Neuroendocrine Tumours – benign vs malignant

Kunz His belief these tumors did not metastisize

OPINION:

One of the most controversial aspects of Neuroendocrine Tumours (NETs) is the ‘benign vs malignant’ question.  It’s been widely debated and it frequently patrols the various patient forums and other social media platforms. It raises emotions and it triggers many responses ….. at least from those willing to engage in the conversation. At best, this issue can cause confusion, at worst, it might contradict what new patients have been told by their physicians (….or not been told). I don’t believe it’s an exact science and can be challenging for a NET specialist let alone a doctor who is not familiar with the disease.

NANETS Guidance talks about the ‘…heterogeneous clinical presentations and varying degrees of aggressiveness‘ and ‘…there are many aspects to the treatment of neuroendocrine tumours that remain unclear and controversial‘.  I’m sure the ‘benign vs malignant’ issue plays a part in these statements.

In another example, ENETS Guidance discusses (e.g.) Small Intestine Tumours (Si-NETs) stating that they ‘derive from serotonin-producing enterochromaffin cells. The biology of these tumors is different from other NENs of the digestive tract, characterized by a low proliferation rate [the vast majority are grade 1 (G1) and G2], they are often indolent’.  However, they then go on to say that ‘Si-NETs are often discovered at an advanced disease stage – regional disease (36%) and distant metastasis (48%) are present‘.  It follows that the term ‘indolent‘ does not mean they are not dangerous and can be ignored and written off as ‘benign’. This presents a huge challenge to physicians when deciding whether to cut or not to cut.

Definitions

To fully understand this issue, I studied some basic (but very widely accepted) definitions of cancer.  I also need to bring the ‘C’ word into the equation (Carcinoid), because the history of these tumours is frequently where a lot of the confusion lies.  The use of the out of date term ‘Carcinoid’ exacerbates the issue given that it decodes to ‘carcinoma like‘ which infers it is not a proper cancer.  See more below.

Let’s look at these definitions provided by the National Cancer Institute.  Please note I could have selected a number of organisations but in general, they all tend to agree with these definitions give or take a few words. These definitions help with understanding as there can be an associated ‘tumour’ vs ‘cancer’ debate too.

Cancer – Cancer is the name given to a collection of related diseases. In all types of cancer, some of the body’s cells begin to divide without stopping and spread into surrounding tissues. There are more than 100 types of cancer which are usually named for the organs or tissues where the cancers form.  However, they also may be described by the type of cell that formed them.

Author’s note: The last sentence is important for Neuroendocrine Tumour awareness (i.e. Neuroendocrine Tumour of the Pancreas rather than Pancreatic Cancer).

Carcinoma – Carcinomas are the most common grouping of cancer types. They are formed by epithelial cells, which are the cells that cover the inside and outside surfaces of the body. There are many types of epithelial cells, which often have a column-like shape when viewed under a microscope.

Author’s note: By definition, Carcinomas are malignant, i.e. they are cancers. High Grade (Grade 3) poorly differentiated “NETs” are deemed to be a ‘Carcinoma’ according to the most recent World Health Organisation (WHO) classification of Neuroendocrine Tumours (2017) and ENETS 2016 Guidance. You will have heard of some of the types of Carcinoma such as ‘Adenocarcinoma’ (incidentally, the term ‘Adeno’ simply means ‘gland’). It follows that Grade 3 Neuroendocrine Carcinomas are beyond the scope of this discussion.

Malignant – Cancerous. Malignant cells can invade and destroy nearby tissue and spread to other parts of the body.

Benign – Not cancerous. Benign tumors may grow larger but do not spread to other parts of the body.

Author’s Note: This is a key definition because there are people out there who think that low grade NETs are not cancer. 

Tumour (Tumor) – An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called Neoplasm.

Author’s Note: Neoplasm is an interesting term as this is what is frequently used by ENETS and NANETS in their technical documentation, sometimes to cover all Neuroendocrine types of cancer (Tumor and Carcinoma). It follows that a malignant tumour is Cancer. The term “Malignant Neuroendocrine Tumour” is the same as saying “Neuroendocrine Cancer”

Neuroendocrine Tumours – Benign or Malignant?

