Neuroendocrine Tumours: a spotlight on Pheochromocytomas and Paragangliomas

spotlight on pheo para

I spend a lot of time talking about the most common forms of Neuroendocrine Tumours (NETs), but what about the less well-known types?  As part of my commitment to all types of NETs, I’d like to shine a light on two less common tumour types known as Pheochromocytomas and Paragangliomas – incidence rate approximately 8 per million per year. They are normally grouped together and the definitions below will confirm why.  If you think it’s difficult to diagnose a mainstream NET, this particular sub-type is a real challenge.

So, let’s get definitions out of the way:

Pheochromocytomas (Pheo for short)

Pheochromocytomas are tumours of the adrenal gland that produce excess adrenaline. They arise from the central portion of the adrenal gland, which is called the adrenal medulla (the remainder of the gland is known as the cortex which performs a different role and can be associated with a different tumour type). The adrenal medulla is responsible for the normal production of adrenaline, which our body requires to help maintain blood pressure and to help cope with stressful situations.  The adrenal glands are situated on top of the kidneys (i.e. there are two). Adrenaline is also called ‘epinephrine’ which is curiously one of the 5 E’s of Carcinoid Syndrome.

Paragangliomas (Para for short)

Paragangliomas are tumours that grow in cells of the ‘peripheral’ nervous system (i.e. the nerves outside the brain and spinal cord). Like Pheochromocytomas, they can release excess adrenaline.  There can be confusion between the two types of tumour as Paragangliomas are often described as extra-adrenal Pheochromocytomas (i.e. a Pheo external to the adrenal gland).

Going forward, I’m going to talk about both using the single term of ‘Pheochromocytoma’ in the context of an adrenaline secreting tumour but may refer to Paraganglioma where there might be a difference other than anatomical location.

Pheochromocytomas are often referred to as the “ten percent tumour” because as a rule of thumb they do many things about ten percent of the time. However, these figures are slowly changing, so this label is gradually becoming less apparent. The following is a fairly exhaustive list of these characteristics:

A few facts about Pheochromocytomas

  • As much as 1 in 3 are Malignant but most have undetermined biologic potential.  A recent document issued by the World Health Organisation (WHO) stated that “Paragangliomas should not be termed benign”.
  • Around 10% of Pheochromocytomas are Bilateral (i.e. found in both adrenal glands: 90% arise in just one of the two adrenal glands)
  • Around 10% are Extra-Adrenal (found within nervous tissue outside of the adrenal glands … i.e. 10% are Paragangliomas)
  • Around 10% are found in Children (i.e. 90% in adults)
  • Up to 30% are Familial potentially rising to 50% for metastatic cases and Multiple Endocrine Neoplasia (MEN) involvement.
  • The recurrence rate is around 16%, i.e. about 1 in 6 patients have a tumor that comes back after surgery.  Tumors that come back also have the potential to be malignant. If you have pheo or para and have surgery to remove it, be sure to continue to check in with your doctor to monitor for any returning tumors.
  • Present with a stroke (10% of these tumours are found after the patient has a stroke)

Symptoms

The classic symptoms of Pheochromocytomas are those attributable to excess adrenaline production. Often these patients will have recurring episodes of sweating, headache, and a feeling of high anxiety.

  • Headaches (severe)(one of the classic triad, see below)
  • Excess sweating (generalized)(one of the classic triad, see below)
  • Racing heart (tachycardia and palpitations)(one of the classic triad, see below)
  • Anxiety and nervousness
  • Hypertension
  • Nervous shaking (tremors)
  • Pain in the lower chest or upper abdomen
  • Nausea (with or without vomiting)
  • Weight loss
  • Heat intolerance

Diagnosing Pheochromocytomas

According to the ISI Book on NETs (Woltering, Vinik, O’Dorisio, et al), Pheochromocytomas present with a classic triad of symptoms and signs:  headache, palpitations and sweating.  This symptom complex has a high specificity and sensitivity (>90%) for the diagnosis of Pheochromocytomas.  The figure is much lower in individual symptom presentations (palpitations 50%, sweating 30%, headaches 20%). In addition to correctly diagnosing from these symptoms, Pheochromocytomas may also be found incidentally during a surgical procedure even after a diagnosis of an ‘adrenal incidentaloma’

