Are Fukushima Child Thyroid Cases a Matter of Over-diagnosis?

Are Fukushima Child Thyroid Cases a Matter of Over-diagnosis?

(Updated 3/14/16)

December 17, 2015

The improvements in medical diagnostic technology over the past 30 years have been considerable. The sensitivity of these procedures has improved dramatically. Our inquiry concerns state-of-the-art ultrasound detection technology with respect to tiny thyroid anomalies (cysts and nodules) are detectible today, but were almost impossible to find three decades ago. As a result, the rate thyroid cancer diagnosis has increased significantly through-out the world. According to the Cancer Incidence in Five Continents database maintained by International Agency for Research on Cancer, since 1993 the rate of thyroid-cancer diagnosis has more than doubled in France, Italy, Croatia, the Czech Republic, Israel, China, Australia, Canada, and the United States. However, there has been no increase in the rate of thyroid cancer deaths over the same period. This leads to a startling possibility.

Over the past 20 years, an unprecedented controversy has worked its way into the thyroid cancer realm – is the increased rate of thyroid cancer incidence due to over-diagnosis? And, if it is, what does this mean relative to the child thyroid cancer situation in Fukushima Prefecture?

My inquiry into this began with a social media contact asking me if Fukushima’s child thyroid cancers might not be “incidentalomas”. The term was new to me. I found that incidentalomas are cancerous growths found “incidentally” while looking for something elsewhere. An example could be a diagnostic procedure investigating a lump in someone’s throat and small nodules are incidentally discovered with the thyroid gland.

However, the thyroid anomalies with Fukushima children were not found in this fashion. The modern ultrasound and fine-needle aspiration biopsy procedures used by Fukushima Medical University were concerned only with thyroid screening. The detected nodules and cysts were precisely what the screenings were supposed to find. Thus, the Fukushima anomalies cannot be termed incidental. However, my research did chance upon something that seemed to specifically relate to the Fukushima child thyroid situation – possible over-diagnosis resulting from “indolent” thyroid carcinomas.

Indolent thyroid carcinomas are small papillary tumors, which studies have shown are very slow-growing and highly unlikely to ever cause full-blown cancers, much less death. (1) An elevated rate of papillary lesions (i.e. cysts and nodules) are being diagnosed because of advances in high-tech imaging technologies, such as ultrasound, computed tomography, and magnetic resonance imaging, which can detect thyroid anomalies as small as 2 millimeters. Thirty years ago, this was not the case.

These state-of-the-art investigative tools have resulted in an unprecedented increase in thyroid cancer diagnoses around the world. Dr. Joseph Mercola reports, “In the US, the rate of thyroid cancer has doubled since 1994.” (1) In South Korea, it has become the most commonly diagnosed type of cancer, having increased 15-fold in the past 20 years! (2) What’s more, almost all new thyroid cancers – 90 percent – qualify to be judged indolent! (1)

Are these tiny indolent thyroid anomalies really worthy of medical concern? Should invasive surgery be used to remove the thyroids? Or not? Dr. H. Gilbert Welch of Dartmouth, says, “An epidemic of real disease would be expected to produce a dramatic rise in the number of deaths from disease. Instead we see an epidemic of diagnosis; a dramatic rise in diagnosis and no change in death [rates].” (3)

Generally speaking, most thyroid cancer diagnoses seem to be particularly indolent. Upon post-death autopsy, as many as a third of the deceased have been found to have tiny thyroid cancers that went undetected in their lifetime. Dr. R. Michael Tuttle, MD, of the Memorial Sloan Kettering Cancer Center, says, “We are clearly over-diagnosing Thyroid Cancer….particularly of the sub-centimeter papillary micro carcinomas. The vast majority of these thyroid nodules would have stayed small for 100 years without any intervention. There is no question that overuse of ultrasound and fine-needle aspiration (FNA) biopsy is leading to this over-diagnosis.” (4)

It is important to note that a significant fraction of FNA biopsies, no matter how small the anomaly might be, test out as cancerous. But, the statistics seem to suggest that these sub-centimeter nodules are indolent, and not aggressive (growing). Dr. Tuttle explains why most of these findings are treated as aggressive, regardless, , “It is really hard to tell someone that they have cancer, prove it, and then tell them not to do anything about it.” The common notion is that there is no safe level of cancer - if one cancer cell occurs in the body, there is a risk of dying of a full-blown cancer disease. The possibility of dying of cancer is perhaps the greatest medical fear ingrained in the general public.