Definitions out of the way, I have studied the ENETSUKINETS and NANETS guidance both of which are based on internationally recognised classification schemes (i.e. the World Health Organisation (WHO)).

In older versions of the WHO classification schemes (1980 and 2000), the words ‘benign’ and ‘uncertain behaviour’ were used for Grades 1 and 2. However, the 2010 edition, the classification is fundamentally different (as is the recent 2017 publication).  Firstly, it separated out grade and stage for the first time (stage would now be covered by internationally accepted staging systems such as TNM – Tumour, (Lymph) Nodes, Metastasis). Additionally, and this is key to the benign vs malignant discussion, the WHO 2010 classification is based on the concept that all NETs have malignant potential.  Here’s a quote from the UKINETS 2011 Guidelines (Ramage, Caplin, Meyer, Grossman, et al).

Tumours should be classified according to the WHO 2010 classification (Bosman FT, Carneiro F, Hruban RH, et al. WHO Classification of Tumours of the Digestive System. Lyon: IARC, 2010). This classification is fundamentally different from the WHO 2000 classification scheme, as it no longer combines stage related information with the two-tiered system of well and poorly differentiated NETs. The WHO 2010 classification is based on the concept that all NETs have malignant potential, and has therefore abandoned the division into benign and malignant NETs and tumours of uncertain malignant potential.

The guidance in 2017 WHO reinforces this statement to include endocrine organs, including the pancreas and adrenal glands.

The C Word (Carcinoid) – part of the problem?

History lesson – Carcinoid tumours were first identified as a specific, distinct type of growth in the mid-1800’s, and the name “karzinoide” was first applied in 1907 by German pathlogist Siegfried Oberndorfer in Europe in an attempt to designate these tumors as midway between carcinomas (cancers) and adenomas (benign tumors).

The word ‘Carcinoid’ originates from the term ‘Carcinoma-like’.  ‘CARCIN’ is a truncation of Carcinoma. ‘OID’ is a suffix used in medical parlance meaning ‘resembling’ or ‘like’.  This is why many people think that Carcinoid is not a proper cancer.

The situation is made even more confusing by those who use the term “Carcinoid and Neuroendocrine Tumors” inferring that it is a separate disease from the widely accepted and correct term ‘Neuroendocrine Tumor’ or Neuroendocrine Neoplasm.  A separate discussion on this subject can be found in this post here. I encourage you to stop using the term ‘Carcinoid’ which is just perpetuating the problem. 

Kunz His belief these tumors did not metastisize

How are NETs Classified?

If you read any NET support website it will normally begin by stating that Neuroendocrine Tumours constitute a heterogeneous group of tumours. This means they are a wide-ranging group of different types of tumours.  However, the latest WHO classification scheme uses the terms ‘Neuroendocrine Tumour’ for well differentiated Grade 1 (low-grade), Grade 2 (Intermediate Grade) and Grade 3 (High Grade) NET; and ‘Neuroendocrine Carcinoma’ for Grade 3 (High Grade) poorly differentiated tumours. They also use the term ‘Neoplasm’ to encompass all types of NET and NEC. So Grade 1 is a low-grade malignancy and so on (i.e any grade of NET is a malignant tumour).  You may benefit from reading my blog article on Staging and Grading of NETs as this is also a poorly understood area.

Can some Tumours be Benign?

By any accepted definition of cancer terms, a tumour can be non-cancerous (benign) or cancerous (malignant).  This is correct for any cancer type. For example, the word is used in the 2016 version of Inter Science Institute publication on Neuroendocrine Tumors, a document I frequently reference in my blog.  For example, I’ve seen statements such as “These tumors are most commonly benign (90%)” in relation to Insulinoma (a type of Pancreatic NET or pNET). Ditto for Pheochromocytoma (an adrenal gland NET).  Adrenal and Pituitary ‘adenomas’ are by definition benign (adenoma is the benign version of Adenocarcinoma).  And I note that there is a ‘benign’ code option for every single NET listed in the WHO International Classification of Diseases (ICD) system.