Markers.  Like serotonin secreting tumours, adrenal secreting tumours convert the offending hormone into something which comes out in urine. In fact, this is measured by 24 hour urine test very similar to 5HIAA (with its own diet and drug restrictions).  It’s known as 24-hour urinary catacholamines and metanephrines. This test is designed to measure production of the different types of adrenaline compounds that the adrenal glands make. Since the body gets rid of these hormones in the urine, we simply collect a patient’s urine for 24 hours to determine if they are over-produced.  Like 5HIAA, there is also a plasma (blood draw) version of the test.  According to the ISI Book on NETs, there is also an additional test called ‘Vanillylmandelic Acid (VMA).  This reference also indicates the most sensitive test is plasma free total metanephrines. Also read more here.

Genetics.  The familial connection with Pheo/Para is complex. Up to 13 genes have been identified including NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2(SDH5), TMEM127, MAXm EPAS1, FH, MDH2.  Read more here ( recent update)The NIH also have a useful section –click here.

Scans.  Other than the usual range of scanners, ultrasound, CT/MRI, all of which may be used to find evidence of something, the other scan of note is called MIBG.  This is a nuclear scan similar in concept to the Octreotide Scan given to many NET patients (in fact some Pheo patients my get an Octreotide scan if they have somatostatin receptors).  The key differences with MIBG is the liquid radioactive material mix which is called iodine-123-meta-iodobenzylguanidine or 131-meta-iodobenzylguanidine  (this is where the acronym MIBG originates).  Together with the markers above, the results will drive treatment.  Depending on availability, the latest PET scans may also be available potentially offering greater detail and accuracy i.e. 18F-FDOPA, 18F-FDG and Ga68.  Read more on scans here.

This statement and diagram was provided by Dr Mark Lewis who is an Oncologist and MEN patient.  “The algorithm for working up a hyperadrenergic state is attached (and was developed by Dr. Young at Mayo Clinic). It outlines the most reliable testing for a pheo or Paraganglioma”

work-up-for-diagnosing-pheo

Additional Factors and Considerations

  1. This is an awareness post so I’m not covering treatment options in any detail except to say that surgery if often used to remove as much tumour as possible.   Somatostatin Analogues may also be used in certain scenarios in addition to other hormone suppression or symptom controlling drugs. That said, Pheo/Para patients may be interested in a PRRT trial exclusively for Pheo/Para – read more here (see section entitled – “What about Pheo/Para”)
  2. The adrenal cortex mentioned above is actually the site for Adrenocortical Carcinoma (ACC) – this is a totally different cancer.
  3. Pheochromocytomas are probably difficult to diagnose (you only have to look at the symptoms to see that).  The differential diagnoses (i.e. potential misdiagnoses) are: hyperthyroidism, hypoglycaemia, mastocytosis, carcinoid syndrome, menopause, heart failure, arrhythmias, migraine, epilepsy, porphyria lead poisoning, panic attacks and fictitious disorders such as the use of cocaine and benzedrine.
  4. Many Pheochromocytoma patients will also be affected by Multiple Endocrine Neoplasia (MEN), in particular MEN2 (there are some wide-ranging percentage figures online for this aspect).  There can also be an association with Von Hippel-Lindau (VHL) syndrome and less commonly with Neurofibromatosis type 1.
  5. Given the nature of the hormones involved with Pheochromocytomas, there is a risk of intraoperative hypertensive crises. This is similar in some ways to Carcinoid Crisis but needs careful consideration by those involved in any invasive procedure.

Newly Approved Drug – AZEDRA

On 30th July 2018, Progenics Pharmaceuticals Announces FDA Approval for AZEDRA® (iobenguane I 131) to Treat Unresectable, Locally Advanced or Metastatic Pheochromocytoma or Paraganglioma – read more by clicking here.

