non-cancer. We know that there is a certain type of thyroid cancer that was known as cancer for many years that is actually very indolent and doesn’t often hurt patients.

When we analyzed a number of large series of patients and followed them for many years, we concluded that most of these patients really live a normal life and never get any adverse outcomes from the cancer. So as a result, it's being suggested to remove the term "cancer" from the name of this tumor and reclassify this tumor as non-invasive follicular tumor — NIFTP. So patients will no longer be labeled with the term "cancer."

How did you come to realize that it might not actually be cancer? What characteristics make up cancer?

Until recently, this type of tumor was known as encapsulated follicular papillary cancer. We have estimated that approximately 10 to 20 percent of all patients are diagnosed with this, so this reclassification will affect approximately 10,000 people every year in the United States.

Cancer is a disease that hurts patients. It has a high risk of coming back, eventually to kill the patient. This is the clinical definition of cancer. What was interesting about this disease is that it looks like cancer on the microscope — admittedly it looked like a low-grade cancer — and it has the histopathological features that are frequently seen in cancer. But, nevertheless, clinically, it would not hurt the patient.

How is the disease currently being treated?

This diagnosis can be established when only one lobe of the thyroid is removed. Patients have a nodule and they can suspect, based on clinical or molecular parameters, that this is actually likely to be NIFTP. In this situation, instead of patients undergoing total thyroid removal, only one lobe of the thyroid is removed. When we confirm this diagnosis, patients don't have to have the completion of thyroidectomy — they don't have treatment that would be needed if the patient got a diagnosis of cancer.

What if the patient is never diagnosed? Would they be fine, or would it eventually develop into something else?

In this study, we actually looked at two groups of patients, including those who have very similar histopathological features and clinical features but who didn't have invasion through the capsule. We also watched a group of patients with very similar tumors who also invaded through the capsule. In the second group, 10 percent of patients had adverse outcomes and 2 percent of patients died of the disease. So, we believe that a significant proportion of these tumors, if left untreated, will progress to the clinically full-blown cancer. So the nodules have to be removed, but you don't have to do extensive surgery.

To give you analogy, many years ago, breast cancer was treated by total mastectomy, sometimes double mastectomy. Now it's treated with very segmented lobectomy. This is prototypical — you treat very locally, and not many other treatments are needed.

Can this be compared to ductal carcinoma in situ (DCIS) in breast cancer?

Yes. In many different cancer types, all of our knowledge of cancer tells us that tumors progress from benign to malignant in several stages.

In the thyroid field, for all these years, the disease was either benign or malignant, which we know that biologically and clinically it doesn't make sense. These lesions exactly feed into this category of progression, of indeterminate lesions, of rare cancer lesions between benign and malignant.

What are the next steps in this research?

We need, of course, to follow these patients who have had very limited surgery for some time to be really sure, beyond any doubt, that this indeed is a low-risk tumor that doesn't need additional treatment. We also need to continue studies to define the genetic profile even more and be able, before surgery, to say with a high degree of confidence that this is not really a cancer.

On a broader scale, for the field of oncology in general, we really hope that this example will lead the way for other cancers to be reclassified by working groups. This is not a simple process. It has to be data-driven. It has to be an international, multi-disciplinary approach. Then, based on the data, we can reclassify, because the word "cancer" by itself brings a lot stress to patients. Using it very broadly without really proper limitation to the tumors that can really hurt patients — that would probably be inappropriate.

What can the field of oncology take away from all of this?

I would say that people need to be aware. There is a certain category of thyroid cancer that no longer carries a diagnosis of cancer. If a patient comes with a diagnosis of encapsulated follicular of papillary carcinoma, they should request the histological slice to be reviewed, because this diagnosis can be changed. This will have significant implications for patients. They don't need to have a completion of thyroidectomy, they don't need to have radiation, they don't need to have yearly checkups and they won't have the stigma of cancer that unfortunately still exists.

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