The ‘BUT’ is this – all WHO classification systems are based on the concept that all NETs have malignant potential.  The WHO 2017 classification update confirmed this thinking by adding endocrine organs including the pancreas and adrenal glands.

don't worry it's benign widescreen

Can Tumours be Malignant or become Malignant?

Using the definition above, if a tumour invades and destroy nearby tissue and spread to other parts of the body, then it’s malignant (i.e  Cancer). However, there’s a reason why the WHO declared in 2010 that all NETs have malignant potential (as amplified in WHO 2017). It may not happen or it may happen slowly over time but as Dr Richard Warner says, “they don’t all fulfill their malignant potential, but they all have that possible outcome”.  Thus why ongoing surveillance is important after any diagnosis of Neuroendocrine Tumour of any grade or at any stage.  Dr Lowell Anthony, a NET Specialist from the University of Kentucky explains this much better than I can – CLICK HERE to hear his two-minute video clip.

Summary

This was a difficult piece of research. I do believe there are scenarios where NETs will be benign and probably never cause the person any real harm (e.g. many are found on autopsies). I  suspect this is the same for many cancers. However, based on the above text and the stories of people who have presented for a second time but with metastatic disease, use of the word ‘benign’ is probably best used with great care.

I would certainly (at least) raise an eyebrow if someone said to anyone with any NET tumour, “you don’t need any treatment or surveillance for a NET”; or “it has been cured and no further treatment or surveillance is required”.  Particularly if they are not a NET specialist or a recognised NET Centre.

Remember, I’m not a medical professional, so if you are in any doubt as to the status of your NET, you should discuss this directly with your specialist.  A good place to start is evidence of your Grade, Differentiation, Primary Site Location and Stage.

You may be interested in reading these associated posts:

Carcinoid vs Neuroendocrine

Neuroendocrine Neoplasms – Grading and Staging (WHO 2017)

Incurable vs Terminal

10 Questions for your doctor

Thanks for listening

Ronny

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Neuroendocrine Neoplasms – Grade and Stage (incorporating WHO 2017 changes)

Grades of Neuroendocrine Tumour

One of the most discussed and sometimes confusing subjects on forums is the staging and grading of Neuroendocrine Neoplasms (NENs). Mixing them up is a common error and so it’s important to understand the difference despite the apparent complexity. If I was to make a list of questions for my specialist/Oncologist at diagnosis, it would include “What is the stage, grade and differentiation of my cancer”.  To enable me to synchronise with the documented guidance, I’m going to use the following WHO 2017 approved terms in this post:

  • Neuroendocrine Neoplasm (NEN) – all types of Neuroendocrine tumour of whatever grade (please note Neoplasm is another word for tumour)
  • Neuroendocrine Tumour (NET) – all well-differentiated tumours (an explanation of differentiation will be provided below)
  • Neuroendocrine Carcinoma (NEC) – all poorly differentiated tumours

NEN Breakdown

Stage vs Grade

In the most basic of terms, stage is the spread or extent of cancer and grade is the aggressiveness of cancer. They are totally different things and an understanding of both is important as they are critical to predict outcome (to a certain extent) and guide therapy. There is no correlation between the two, you can have the lowest grade with the highest stage (actually very common with NETs).

As patients, we deal with many medical specialists during diagnosis and subsequent treatment.  However, we rarely meet the pathologist who plays a critical role in the outcome. Precise diagnosis is what drives patient decisions and treatment. If the pathology is wrong, everything that follows could be incorrect as well.  It’s a very important area.

Grading (aggressiveness)

Grading and Ki67

Antigen KI-67 is a nuclear protein that is associated with and may be necessary for cellular proliferation.  Ki-67 is therefore an excellent marker to determine the growth fraction of a given cell population. The fraction of Ki-67-positive tumour cells (the Ki-67 labeling index) is often correlated with the clinical course of cancer.

Pathologists normally need to count about a thousand cells in order to determine the percentage of cells that are Ki67 positive – thus why you see Ki67 expressed as a percentage. 0% is the lowest, 100% is the highest. Often, they add greater or less than signs depending on the sample involved, i.e. >5% or <5%. There are other measurement systems in place, mainly Mitotic Count.