Summary

Pheochromocytomas are very complex involving many of the challenges found in the more abundant and common types of NETs.  To underscore this statement, please see this case study where one patient was misdiagnosed with psychiatric problems for 13 years before being correctly diagnosed with a metastatic Pheochromocytoma.

Also  ….. take a look at this awareness video produced by the Pheo Para Alliance. I voted this as the best piece of NET awareness in 2017. click here to watch

This is an extremely basic overview offered as an awareness message about the lesser known types of NETs.  I refer you to my disclaimer.  If you wish to learn more about Pheochromocytomas and Paragangliomas, check out the links below.

Research References used in this post:

Know Pheo/Para from Progenics Pharma

ISI – Neuroendocrine Tumors 2016

http://pheopara.org/ (in August 2017, the Pheo Para Troopers and the Pheo Para Project Merged)

http://www.pheosupportfoundation.org/

http://www.pheochromocytoma.org/

http://endocrinediseases.org/

https://www.endocrineweb.com/

Various authoritative Neuroendocrine and Endocrine Sites.

Also ……why not take a look at these Pheo boggers:

  1. Kirsty Dalglishhttps://kirstywestwood.wordpress.com/
  2. to follow

 

Thanks for reading

Ronny

I’m also active on Facebook. Like my page for even more news. I’m also building up this site here: Ronny Allan

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

Ronny Allan is an award winning patient leader and advocate for Neuroendocrine Cancer.

 

Neuroendocrine Cancer – don’t let it be a Crisis

crisis

The word ‘crisis’ has a wide range of meanings and it’s well used in the media to catch the reader’s attention. Lately, the terms ‘political crisis’, financial ‘crisis’ and ‘constitutional crisis’ appear almost daily in media headlines. In a previous life, the term ‘crisis management’ was used daily in the work I was undertaking as I went from problem to problem, dampening or putting out fires (….. that’s a metaphor!).  Thinking back, my adrenaline (epinephrine), norepinephrine, and cortisol must have been very busy! 

However, in the world of Neuroendocrine Tumours (NETs), ‘crisis’ has a very significant meaning and its very mention will make ears prick up.  The word ‘crisis’ is normally spoken or written using the term ‘Carcinoid Crisis’ given this is the type of NET with which it has been mostly associated. However, I’ve studied and researched and it would appear that some form of ‘crisis’ might apply to other types of NETs. Perhaps this is another knock-on effect caused by the historical use of the word ‘Carcinoid’ to incorrectly refer to all NETs. In terms of ‘crisis’, maybe there should be a more generic NETs wide term?  Of course there should, once again ‘carcinoid’ is causing confusion.

What is (so called) ‘Carcinoid Crisis’?

In the simplest of terms, it is a dangerous change in blood pressure, heart rate, and breathing (technical term – cardiopulmonary hemodynamic instability).  On an operating table under anaesthetics or an invasive procedure such as liver embolization, this can actually be life threatening.  Incidentally, this happens with many other types of conditions (hormones and peptides do exist in other illnesses). However, with a patient already oversecreting these hormones and peptides, it could be a life or death situation.

What is the difference between carcinoid crisis and carcinoid syndrome?

Carcinoid crisis is said to be a situation where nearly all of the possible symptoms of carcinoid syndrome come at the same time and in some severity. Carcinoid crisis is a serious and life-threatening complication of carcinoid syndrome, and is generally found in people who already have carcinoid syndrome. The crisis may occur suddenly, or it can be associated with stress, a reaction to treatment, but it is mainly as a result of the use of anaesthesia. There is a thin line between a very severe bout of carcinoid syndrome and carcinoid crisis but generally it can be characterized by an abrupt flushing of face and sometimes upper body, usually severe falls in blood pressure and even bronchospasm with wheezing can infrequently occur. The attack may look like a severe allergic reaction.

It is said by one very well-known NET expert to “not to be something which happens randomly to all patients, it is usually linked to a medical procedure of some sort when you are having anaesthesia”.  Dr Eric Liu also said “Luckily it is relatively uncommon”.

Why does it happen to some NET Patients?