So, why not just remove the apparently cancerous thyroid, and be done with it? That seems to be the rational used almost universally, including Fukushima Prefecture.

There are risks associated with thyroid removal and subsequent hormone treatments (for life) that may-well carry greater risks than if the indolent nodules were left in situ. A Duke University research report says, “These over-diagnosis cases represent an important potential harm of screening because they incur additional cost, anxiety, and morbidity associated with cancer treatment.” (5) This elevated risk with indolent carcinoma surgery is significant enough that National Comprehensive Cancer Network (NCCN) does not recommend biopsy of thyroid nodules that are less than 1 cm. (6) However, most clinical physicians essentially ignore the NCCN recommendation. Instead, Dr. Tuttle recommends clinicians resist running the FNA biopsy on small (<1cm) nodules, and instead recommend that a subsequent diagnostic procedure take place in six months to see if it has grown. If it has not grown, then proscribe another follow-up, and perhaps even another, until it is likely the anomaly will never grow into full-blown thyroid cancer.

Dr. Tuttle echoes a question that is not uncommon among thyroid cancer experts, “So we are beginning to ask; is cancer even the right thing to call these small nodules, because cancer is such a powerful word.” Some call for a complete overhaul of the definition of cancer, in general, because the issue is not specific to just thyroid cancers. It’s quickly becoming widespread. However, cooler heads have written in the Journal of the American Medical Association that these very small thyroid anomalies should be re-named as Indolent Lesions of Epithelial Origin, acronym ILEO. (7,8)

At this point, we can understand why the ILEO issue is directly relevant to what has happened in Fukushima Prefecture. Of the roughly 400,000 children screened by Fukushima Medical University, some 41% were given either an A2 or B diagnosis. A2 designates detectible thyroid anomalies of less than 5 millimeters for nodules and/or <20mm for cysts. (9,10) To date, 115 children had nodules greater than 5mm and/or cysts greater than 20mm, were designated in the “B” category, and suffered surgical removal. Of the 39 most-recent discoveries, at least fifteen have experienced the radical removal.

Several new questions emerge. First, how many of the Fukushima thyroid anomalies judged worthy of surgery were actually below the ILEO threshold of 1cm? The Fukushima Medical university data only shows the numbers that were found to be greater than a half-centimeter (5 millimeters). How many were less than one centimeter? I think we would all like to know the answer to that.

Next, why hasn’t the possibility of non-aggressive, essentially harmless indolent carcinomas been explained to the frightened parents of these Fukushima children? It is unthinkable that the Fukushima Medical University staff has never heard of this. However, they might fear possible allegations of “cover-up”, rampant on the internet and in the Japanese Press relative to non-frightening science associated with Fukushima. How can they say they discovered something that tests to be cancerous, then tell the frightened parents it’s nothing to worry about? That would sound worthy of distrust. However, if the risk of surgery and subsequent therapy is worse than the risk posed by these tiny cysts and nodules, it seems the screening team should at least give the parents of these children the facts and let them decide on which path to follow.

Lastly, why hasn’t the world’s clinical thyroid research community brought pressure on the Fukushima team to at least mention the possibility that most, if not all of the Fukushima child thyroid cancers were/are indolent and likely not of mortal threat? This final question may well be the most troubling.

(3/14/16) - An American oncologist also says the Fukushima child thyroid cancers are a case of over-diagnosis. David Gorski, MD & PhD, has written Op-Ed articles about the modern medical overdiagnosis issue for several years. In his latest report, he states that when searching for a prime example of overdiagnosis, and subsequent unnecessary invasive surgery, “…it’s hard to find a better example of this than the aftermath of the March 2011 meltdowns at the Fukushima Daiichi Nuclear Plant…” Gorski then asserts, “There is almost certainly no thyroid cancer epidemic in Fukushima [Prefecture].” His rebuttal of the widely-broadcast claim of such an epidemic by our maverick Epidemiologist at Okayama University is detailed and pulls no punches.


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