The ranges for Neuroendocrine Neoplasms (NENs) are divided in to 3 Grades depending what range the Ki67 number lands in. With NENs, the differentiation (well or poorly) is almost as important at grade 3 (high grade).  Grades 1 and 2 are by default well differentiated NETs).

Why is differentiation important?

To fully understand grading, you also need to understand the concept of ‘differentiation’.  In the most basic of terms, ‘differentiation’ refers to the extent to which the cancerous cells resemble their non-cancerous counterparts.  This is an important point for NETs because many low-grade tumour cells can look very similar to normal cells. The differentiation of a NET has an impact on both prognostics and treatment regimes.

NENs fall into one of three grades based on their differentiation and their proliferative rate. The proliferative rate is measured mainly using two methods known as Miotic Count and Ki-67 index, the latter seems to be more frequently used (but see below for Lung NETs). The Ki-67 index can usually be determined, even in cases of small biopsies but Mitotic rate counting requires a moderate amount of tumour tissue (at least 50 HPFs or 10 mm) and may not be feasible for small biopsies.  The Miotic Count method may be preferred or used in addition to Ki-67 for certain Lung NET scenarios as it is said to be more helpful in distinguishing atypical from typical NET (what some might ‘old fashionably’ and incorrectly refer to as Lung Carcinoid tumours), and for small and large cell lung Neuroendocrine Carcinomas (NEC).

Some of you may have heard the term ‘moderately differentiated’ which tended to align with an intermediate grade or Grade 2. However, please note that the term moderately differentiated as a classification was phased out in 2010 by WHO reducing from 3 differentiation levels to 2.  Grade 2 is also defined as well differentiated but based on different proliferative rate (see table). High grade was normally referred to as Neuroendocrine Carcinoma indicating it is a faster growing and more aggressive cancer. However, see below for an important change to high grade classification.

Grading – Key WHO 2017 Changes

WHO Classifications of Cancer are published in something known in medical world as “The Blue Book”.  For NETs, the 2017 version comprises only the “WHO Classification of Tumours of Endocrine Organs”.  Technically this would preclude the digestive system and lung NETs but the leading NET pathologists have submitted a recommendation to normalise all NET Blue Books along the same classification scheme.  Worth also noting that the latest ENETS Guidelines are already using the new grading terms.  Many sites remain out of date so be careful where you look.

Misc Grading Issues

The proliferative rate can be diverse in NENs, so sampling issues can limit the accuracy of grading. More substantial samples of tumour are therefore preferable for grading thus why the Ki-67 index is preferred for biopsies where large amounts of tissue may not be available. The distinction of low-grade from intermediate grade can be challenging when using small samples. A couple of interesting observations about NET grading which I spotted during my research and ‘forum watching’.  You can have multiple primary tumours and these might have different Ki-67 scores.  Additionally, on larger tumours, Ki-67 scores can be different on different parts of the tumour.  And something I know from my own experience, secondary tumours can have different Ki-67 scores than primary – even a different grade.  In my own case, my liver secondary tumours were graded higher than my primary which according to my surgeon is in keeping with a clone of the disease having become more aggressive over time.  Royal Free Hospital NET Centre indicates a person’s grade should be taken from the highest biopsy grade taken. This is a fairly complex area but a recent study published by the US National Institute of Health and many anecdotal comments made by NET specialists indicates that is a fairly common scenario.

 

Summary of Key Changes

The 2017 World Health Organisation (WHO) classification sub-divided Grade 3 into two new entities: a well differentiated high-grade NET and a poorly differentiated high-grade NEC.  There may also be a cut-off point in proliferative rate (i.e. Ki-67) between NET and NEC in relation to potential treatment strategies (55% is mentioned for pNETs but I’m currently investigating). Physicians don’t really have much data to support specific guidelines for treatment so all cases will be personalised.

The Grade 1 to 2 Ki-67 cut-off is changed from 2 to < 3 for clarification purposes.  There was some discussion as to whether it should be <5 but this was not accepted.