NETs can release a variety of ‘vasoactive peptides’ (hormones) in excess (e.g. serotonin, catecholamines, histamine).  Under normal circumstances, these would just present as routine syndromes which may need to be controlled in most cases with somatostatin analogue treatment (Octreotide/Lanreotide).

Excess amounts of these vasoactive substances can cause both hypertension and hypotension (high and low blood pressure respectively). In extreme cases this can lead to what is known as a crisis situation.

How is the risk managed?

Most people are effectively managed on monthly injections of Octreotide/Lanreotide but some people still need ‘rescue shots’ (top ups) where they are experiencing breakthrough symptoms.  When I was symptomatic (syndromic), I would regularly flush in stressful situations but that was definitely syndrome rather than crisis. Check out my video explaining how I felt.  It’s worth reading something called the 5 E’s of Carcinoid Syndrome, probably useful to other types of NETs as I’m sure there is some overlap.

If you research this plus perhaps from your own experience, you will know there are different ideas and ‘protocols’.  However, they all mostly involve some pre-procedure infusion of a somatostatin analogue (normally Octreotide) – although I’d love to hear from anyone who has had Lanreotide as an alternative.  Some doctors or hospitals are known to have their own ‘protocols’ and I’ve uploaded the one from the ISI NET book page 215 (Wang, Boudreaux, O’Dorisio, Vinik, Woltering, et al). Click here.  Please note this is an example rather than a recommendation as this is something the NOLA team have developed for their own centre.

In all the big procedures I’ve had done in my local NET Centre, I have always been admitted the day before to receive what they describe as an ‘Octreotide Soak’.  The link below is an example of the UK standard for pre and peri-operative protection (please note your NET team may be working to a slightly different protocol based on their own version of best practice, just to emphasise that this is an example and not advice).

Useful guidance from UKINETS – click here

Patients are always asking about the risk and requirements for smaller procedures such as an Endoscopy.  There does not seem to common guidance on this but Dr Woltering who is always forthcoming with advice suggests 200 micrograms of Octreotide before the procedure commences.

Dental visits involving anaesthetics can also be an issue and you can see Dr Woltering’s advice in my blog about the 5 Es of Carcinoid Syndrome.  Additionally there is advice for users of ‘Epi Pens’. You also need to derisk those situations.

What about other types of NETs

The ISI Book Link above (here for convenience), does stateregardless of tumor type, all NETs should be pre-treated with Octreotide for protection against crisis.  I know that NET patients other than those with ‘Carcinoid Tumours’ are also treated with somatostatin analogues, as they too can be subject to the effects of excess secretion of certain vasoactive peptides.

Why is the issue relative to Pheochromocytoma/Paraganglioma? 

Pheochromocytomas and paragangliomas are catecholamine-producing neoplasms that can cause life-threatening hemodynamic instability, particularly intraoperatively, when the tumor is manipulated.  In some ways their version of ‘crisis’ is more complex and dangerous than in the issues with carcinoid crisis above.  There needs to be significant pre-operative preparation in addition to peri-operative measures, in fact with this type of tumour, post surgical treatment and monitoring is also required.

I recently read an article about a person with a Pheochromocytoma. The person had what was described as an ‘Intraoperative Hypertensive Crisis‘ that appeared to be caused by her tumour type rather than the sort of incident that might occur in a standard surgery.  Hypertension (high blood pressure) can be a symptom of Pheochromocytoma so you can see the problem with surgery and other procedures. An interesting issue with this type of NET is that after surgery, the patient is at risk for hypotension (low blood pressure) from venous dilation caused by the sudden withdrawal of catecholamines. Read more here.

Summary

I highly suspect there are many examples from the NET world beyond the ‘carcinoid’ subtype of NETs and I’ve already given you one above.  I’ll update this blog as I discover other examples.  In the meantime, make sure you ask your medical team about ‘crisis protection’ if you are to undergo any surgical or invasive medical procedure. Minor procedures should also be assessed. 

Do we need to rename the term Carcinoid Crisis to Neuroendocrine Crisis?  Probably …… let’s give it a red card!

Thanks for reading

Ronny

I’m also active on Facebook.  Like my page for even more news.  I’m also building up this site here: Ronny Allan

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

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