Well differentiated High Grade NETs are now recognised.  These are known as a NET rather than a NEC.  Both Grade 3 (NET) and Grade 3 (NEC) have the same biopsy marker cut-offs as per the leading slide but it is thought that a threshold reading of 55% could have some influence on the treatment regime. For example, a well differentiated tumour with a Ki67 of less than 55% might benefit from the same treatment given to Grade 1 or 2 patients, whereas a well differentiated tumour with a Ki67 of more than 55% might benefit from the same treatment given to poorly differentiated NEC. Only a guideline and I suspect this is like many things in NENs, very individual, relies on many factors, so your specialist will drive this accordingly.  You may see these 2 grades listed as Grade 3a for NET and Grade 3b for NEC.

Previously, Pheochromocytoma did not have an official grading regime, i.e. they were just benign or malignant.  Now they are using the same grading system as above.  I’m assuming this is the same for Paraganglioma and I will confirm in due course.  This is an excellent change and a continuation from the WHO 2010 classification where there was great emphasis away from a benign/malignant classification to formal grade levels on the basis that all NETs have malignant potential.

It also introduced a change to the naming of mixed cell tumours from Mixed AdenoNeuroendocrine Carcinoma (MANEC) to Mixed Neuroendocrine Non-Neuroendocrine Neoplasms (MiNEN).  A full explanation of MiNEN will follow but I would suggest the use of the term ‘Neoplasm’ has been chosen rather than ‘Carcinoma’ is because these neoplasms can be well or poorly differentiated.

It’s not possible at this time to acquire copies of the official output but I will keep this blog live.

The source material for the 2017 version of this article.

From leading Pathologist Dr Anthony Gill – Remember this is based on Endocrine Organs only but it will eventually apply to all.   I am awaiting access to free documentation to update this article further – only ones I can currently find are not free!

 

Staging (spread)

Staging is the extent or spread of disease.  Most types of cancer have 4 stages, numbered from 1 to 4 indicating a rising spread as the number is bigger. Often doctors write the stage down in Roman numerals, perhaps this is to stop any confusion between standard numbers used for Grades? So you may see stages written as I, II, III and IV.  In addition to this standard method, there is also an agreed model known as TNM (Primary Tumour, Regional Node, Distant Metastasis) which is essentially a more detailed staging definition when combined with the Stage 1-4 model.  Please note with TNM models, there could be different stage descriptions depending on the location of the primary tumour and similarly different TNM models for different tumour locations.

WHO 2017 changes

WHO 2017 has recommended enhancements to the TNM system mainly the use of additional suffixes indicating the extent of lymph node involvement. Details to follow when I can free access.

The following example shows the stage descriptions for a NET of the small intestine (the others are similar but worded accordingly for that part of the anatomy):

Stage I tumour is less than 1 cm in size and has not spread to the lymph nodes or other parts of the body.

Stage II tumour is greater than 1 cm in size and has started to spread beyond the original location, but has not spread to the lymph nodes or other parts of the body.

Stage III is any size tumour that has spread to nearby areas of the body and also to at least one lymph node.

Stage IV is any size tumour that has spread to one or more lymph nodes and has also spread to other, more distant areas of the body (such as the liver).

It’s also worth pointing out that Stage IV does not necessarily mean a cancer is more dangerous than other cancers of lesser stages.  This is an important point for NETs where Stage 4 can be matched up with a low-grade tumour i.e. Stage 4 for lower grade NETs is very often not the ‘red flag’ it is for other more aggressive cancers.  For example, doctors may surgically remove a Stage IV NET, while surgery might not help a patient with a cancer of a higher grade at such a late stage.

Notes:

  • Sometimes doctors use the letters to further divide the number categories – for example, stage 2A or stage 3B.  This is normally to clarify or provide more detail of the primary tumour size/invasion in conjunction with the TNM model.
  • You may also see something called Stage 0 which is for ‘Carcinoma in situ’. It means that there is a group of abnormal cells in an area of the body. However, the number of abnormal cells is too small to form a tumour and may, therefore, be currently classed as benign.  The World Health Organisation (WHO) system does not appear to recognise Stage 0 for NETs.

The most generic model for TNM staging is below but please note this could be adjusted for particular types of NET.

Primary Tumor (T)
TX: Primary tumor cannot be evaluated
T0: No evidence of primary tumour
Tis: in situ (abnormal cells are present but have not spread to neighbouring tissue; although not cancer, in situ may become cancer and is sometimes called preinvasive cancer)

T1, T2, T3 and T4 is a measure of the size of, and/or invasion/penetration by, the primary tumour and the wording varies between different NET sites. e.g. for a small intestinal NET:

T1 tumour invades mucosa or submucosa and size <=1 cm

T2 tumour invades muscularis propria or size >1 cm

T3 tumour invades subserosa

T4 tumour invades the visceral peritoneum (serosa)/other organs

For any T add (m) for multiple tumours

Regional Lymph Nodes (N)
NX: Regional lymph nodes cannot be evaluated
N0: No regional lymph node involvement
N1: regional lymph node metastasis

Distant Metastasis (M)
MX: Distant metastasis cannot be evaluated
M0: No distant metastasis
M1: Distant metastasis is present

You may occasionally see TNM staging be prefixed by lower case letters.  The most commonly used prefix is ‘p’ simply meaning the grading has been confirmed by pathology.  e.g. pT4 N1 M1

Specialists can combine the Stage to create a TNM – for example:

This slide will be updated when I get access to WHO 2017 or updated AJCC pubication.

Summary

A complex area and I hope I have condensed it sufficiently for you to understand enough for your purposes.  Despite looking very scientific, it is not an exact science. There are many variables as there always are with Neuroendocrine disease.  NENs can be very challenging for a pathologist even an experienced one who may not have encountered NENs before.  However, it is an extremely important part of initial diagnosis and also when needed during surveillance.  It is a vital tool used by Multidisciplinary Teams (MDT) in treatment plans and for prognostic purposes.  If you need to learn further, I recommend this document:

If you are interested in this subject and have one hour to spare, there is a great video here from LACNETS worth watching.

Finally – always make sure you get your pathology results at diagnosis and following any subsequent sampling.

You may benefit from reading these associated posts:

Benign vs Malignant

Incurable vs Terminal

Carcinoid vs Neuroendocrine

10 Questions for your doctor

Looking for a needle in a haystack

Thanks for reading

Ronny

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Carcinoid vs Neuroendocrine

OPINION

CARCINOID misnomer etc

There’s a constant debate regarding the validity of the term ‘Carcinoid‘.  I’ve posted about this a few times and as far as I know, the debate has been raging for some years.

You may have noticed that ‘Carcinoid’ is often used as a standalone word and tends not to be suffixed with the word ‘Cancer’ or ‘Tumour’ – unlike Bowel Cancer, Breast Cancer, Prostrate Cancer, Lung Cancer, Brain Tumour, etc.  Nobody goes around saying “Breast” or “Bowel” do they?  But they happily say “Carcinoid”.  Unfortunately, the term ‘Carcinoid’ has become entrenched in both pathology and clinical literature over the past 100 years. The main problem with the word Carcinoid is that it means different things to different people. Some use the term almost exclusively to designate serotonin-producing tumours that arise from the enterochromaffin cells that can result in carcinoid syndrome i.e. most commonly in the appendix, small intestine, stomach, lung, rectum and uncommonly in other places. Some use it to (incorrectly) refer to all Neuroendocrine Tumours. The most worrying connotation of the use of the word ‘Carcinoid’ is the belief that they all have benign clinical and biological behaviour.  That is dangerous thinking and has the potential to kill people.  Fortunately, NET specialists are starting to move away from using the word – check out the quote below:
carcinoid falling out of favor

Siegfried Oberndorfer
Siegfried Oberndorfer

The Origins

The following history of ‘Carcinoid’ is well documented: Siegfried Oberndorfer (1876-1944) became the first to adequately characterise the nature of Carcinoid tumours and refer to them as “benign carcinomas.” During his tenure at the Pathological Institute of the University of Munich, Oberndorfer noted in 1907 that the lesions were distinct clinical entities and named them “karzinoide” (“carcinoma-like“), emphasizing in particular their benign features. However, In 1929 he amended his classification to include the possibility that these small tumours could be malignant and also metastasise. (Author’s note – a name change would have been handy at this point).

100 years later

NANETS, UKINETS and ENETS seem to defer to the WHO classification nomenclature and it is here another term is introduced – Neuroendocrine Neoplasms (NENs).  NANETs state that “all of the entities under discussion are neoplastic, and neoplasm is therefore a more accurate term than tumor, which means only a mass“.  These organisations tend to use the term Neoplasm as a catch-all for all Neuroendocrine disease and then the term ‘tumor’ and ‘carcinoma’ applies to well and poorly differentiated respectively.  It’s worth noting that since 2010, the WHO classification is based on the concept that all NETs have malignant potential, and has therefore abandoned the division into benign and malignant NETs and tumours of uncertain malignant potential. Neuroendocrine Carcinoma is malignant by defintion. All of this has been reinforced in the 2017 publication. The term ‘Carcinoid’ is conspicuously missing from these texts.

To put it simply – the term ‘carcinoid’ is no longer credible

Due to its historical meaning, Carcinoid does not adequately convey the potential for malignant behaviour that accompanies many of these neoplasms as described above.  The term Carcinoid decodes to ‘Carcinoma like’.  Contextually “Carcinoid Cancer” decodes to “carcinoma like cancer” which is, of course, totally misleading and its use simply perpetuates the claim by some that it is ‘not a proper cancer’.  If we only needed one reason to ditch the word ‘Carcinoid’, this would be it.

carcinoid is inadequate oberg quote 2016

I mentioned confusion above and this has led to a hybrid effect of naming the condition.  For example, there is a tendency by some (including medical establishments and patient organisations) to use the term ‘Carcinoid’ and ‘Neuroendocrine Tumors’ interchangeably which is patently incorrect. Neither is it helpful that many patients and organisations continue to refer to this disease as “Carcinoid Neuroendocrine Tumor”, “Neuroendocrine Carcinoid Tumor”, “Neuroendocrine Carcinoid Cancer”, “Carcinoid/Neuroendocrine”, “CNET”; and many other variations along these lines. Many seemingly credible organisations will say “Carcinoid and Neuroendocrine Tumors” not realising it’s a contradiction in terms. Continued use of the term in any phrase or standalone context is not doing our case for recognition any good – it’s bad enough that some seem to cling to outdated and invalid diagnostic clichés and icons from the 1980s.  All of it needs to go.

carcinoid npf quote

I know I’m not alone in this thinking given the decrease of its use in the NET world, including NET Specialists (see lead graphic) and NET Specialist organisations (some have changed their names).  There’s an interesting article written by a NET specialist where the term ‘carcinoid’ is described as “unfortunate”, “misleading”, “outmoded”, “archaic”, “confusing” and “misnomer”. Exactly!  In the recent SEER NET study, a NET specialist reaffirmed this thinking by stating that “the belief these tumors did not metastasize, did not reach any great size, and appeared harmless, has since been proven false”.  Continued use of the term ‘Carcinoid’ has the potential to regress this thinking.  We must not let this happen.

referring to carcinoid

So what terms should we be using?

People and organisations will be out of date with modern Neuroendocrine Neoplasms nomenclature and some will still want to continue with their own nomenclature (….. and because of the confusion, some will fall into both categories not realising they’re out of date).  Here’s a classic example of the problem we face – the American Cancer Society(ACS) does not even list Neuroendocrine Tumor as a cancer type.  Instead you can find “Gastrointestinal Carcinoid Tumors” and “Lung Carcinoid Tumor”. You’ll find Pancreatic NETs inside Pancreatic Cancer.  Americans should harangue the ACS to get this right. I could go on with many similar observations on seemingly respectable sites. I intentionally used a US example as this country appears to be way behind in the changes to NET nomenclature, pretty surprising as they tend to be at the forefront of many other aspects in the world of NETs.

Personally, I think the acceptance of a common worldwide nomenclature should come from the World Health Organisation (WHO) classification for Neuroendocrine Neoplasms.  They are divided into a number of chapters including ‘Endocrine Organs’, Digestive System, Lung Tumours….. and no doubt some others.  Frustrating, but medical people tend to look at things in anatomical terms. Nonetheless, the agreed classification nomenclature for the whole group of Neuroendocrine Neoplasms can be found with some research and access to clinical publications.  The correct nomenclature should then be flowed down in regional groupings, e.g. ENETS representing Europe, NANETS representing North America, etc.  As I understand it, ENETS and UKINETS are already essentially aligned with WHO and NANETS appears to be. From these organisations, the use of the correct terminology should then rub off on patients, patient advocate organisations and general cancer sites.  However, the biggest challenge will be with hospitals/medical centres, cancer registries and insurance companies whose medical record processing is run using reference data (think drop down selections and database structures).  Easier said than done but ‘change’ always has to start somewhere.  Technically it has started (albeit late) as the big NET medical organisations are already starting to reduce the use of outmoded words such as ‘carcinoid’.

I once argued that the term ‘carcinoid’ needed to be retained as it represented a histopathological grouping of a particular type of NET comprising mostly appendiceal, stomach (gastric), rectal, small intestine and lung NETs.  However, reading through the ENETS 2016 guidance in conjunction with the most up to date WHO classification publications, I’ve changed my mind after noticing they no longer use the word ‘Carcinoid’ in relation to a tumor type.  Rather, they use the latest WHO terms above and then use the anatomy to distinguish the different types of NET (like we already do for Pancreatic NET or pNET).

Perhaps patients can lead the way here ………

Rather than say:

‘Carcinoid’ or ‘Carcinoid Tumor’….. why not say Neuroendocrine Tumor or NET (adding your primary location if required – see below);

‘Carcinoid Cancer; ….. why not say Neuroendocrine Cancer;

‘Lung Carcinoid’ ….. why not say Lung NET (adding typical or atypical if required);

‘Small intestine Carcinoid’, why not say Small Intestine NET (or ‘SiNET which is becoming popular); p.s. I’m not a fan of ‘small bowel’ due to the potential for confusion with the widely used term ‘bowel cancer’);

‘Gastric Carcinoid’, why not say Gastric NET (adding your type if required);

‘Rectal Carcinoid’, why not say Rectal NET;

‘Appendiceal Carcinoid’, why not say Appendiceal NET;

…. and so on.  And you can add your stage and grade/differentiation for a richer picture.

You can listen to a very well known NET Specialist say something similar in this video here.

Worth noting that even ENETS and NANETS cannot agree on tumor type terminology – the latter uses Small Bowel NETs (SBNETs) whereas ENETS uses Small Intestine NENs (SiNENs). I did say it’s easier said than done.

As I said above, the term ‘Carcinoid’ has become entrenched in both pathology and clinical literature over the past 100 years so it will still appear in many texts and need to be searchable online to support medical and advocacy business.  However, these are technical issues and I don’t therefore believe people need to use the terms to make them searchable online.  I tag all my posts with ‘Carcinoid’ even if I don’t mention the word in my text.  I have started only using the term for context when it is required and am currently reviewing all of my posts to ensure that is still the case.

Hang on…what about Carcinoid Syndrome

When someone wants to know which syndrome you have, you can’t just state (say) “small intestine syndrome” or “midgut syndrome”.  ‘NET Syndrome’ doesn’t work either as there are several NET syndromes.  This has led to the situation where people try to drop the word ‘carcinoid’ and just say “the syndrome” which is even more confusing! I accept this one is a difficult challenge but I don’t believe it’s insurmountable, just needs some willpower and agreement.  I could come up with other terms in about 5 minutes.

What about Carcinoid Heart Disease

Personally I don’t see why this cannot be renamed to ‘Neuroendocrine Heart Disease’ or its technical name – ‘Hedinger syndrome’.

What about Carcinoid Crisis

World renowned NET specialists already make statements that these issues can apply to all types of NET; and it’s well-known that a similar crisis situation already applies to other types e.g. Pheochromocytomas.  I cannot see why something along the lines of ‘Neuroendocrine Crisis’ or ‘NET Crisis’ would not be acceptable.

Summary

We as patients are unlikely to be able to force changes on the medical and insurance communities but we can be a ‘force for change’ by setting the example of using a correct and more apt terminology to describe our disease.

 

Thanks for listening

Ronny

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